Merge branch 'akpm' (patches from Andrew)

Merge still more updates from Andrew Morton:
 "16 patches.

  Subsystems affected by this patch series: ofs2, nilfs2, mailmap, and
  mm (madvise, mlock, mfence, memory-failure, kasan, debug, kmemleak,
  and damon)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/damon: prevent activated scheme from sleeping by deactivated schemes
  mm/kmemleak: reset tag when compare object pointer
  doc/vm/page_owner.rst: remove content related to -c option
  tools/vm/page_owner_sort.c: remove -c option
  mm, kasan: fix __GFP_BITS_SHIFT definition breaking LOCKDEP
  mm,hwpoison: unmap poisoned page before invalidation
  mailmap: update Kirill's email
  mm: kfence: fix objcgs vector allocation
  mm/munlock: protect the per-CPU pagevec by a local_lock_t
  mm/munlock: update Documentation/vm/unevictable-lru.rst
  mm/munlock: add lru_add_drain() to fix memcg_stat_test
  nilfs2: get rid of nilfs_mapping_init()
  nilfs2: fix lockdep warnings during disk space reclamation
  nilfs2: fix lockdep warnings in page operations for btree nodes
  ocfs2: fix crash when mount with quota enabled
  Revert "mm: madvise: skip unmapped vma holes passed to process_madvise"

.mailmap

@@ -213,6 +213,7 @@ Kees Cook <keescook@chromium.org> <kees@ubuntu.com>
 Keith Busch <kbusch@kernel.org> <keith.busch@intel.com>
 Keith Busch <kbusch@kernel.org> <keith.busch@linux.intel.com>
 Kenneth W Chen <kenneth.w.chen@intel.com>
+Kirill Tkhai <kirill.tkhai@openvz.org> <ktkhai@virtuozzo.com>
 Konstantin Khlebnikov <koct9i@gmail.com> <khlebnikov@yandex-team.ru>
 Konstantin Khlebnikov <koct9i@gmail.com> <k.khlebnikov@samsung.com>
 Koushik <raghavendra.koushik@neterion.com>

Documentation/vm/page_owner.rst

@@ -125,7 +125,6 @@ Usage
    additional function:
 
 	Cull:
-		-c		Cull by comparing stacktrace instead of total block.
 		--cull <rules>
 				Specify culling rules.Culling syntax is key[,key[,...]].Choose a
 				multi-letter key from the **STANDARD FORMAT SPECIFIERS** section.

Documentation/vm/unevictable-lru.rst

@@ -52,8 +52,13 @@ The infrastructure may also be able to handle other conditions that make pages
 unevictable, either by definition or by circumstance, in the future.
 
 
-The Unevictable Page List
--------------------------
+The Unevictable LRU Page List
+-----------------------------
+
+The Unevictable LRU page list is a lie.  It was never an LRU-ordered list, but a
+companion to the LRU-ordered anonymous and file, active and inactive page lists;
+and now it is not even a page list.  But following familiar convention, here in
+this document and in the source, we often imagine it as a fifth LRU page list.
 
 The Unevictable LRU infrastructure consists of an additional, per-node, LRU list
 called the "unevictable" list and an associated page flag, PG_unevictable, to
@@ -63,8 +68,8 @@ The PG_unevictable flag is analogous to, and mutually exclusive with, the
 PG_active flag in that it indicates on which LRU list a page resides when
 PG_lru is set.
 
-The Unevictable LRU infrastructure maintains unevictable pages on an additional
-LRU list for a few reasons:
+The Unevictable LRU infrastructure maintains unevictable pages as if they were
+on an additional LRU list for a few reasons:
 
  (1) We get to "treat unevictable pages just like we treat other pages in the
      system - which means we get to use the same code to manipulate them, the
@@ -72,13 +77,11 @@ LRU list for a few reasons:
      of the statistics, etc..." [Rik van Riel]
 
  (2) We want to be able to migrate unevictable pages between nodes for memory
-     defragmentation, workload management and memory hotplug.  The linux kernel
+     defragmentation, workload management and memory hotplug.  The Linux kernel
      can only migrate pages that it can successfully isolate from the LRU
-     lists.  If we were to maintain pages elsewhere than on an LRU-like list,
-     where they can be found by isolate_lru_page(), we would prevent their
-     migration, unless we reworked migration code to find the unevictable pages
-     itself.
-
+     lists (or "Movable" pages: outside of consideration here).  If we were to
+     maintain pages elsewhere than on an LRU-like list, where they can be
+     detected by isolate_lru_page(), we would prevent their migration.
 
 The unevictable list does not differentiate between file-backed and anonymous,
 swap-backed pages.  This differentiation is only important while the pages are,
@@ -92,8 +95,8 @@ Memory Control Group Interaction
 --------------------------------
 
 The unevictable LRU facility interacts with the memory control group [aka
-memory controller; see Documentation/admin-guide/cgroup-v1/memory.rst] by extending the
-lru_list enum.
+memory controller; see Documentation/admin-guide/cgroup-v1/memory.rst] by
+extending the lru_list enum.
 
 The memory controller data structure automatically gets a per-node unevictable
 list as a result of the "arrayification" of the per-node LRU lists (one per
@@ -143,7 +146,6 @@ These are currently used in three places in the kernel:
      and this mark remains for the life of the inode.
 
  (2) By SYSV SHM to mark SHM_LOCK'd address spaces until SHM_UNLOCK is called.
-
      Note that SHM_LOCK is not required to page in the locked pages if they're
      swapped out; the application must touch the pages manually if it wants to
      ensure they're in memory.
@@ -156,19 +158,19 @@ These are currently used in three places in the kernel:
 Detecting Unevictable Pages
 ---------------------------
 
-The function page_evictable() in vmscan.c determines whether a page is
+The function page_evictable() in mm/internal.h determines whether a page is
 evictable or not using the query function outlined above [see section
 :ref:`Marking address spaces unevictable <mark_addr_space_unevict>`]
 to check the AS_UNEVICTABLE flag.
 
 For address spaces that are so marked after being populated (as SHM regions
-might be), the lock action (eg: SHM_LOCK) can be lazy, and need not populate
+might be), the lock action (e.g. SHM_LOCK) can be lazy, and need not populate
 the page tables for the region as does, for example, mlock(), nor need it make
 any special effort to push any pages in the SHM_LOCK'd area to the unevictable
 list.  Instead, vmscan will do this if and when it encounters the pages during
 a reclamation scan.
 
-On an unlock action (such as SHM_UNLOCK), the unlocker (eg: shmctl()) must scan
+On an unlock action (such as SHM_UNLOCK), the unlocker (e.g. shmctl()) must scan
 the pages in the region and "rescue" them from the unevictable list if no other
 condition is keeping them unevictable.  If an unevictable region is destroyed,
 the pages are also "rescued" from the unevictable list in the process of
@@ -176,7 +178,7 @@ freeing them.
 
 page_evictable() also checks for mlocked pages by testing an additional page
 flag, PG_mlocked (as wrapped by PageMlocked()), which is set when a page is
-faulted into a VM_LOCKED vma, or found in a vma being VM_LOCKED.
+faulted into a VM_LOCKED VMA, or found in a VMA being VM_LOCKED.
 
 
 Vmscan's Handling of Unevictable Pages
@@ -186,28 +188,23 @@ If unevictable pages are culled in the fault path, or moved to the unevictable
 list at mlock() or mmap() time, vmscan will not encounter the pages until they
 have become evictable again (via munlock() for example) and have been "rescued"
 from the unevictable list.  However, there may be situations where we decide,
-for the sake of expediency, to leave a unevictable page on one of the regular
+for the sake of expediency, to leave an unevictable page on one of the regular
 active/inactive LRU lists for vmscan to deal with.  vmscan checks for such
 pages in all of the shrink_{active|inactive|page}_list() functions and will
 "cull" such pages that it encounters: that is, it diverts those pages to the
-unevictable list for the node being scanned.
+unevictable list for the memory cgroup and node being scanned.
 
 There may be situations where a page is mapped into a VM_LOCKED VMA, but the
 page is not marked as PG_mlocked.  Such pages will make it all the way to
-shrink_page_list() where they will be detected when vmscan walks the reverse
-map in try_to_unmap().  If try_to_unmap() returns SWAP_MLOCK,
-shrink_page_list() will cull the page at that point.
+shrink_active_list() or shrink_page_list() where they will be detected when
+vmscan walks the reverse map in page_referenced() or try_to_unmap().  The page
+is culled to the unevictable list when it is released by the shrinker.
 
 To "cull" an unevictable page, vmscan simply puts the page back on the LRU list
 using putback_lru_page() - the inverse operation to isolate_lru_page() - after
 dropping the page lock.  Because the condition which makes the page unevictable
-may change once the page is unlocked, putback_lru_page() will recheck the
-unevictable state of a page that it places on the unevictable list.  If the
-page has become unevictable, putback_lru_page() removes it from the list and
-retries, including the page_unevictable() test.  Because such a race is a rare
-event and movement of pages onto the unevictable list should be rare, these
-extra evictabilty checks should not occur in the majority of calls to
-putback_lru_page().
+may change once the page is unlocked, __pagevec_lru_add_fn() will recheck the
+unevictable state of a page before placing it on the unevictable list.
 
 
 MLOCKED Pages
@@ -227,16 +224,25 @@ Nick posted his patch as an alternative to a patch posted by Christoph Lameter
 to achieve the same objective: hiding mlocked pages from vmscan.
 
 In Nick's patch, he used one of the struct page LRU list link fields as a count
-of VM_LOCKED VMAs that map the page.  This use of the link field for a count
-prevented the management of the pages on an LRU list, and thus mlocked pages
-were not migratable as isolate_lru_page() could not find them, and the LRU list
-link field was not available to the migration subsystem.
+of VM_LOCKED VMAs that map the page (Rik van Riel had the same idea three years
+earlier).  But this use of the link field for a count prevented the management
+of the pages on an LRU list, and thus mlocked pages were not migratable as
+isolate_lru_page() could not detect them, and the LRU list link field was not
+available to the migration subsystem.
 
-Nick resolved this by putting mlocked pages back on the lru list before
+Nick resolved this by putting mlocked pages back on the LRU list before
 attempting to isolate them, thus abandoning the count of VM_LOCKED VMAs.  When
 Nick's patch was integrated with the Unevictable LRU work, the count was
-replaced by walking the reverse map to determine whether any VM_LOCKED VMAs
-mapped the page.  More on this below.
+replaced by walking the reverse map when munlocking, to determine whether any
+other VM_LOCKED VMAs still mapped the page.
+
+However, walking the reverse map for each page when munlocking was ugly and
+inefficient, and could lead to catastrophic contention on a file's rmap lock,
+when many processes which had it mlocked were trying to exit.  In 5.18, the
+idea of keeping mlock_count in Unevictable LRU list link field was revived and
+put to work, without preventing the migration of mlocked pages.  This is why
+the "Unevictable LRU list" cannot be a linked list of pages now; but there was
+no use for that linked list anyway - though its size is maintained for meminfo.
 
 
 Basic Management
@@ -250,22 +256,18 @@ PageMlocked() functions.
 A PG_mlocked page will be placed on the unevictable list when it is added to
 the LRU.  Such pages can be "noticed" by memory management in several places:
 
- (1) in the mlock()/mlockall() system call handlers;
+ (1) in the mlock()/mlock2()/mlockall() system call handlers;
 
  (2) in the mmap() system call handler when mmapping a region with the
      MAP_LOCKED flag;
 
  (3) mmapping a region in a task that has called mlockall() with the MCL_FUTURE
-     flag
+     flag;
 
- (4) in the fault path, if mlocked pages are "culled" in the fault path,
-     and when a VM_LOCKED stack segment is expanded; or
+ (4) in the fault path and when a VM_LOCKED stack segment is expanded; or
 
  (5) as mentioned above, in vmscan:shrink_page_list() when attempting to
-     reclaim a page in a VM_LOCKED VMA via try_to_unmap()
-
-all of which result in the VM_LOCKED flag being set for the VMA if it doesn't
-already have it set.
+     reclaim a page in a VM_LOCKED VMA by page_referenced() or try_to_unmap().
 
 mlocked pages become unlocked and rescued from the unevictable list when:
 
@@ -280,51 +282,53 @@ mlocked pages become unlocked and rescued from the unevictable list when:
  (4) before a page is COW'd in a VM_LOCKED VMA.
 
 
-mlock()/mlockall() System Call Handling
----------------------------------------
+mlock()/mlock2()/mlockall() System Call Handling
+------------------------------------------------
 
-Both [do\_]mlock() and [do\_]mlockall() system call handlers call mlock_fixup()
+mlock(), mlock2() and mlockall() system call handlers proceed to mlock_fixup()
 for each VMA in the range specified by the call.  In the case of mlockall(),
 this is the entire active address space of the task.  Note that mlock_fixup()
 is used for both mlocking and munlocking a range of memory.  A call to mlock()
-an already VM_LOCKED VMA, or to munlock() a VMA that is not VM_LOCKED is
-treated as a no-op, and mlock_fixup() simply returns.
+an already VM_LOCKED VMA, or to munlock() a VMA that is not VM_LOCKED, is
+treated as a no-op and mlock_fixup() simply returns.
 
-If the VMA passes some filtering as described in "Filtering Special Vmas"
+If the VMA passes some filtering as described in "Filtering Special VMAs"
 below, mlock_fixup() will attempt to merge the VMA with its neighbors or split
-off a subset of the VMA if the range does not cover the entire VMA.  Once the
-VMA has been merged or split or neither, mlock_fixup() will call
-populate_vma_page_range() to fault in the pages via get_user_pages() and to
-mark the pages as mlocked via mlock_vma_page().
+off a subset of the VMA if the range does not cover the entire VMA.  Any pages
+already present in the VMA are then marked as mlocked by mlock_page() via
+mlock_pte_range() via walk_page_range() via mlock_vma_pages_range().
+
+Before returning from the system call, do_mlock() or mlockall() will call
+__mm_populate() to fault in the remaining pages via get_user_pages() and to
+mark those pages as mlocked as they are faulted.
 
 Note that the VMA being mlocked might be mapped with PROT_NONE.  In this case,
 get_user_pages() will be unable to fault in the pages.  That's okay.  If pages
-do end up getting faulted into this VM_LOCKED VMA, we'll handle them in the
-fault path or in vmscan.
-
-Also note that a page returned by get_user_pages() could be truncated or
-migrated out from under us, while we're trying to mlock it.  To detect this,
-populate_vma_page_range() checks page_mapping() after acquiring the page lock.
-If the page is still associated with its mapping, we'll go ahead and call
-mlock_vma_page().  If the mapping is gone, we just unlock the page and move on.
-In the worst case, this will result in a page mapped in a VM_LOCKED VMA
-remaining on a normal LRU list without being PageMlocked().  Again, vmscan will
-detect and cull such pages.
-
-mlock_vma_page() will call TestSetPageMlocked() for each page returned by
-get_user_pages().  We use TestSetPageMlocked() because the page might already
-be mlocked by another task/VMA and we don't want to do extra work.  We
-especially do not want to count an mlocked page more than once in the
-statistics.  If the page was already mlocked, mlock_vma_page() need do nothing
-more.
-
-If the page was NOT already mlocked, mlock_vma_page() attempts to isolate the
-page from the LRU, as it is likely on the appropriate active or inactive list
-at that time.  If the isolate_lru_page() succeeds, mlock_vma_page() will put
-back the page - by calling putback_lru_page() - which will notice that the page
-is now mlocked and divert the page to the node's unevictable list.  If
-mlock_vma_page() is unable to isolate the page from the LRU, vmscan will handle
-it later if and when it attempts to reclaim the page.
+do end up getting faulted into this VM_LOCKED VMA, they will be handled in the
+fault path - which is also how mlock2()'s MLOCK_ONFAULT areas are handled.
+
+For each PTE (or PMD) being faulted into a VMA, the page add rmap function
+calls mlock_vma_page(), which calls mlock_page() when the VMA is VM_LOCKED
+(unless it is a PTE mapping of a part of a transparent huge page).  Or when
+it is a newly allocated anonymous page, lru_cache_add_inactive_or_unevictable()
+calls mlock_new_page() instead: similar to mlock_page(), but can make better
+judgments, since this page is held exclusively and known not to be on LRU yet.
+
+mlock_page() sets PageMlocked immediately, then places the page on the CPU's
+mlock pagevec, to batch up the rest of the work to be done under lru_lock by
+__mlock_page().  __mlock_page() sets PageUnevictable, initializes mlock_count
+and moves the page to unevictable state ("the unevictable LRU", but with
+mlock_count in place of LRU threading).  Or if the page was already PageLRU
+and PageUnevictable and PageMlocked, it simply increments the mlock_count.
+
+But in practice that may not work ideally: the page may not yet be on an LRU, or
+it may have been temporarily isolated from LRU.  In such cases the mlock_count
+field cannot be touched, but will be set to 0 later when __pagevec_lru_add_fn()
+returns the page to "LRU".  Races prohibit mlock_count from being set to 1 then:
+rather than risk stranding a page indefinitely as unevictable, always err with
+mlock_count on the low side, so that when munlocked the page will be rescued to
+an evictable LRU, then perhaps be mlocked again later if vmscan finds it in a
+VM_LOCKED VMA.
 
 
 Filtering Special VMAs
@@ -339,68 +343,48 @@ mlock_fixup() filters several classes of "special" VMAs:
    so there is no sense in attempting to visit them.
 
 2) VMAs mapping hugetlbfs page are already effectively pinned into memory.  We
-   neither need nor want to mlock() these pages.  However, to preserve the
-   prior behavior of mlock() - before the unevictable/mlock changes -
-   mlock_fixup() will call make_pages_present() in the hugetlbfs VMA range to
-   allocate the huge pages and populate the ptes.
+   neither need nor want to mlock() these pages.  But __mm_populate() includes
+   hugetlbfs ranges, allocating the huge pages and populating the PTEs.
 
 3) VMAs with VM_DONTEXPAND are generally userspace mappings of kernel pages,
-   such as the VDSO page, relay channel pages, etc. These pages
-   are inherently unevictable and are not managed on the LRU lists.
-   mlock_fixup() treats these VMAs the same as hugetlbfs VMAs.  It calls
-   make_pages_present() to populate the ptes.
+   such as the VDSO page, relay channel pages, etc.  These pages are inherently
+   unevictable and are not managed on the LRU lists.  __mm_populate() includes
+   these ranges, populating the PTEs if not already populated.
+
+4) VMAs with VM_MIXEDMAP set are not marked VM_LOCKED, but __mm_populate()
+   includes these ranges, populating the PTEs if not already populated.
 
 Note that for all of these special VMAs, mlock_fixup() does not set the
 VM_LOCKED flag.  Therefore, we won't have to deal with them later during
 munlock(), munmap() or task exit.  Neither does mlock_fixup() account these
 VMAs against the task's "locked_vm".
 
-.. _munlock_munlockall_handling:
 
 munlock()/munlockall() System Call Handling
 -------------------------------------------
 
-The munlock() and munlockall() system calls are handled by the same functions -
-do_mlock[all]() - as the mlock() and mlockall() system calls with the unlock vs
-lock operation indicated by an argument.  So, these system calls are also
-handled by mlock_fixup().  Again, if called for an already munlocked VMA,
-mlock_fixup() simply returns.  Because of the VMA filtering discussed above,
-VM_LOCKED will not be set in any "special" VMAs.  So, these VMAs will be
-ignored for munlock.
+The munlock() and munlockall() system calls are handled by the same
+mlock_fixup() function as mlock(), mlock2() and mlockall() system calls are.
+If called to munlock an already munlocked VMA, mlock_fixup() simply returns.
+Because of the VMA filtering discussed above, VM_LOCKED will not be set in
+any "special" VMAs.  So, those VMAs will be ignored for munlock.
 
 If the VMA is VM_LOCKED, mlock_fixup() again attempts to merge or split off the
-specified range.  The range is then munlocked via the function
-populate_vma_page_range() - the same function used to mlock a VMA range -
-passing a flag to indicate that munlock() is being performed.
-
-Because the VMA access protections could have been changed to PROT_NONE after
-faulting in and mlocking pages, get_user_pages() was unreliable for visiting
-these pages for munlocking.  Because we don't want to leave pages mlocked,
-get_user_pages() was enhanced to accept a flag to ignore the permissions when
-fetching the pages - all of which should be resident as a result of previous
-mlocking.
-
-For munlock(), populate_vma_page_range() unlocks individual pages by calling
-munlock_vma_page().  munlock_vma_page() unconditionally clears the PG_mlocked
-flag using TestClearPageMlocked().  As with mlock_vma_page(),
-munlock_vma_page() use the Test*PageMlocked() function to handle the case where
-the page might have already been unlocked by another task.  If the page was
-mlocked, munlock_vma_page() updates that zone statistics for the number of
-mlocked pages.  Note, however, that at this point we haven't checked whether
-the page is mapped by other VM_LOCKED VMAs.
-
-We can't call page_mlock(), the function that walks the reverse map to
-check for other VM_LOCKED VMAs, without first isolating the page from the LRU.
-page_mlock() is a variant of try_to_unmap() and thus requires that the page
-not be on an LRU list [more on these below].  However, the call to
-isolate_lru_page() could fail, in which case we can't call page_mlock().  So,
-we go ahead and clear PG_mlocked up front, as this might be the only chance we
-have.  If we can successfully isolate the page, we go ahead and call
-page_mlock(), which will restore the PG_mlocked flag and update the zone
-page statistics if it finds another VMA holding the page mlocked.  If we fail
-to isolate the page, we'll have left a potentially mlocked page on the LRU.
-This is fine, because we'll catch it later if and if vmscan tries to reclaim
-the page.  This should be relatively rare.
+specified range.  All pages in the VMA are then munlocked by munlock_page() via
+mlock_pte_range() via walk_page_range() via mlock_vma_pages_range() - the same
+function used when mlocking a VMA range, with new flags for the VMA indicating
+that it is munlock() being performed.
+
+munlock_page() uses the mlock pagevec to batch up work to be done under
+lru_lock by  __munlock_page().  __munlock_page() decrements the page's
+mlock_count, and when that reaches 0 it clears PageMlocked and clears
+PageUnevictable, moving the page from unevictable state to inactive LRU.
+
+But in practice that may not work ideally: the page may not yet have reached
+"the unevictable LRU", or it may have been temporarily isolated from it.  In
+those cases its mlock_count field is unusable and must be assumed to be 0: so
+that the page will be rescued to an evictable LRU, then perhaps be mlocked
+again later if vmscan finds it in a VM_LOCKED VMA.
 
 
 Migrating MLOCKED Pages
@@ -410,33 +394,38 @@ A page that is being migrated has been isolated from the LRU lists and is held
 locked across unmapping of the page, updating the page's address space entry
 and copying the contents and state, until the page table entry has been
 replaced with an entry that refers to the new page.  Linux supports migration
-of mlocked pages and other unevictable pages.  This involves simply moving the
-PG_mlocked and PG_unevictable states from the old page to the new page.
+of mlocked pages and other unevictable pages.  PG_mlocked is cleared from the
+the old page when it is unmapped from the last VM_LOCKED VMA, and set when the
+new page is mapped in place of migration entry in a VM_LOCKED VMA.  If the page
+was unevictable because mlocked, PG_unevictable follows PG_mlocked; but if the
+page was unevictable for other reasons, PG_unevictable is copied explicitly.
 
 Note that page migration can race with mlocking or munlocking of the same page.
-This has been discussed from the mlock/munlock perspective in the respective
-sections above.  Both processes (migration and m[un]locking) hold the page
-locked.  This provides the first level of synchronization.  Page migration
-zeros out the page_mapping of the old page before unlocking it, so m[un]lock
-can skip these pages by testing the page mapping under page lock.
+There is mostly no problem since page migration requires unmapping all PTEs of
+the old page (including munlock where VM_LOCKED), then mapping in the new page
+(including mlock where VM_LOCKED).  The page table locks provide sufficient
+synchronization.
 
-To complete page migration, we place the new and old pages back onto the LRU
-after dropping the page lock.  The "unneeded" page - old page on success, new
-page on failure - will be freed when the reference count held by the migration
-process is released.  To ensure that we don't strand pages on the unevictable
-list because of a race between munlock and migration, page migration uses the
-putback_lru_page() function to add migrated pages back to the LRU.
+However, since mlock_vma_pages_range() starts by setting VM_LOCKED on a VMA,
+before mlocking any pages already present, if one of those pages were migrated
+before mlock_pte_range() reached it, it would get counted twice in mlock_count.
+To prevent that, mlock_vma_pages_range() temporarily marks the VMA as VM_IO,
+so that mlock_vma_page() will skip it.
+
+To complete page migration, we place the old and new pages back onto the LRU
+afterwards.  The "unneeded" page - old page on success, new page on failure -
+is freed when the reference count held by the migration process is released.
 
 
 Compacting MLOCKED Pages
 ------------------------
 
-The unevictable LRU can be scanned for compactable regions and the default
-behavior is to do so.  /proc/sys/vm/compact_unevictable_allowed controls
-this behavior (see Documentation/admin-guide/sysctl/vm.rst).  Once scanning of the
-unevictable LRU is enabled, the work of compaction is mostly handled by
-the page migration code and the same work flow as described in MIGRATING
-MLOCKED PAGES will apply.
+The memory map can be scanned for compactable regions and the default behavior
+is to let unevictable pages be moved.  /proc/sys/vm/compact_unevictable_allowed
+controls this behavior (see Documentation/admin-guide/sysctl/vm.rst).  The work
+of compaction is mostly handled by the page migration code and the same work
+flow as described in Migrating MLOCKED Pages will apply.
+
 
 MLOCKING Transparent Huge Pages
 -------------------------------
@@ -445,51 +434,44 @@ A transparent huge page is represented by a single entry on an LRU list.
 Therefore, we can only make unevictable an entire compound page, not
 individual subpages.
 
-If a user tries to mlock() part of a huge page, we want the rest of the
-page to be reclaimable.
+If a user tries to mlock() part of a huge page, and no user mlock()s the
+whole of the huge page, we want the rest of the page to be reclaimable.
 
 We cannot just split the page on partial mlock() as split_huge_page() can
-fail and new intermittent failure mode for the syscall is undesirable.
+fail and a new intermittent failure mode for the syscall is undesirable.
 
-We handle this by keeping PTE-mapped huge pages on normal LRU lists: the
-PMD on border of VM_LOCKED VMA will be split into PTE table.
+We handle this by keeping PTE-mlocked huge pages on evictable LRU lists:
+the PMD on the border of a VM_LOCKED VMA will be split into a PTE table.
 
-This way the huge page is accessible for vmscan. Under memory pressure the
+This way the huge page is accessible for vmscan.  Under memory pressure the
 page will be split, subpages which belong to VM_LOCKED VMAs will be moved
-to unevictable LRU and the rest can be reclaimed.
+to the unevictable LRU and the rest can be reclaimed.
+
+/proc/meminfo's Unevictable and Mlocked amounts do not include those parts
+of a transparent huge page which are mapped only by PTEs in VM_LOCKED VMAs.
 
-See also comment in follow_trans_huge_pmd().
 
 mmap(MAP_LOCKED) System Call Handling
 -------------------------------------
 
-In addition the mlock()/mlockall() system calls, an application can request
-that a region of memory be mlocked supplying the MAP_LOCKED flag to the mmap()
-call. There is one important and subtle difference here, though. mmap() + mlock()
-will fail if the range cannot be faulted in (e.g. because mm_populate fails)
-and returns with ENOMEM while mmap(MAP_LOCKED) will not fail. The mmaped
-area will still have properties of the locked area - aka. pages will not get
-swapped out - but major page faults to fault memory in might still happen.
+In addition to the mlock(), mlock2() and mlockall() system calls, an application
+can request that a region of memory be mlocked by supplying the MAP_LOCKED flag
+to the mmap() call.  There is one important and subtle difference here, though.
+mmap() + mlock() will fail if the range cannot be faulted in (e.g. because
+mm_populate fails) and returns with ENOMEM while mmap(MAP_LOCKED) will not fail.
+The mmaped area will still have properties of the locked area - pages will not
+get swapped out - but major page faults to fault memory in might still happen.
 
-Furthermore, any mmap() call or brk() call that expands the heap by a
-task that has previously called mlockall() with the MCL_FUTURE flag will result
+Furthermore, any mmap() call or brk() call that expands the heap by a task
+that has previously called mlockall() with the MCL_FUTURE flag will result
 in the newly mapped memory being mlocked.  Before the unevictable/mlock
-changes, the kernel simply called make_pages_present() to allocate pages and
-populate the page table.
+changes, the kernel simply called make_pages_present() to allocate pages
+and populate the page table.
 
-To mlock a range of memory under the unevictable/mlock infrastructure, the
-mmap() handler and task address space expansion functions call
+To mlock a range of memory under the unevictable/mlock infrastructure,
+the mmap() handler and task address space expansion functions call
 populate_vma_page_range() specifying the vma and the address range to mlock.
 
-The callers of populate_vma_page_range() will have already added the memory range
-to be mlocked to the task's "locked_vm".  To account for filtered VMAs,
-populate_vma_page_range() returns the number of pages NOT mlocked.  All of the
-callers then subtract a non-negative return value from the task's locked_vm.  A
-negative return value represent an error - for example, from get_user_pages()
-attempting to fault in a VMA with PROT_NONE access.  In this case, we leave the
-memory range accounted as locked_vm, as the protections could be changed later
-and pages allocated into that region.
-
 
 munmap()/exit()/exec() System Call Handling
 -------------------------------------------
@@ -500,81 +482,53 @@ munlock the pages if we're removing the last VM_LOCKED VMA that maps the pages.
 Before the unevictable/mlock changes, mlocking did not mark the pages in any
 way, so unmapping them required no processing.
 
-To munlock a range of memory under the unevictable/mlock infrastructure, the
-munmap() handler and task address space call tear down function
-munlock_vma_pages_all().  The name reflects the observation that one always
-specifies the entire VMA range when munlock()ing during unmap of a region.
-Because of the VMA filtering when mlocking() regions, only "normal" VMAs that
-actually contain mlocked pages will be passed to munlock_vma_pages_all().
-
-munlock_vma_pages_all() clears the VM_LOCKED VMA flag and, like mlock_fixup()
-for the munlock case, calls __munlock_vma_pages_range() to walk the page table
-for the VMA's memory range and munlock_vma_page() each resident page mapped by
-the VMA.  This effectively munlocks the page, only if this is the last
-VM_LOCKED VMA that maps the page.
-
-
-try_to_unmap()
---------------
-
-Pages can, of course, be mapped into multiple VMAs.  Some of these VMAs may
-have VM_LOCKED flag set.  It is possible for a page mapped into one or more
-VM_LOCKED VMAs not to have the PG_mlocked flag set and therefore reside on one
-of the active or inactive LRU lists.  This could happen if, for example, a task
-in the process of munlocking the page could not isolate the page from the LRU.
-As a result, vmscan/shrink_page_list() might encounter such a page as described
-in section "vmscan's handling of unevictable pages".  To handle this situation,
-try_to_unmap() checks for VM_LOCKED VMAs while it is walking a page's reverse
-map.
-
-try_to_unmap() is always called, by either vmscan for reclaim or for page
-migration, with the argument page locked and isolated from the LRU.  Separate
-functions handle anonymous and mapped file and KSM pages, as these types of
-pages have different reverse map lookup mechanisms, with different locking.
-In each case, whether rmap_walk_anon() or rmap_walk_file() or rmap_walk_ksm(),
-it will call try_to_unmap_one() for every VMA which might contain the page.
-
-When trying to reclaim, if try_to_unmap_one() finds the page in a VM_LOCKED
-VMA, it will then mlock the page via mlock_vma_page() instead of unmapping it,
-and return SWAP_MLOCK to indicate that the page is unevictable: and the scan
-stops there.
-
-mlock_vma_page() is called while holding the page table's lock (in addition
-to the page lock, and the rmap lock): to serialize against concurrent mlock or
-munlock or munmap system calls, mm teardown (munlock_vma_pages_all), reclaim,
-holepunching, and truncation of file pages and their anonymous COWed pages.
-
-
-page_mlock() Reverse Map Scan
----------------------------------
-
-When munlock_vma_page() [see section :ref:`munlock()/munlockall() System Call
-Handling <munlock_munlockall_handling>` above] tries to munlock a
-page, it needs to determine whether or not the page is mapped by any
-VM_LOCKED VMA without actually attempting to unmap all PTEs from the
-page.  For this purpose, the unevictable/mlock infrastructure
-introduced a variant of try_to_unmap() called page_mlock().
-
-page_mlock() walks the respective reverse maps looking for VM_LOCKED VMAs. When
-such a VMA is found the page is mlocked via mlock_vma_page(). This undoes the
-pre-clearing of the page's PG_mlocked done by munlock_vma_page.
-
-Note that page_mlock()'s reverse map walk must visit every VMA in a page's
-reverse map to determine that a page is NOT mapped into any VM_LOCKED VMA.
-However, the scan can terminate when it encounters a VM_LOCKED VMA.
-Although page_mlock() might be called a great many times when munlocking a
-large region or tearing down a large address space that has been mlocked via
-mlockall(), overall this is a fairly rare event.
+For each PTE (or PMD) being unmapped from a VMA, page_remove_rmap() calls
+munlock_vma_page(), which calls munlock_page() when the VMA is VM_LOCKED
+(unless it was a PTE mapping of a part of a transparent huge page).
+
+munlock_page() uses the mlock pagevec to batch up work to be done under
+lru_lock by  __munlock_page().  __munlock_page() decrements the page's
+mlock_count, and when that reaches 0 it clears PageMlocked and clears
+PageUnevictable, moving the page from unevictable state to inactive LRU.
+
+But in practice that may not work ideally: the page may not yet have reached
+"the unevictable LRU", or it may have been temporarily isolated from it.  In
+those cases its mlock_count field is unusable and must be assumed to be 0: so
+that the page will be rescued to an evictable LRU, then perhaps be mlocked
+again later if vmscan finds it in a VM_LOCKED VMA.
+
+
+Truncating MLOCKED Pages
+------------------------
+
+File truncation or hole punching forcibly unmaps the deleted pages from
+userspace; truncation even unmaps and deletes any private anonymous pages
+which had been Copied-On-Write from the file pages now being truncated.
+
+Mlocked pages can be munlocked and deleted in this way: like with munmap(),
+for each PTE (or PMD) being unmapped from a VMA, page_remove_rmap() calls
+munlock_vma_page(), which calls munlock_page() when the VMA is VM_LOCKED
+(unless it was a PTE mapping of a part of a transparent huge page).
+
+However, if there is a racing munlock(), since mlock_vma_pages_range() starts
+munlocking by clearing VM_LOCKED from a VMA, before munlocking all the pages
+present, if one of those pages were unmapped by truncation or hole punch before
+mlock_pte_range() reached it, it would not be recognized as mlocked by this VMA,
+and would not be counted out of mlock_count.  In this rare case, a page may
+still appear as PageMlocked after it has been fully unmapped: and it is left to
+release_pages() (or __page_cache_release()) to clear it and update statistics
+before freeing (this event is counted in /proc/vmstat unevictable_pgs_cleared,
+which is usually 0).
 
 
 Page Reclaim in shrink_*_list()
 -------------------------------
 
-shrink_active_list() culls any obviously unevictable pages - i.e.
-!page_evictable(page) - diverting these to the unevictable list.
+vmscan's shrink_active_list() culls any obviously unevictable pages -
+i.e. !page_evictable(page) pages - diverting those to the unevictable list.
 However, shrink_active_list() only sees unevictable pages that made it onto the
-active/inactive lru lists.  Note that these pages do not have PageUnevictable
-set - otherwise they would be on the unevictable list and shrink_active_list
+active/inactive LRU lists.  Note that these pages do not have PageUnevictable
+set - otherwise they would be on the unevictable list and shrink_active_list()
 would never see them.
 
 Some examples of these unevictable pages on the LRU lists are:
@@ -586,20 +540,15 @@ Some examples of these unevictable pages on the LRU lists are:
      when an application accesses the page the first time after SHM_LOCK'ing
      the segment.
 
- (3) mlocked pages that could not be isolated from the LRU and moved to the
-     unevictable list in mlock_vma_page().
-
-shrink_inactive_list() also diverts any unevictable pages that it finds on the
-inactive lists to the appropriate node's unevictable list.
+ (3) pages still mapped into VM_LOCKED VMAs, which should be marked mlocked,
+     but events left mlock_count too low, so they were munlocked too early.
 
-shrink_inactive_list() should only see SHM_LOCK'd pages that became SHM_LOCK'd
-after shrink_active_list() had moved them to the inactive list, or pages mapped
-into VM_LOCKED VMAs that munlock_vma_page() couldn't isolate from the LRU to
-recheck via page_mlock().  shrink_inactive_list() won't notice the latter,
-but will pass on to shrink_page_list().
+vmscan's shrink_inactive_list() and shrink_page_list() also divert obviously
+unevictable pages found on the inactive lists to the appropriate memory cgroup
+and node unevictable list.
 
-shrink_page_list() again culls obviously unevictable pages that it could
-encounter for similar reason to shrink_inactive_list().  Pages mapped into
-VM_LOCKED VMAs but without PG_mlocked set will make it all the way to
-try_to_unmap().  shrink_page_list() will divert them to the unevictable list
-when try_to_unmap() returns SWAP_MLOCK, as discussed above.
+rmap's page_referenced_one(), called via vmscan's shrink_active_list() or
+shrink_page_list(), and rmap's try_to_unmap_one() called via shrink_page_list(),
+check for (3) pages still mapped into VM_LOCKED VMAs, and call mlock_vma_page()
+to correct them.  Such pages are culled to the unevictable list when released
+by the shrinker.

fs/nilfs2/btnode.c

@@ -20,6 +20,23 @@
 #include "page.h"
 #include "btnode.h"
 
+
+/**
+ * nilfs_init_btnc_inode - initialize B-tree node cache inode
+ * @btnc_inode: inode to be initialized
+ *
+ * nilfs_init_btnc_inode() sets up an inode for B-tree node cache.
+ */
+void nilfs_init_btnc_inode(struct inode *btnc_inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(btnc_inode);
+
+	btnc_inode->i_mode = S_IFREG;
+	ii->i_flags = 0;
+	memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap));
+	mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS);
+}
+
 void nilfs_btnode_cache_clear(struct address_space *btnc)
 {
 	invalidate_mapping_pages(btnc, 0, -1);
@@ -29,7 +46,7 @@ void nilfs_btnode_cache_clear(struct address_space *btnc)
 struct buffer_head *
 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
 {
-	struct inode *inode = NILFS_BTNC_I(btnc);
+	struct inode *inode = btnc->host;
 	struct buffer_head *bh;
 
 	bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
@@ -57,7 +74,7 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
 			      struct buffer_head **pbh, sector_t *submit_ptr)
 {
 	struct buffer_head *bh;
-	struct inode *inode = NILFS_BTNC_I(btnc);
+	struct inode *inode = btnc->host;
 	struct page *page;
 	int err;
 
@@ -157,7 +174,7 @@ int nilfs_btnode_prepare_change_key(struct address_space *btnc,
 				    struct nilfs_btnode_chkey_ctxt *ctxt)
 {
 	struct buffer_head *obh, *nbh;
-	struct inode *inode = NILFS_BTNC_I(btnc);
+	struct inode *inode = btnc->host;
 	__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 	int err;
 

fs/nilfs2/btnode.h

@@ -30,6 +30,7 @@ struct nilfs_btnode_chkey_ctxt {
 	struct buffer_head *newbh;
 };
 
+void nilfs_init_btnc_inode(struct inode *btnc_inode);
 void nilfs_btnode_cache_clear(struct address_space *);
 struct buffer_head *nilfs_btnode_create_block(struct address_space *btnc,
 					      __u64 blocknr);

fs/nilfs2/btree.c

@@ -58,7 +58,8 @@ static void nilfs_btree_free_path(struct nilfs_btree_path *path)
 static int nilfs_btree_get_new_block(const struct nilfs_bmap *btree,
 				     __u64 ptr, struct buffer_head **bhp)
 {
-	struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
+	struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
+	struct address_space *btnc = btnc_inode->i_mapping;
 	struct buffer_head *bh;
 
 	bh = nilfs_btnode_create_block(btnc, ptr);
@@ -470,7 +471,8 @@ static int __nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
 				   struct buffer_head **bhp,
 				   const struct nilfs_btree_readahead_info *ra)
 {
-	struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
+	struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
+	struct address_space *btnc = btnc_inode->i_mapping;
 	struct buffer_head *bh, *ra_bh;
 	sector_t submit_ptr = 0;
 	int ret;
@@ -1741,6 +1743,10 @@ nilfs_btree_prepare_convert_and_insert(struct nilfs_bmap *btree, __u64 key,
 		dat = nilfs_bmap_get_dat(btree);
 	}
 
+	ret = nilfs_attach_btree_node_cache(&NILFS_BMAP_I(btree)->vfs_inode);
+	if (ret < 0)
+		return ret;
+
 	ret = nilfs_bmap_prepare_alloc_ptr(btree, dreq, dat);
 	if (ret < 0)
 		return ret;
@@ -1913,7 +1919,7 @@ static int nilfs_btree_prepare_update_v(struct nilfs_bmap *btree,
 		path[level].bp_ctxt.newkey = path[level].bp_newreq.bpr_ptr;
 		path[level].bp_ctxt.bh = path[level].bp_bh;
 		ret = nilfs_btnode_prepare_change_key(
-			&NILFS_BMAP_I(btree)->i_btnode_cache,
+			NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
 			&path[level].bp_ctxt);
 		if (ret < 0) {
 			nilfs_dat_abort_update(dat,
@@ -1939,7 +1945,7 @@ static void nilfs_btree_commit_update_v(struct nilfs_bmap *btree,
 
 	if (buffer_nilfs_node(path[level].bp_bh)) {
 		nilfs_btnode_commit_change_key(
-			&NILFS_BMAP_I(btree)->i_btnode_cache,
+			NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
 			&path[level].bp_ctxt);
 		path[level].bp_bh = path[level].bp_ctxt.bh;
 	}
@@ -1958,7 +1964,7 @@ static void nilfs_btree_abort_update_v(struct nilfs_bmap *btree,
 			       &path[level].bp_newreq.bpr_req);
 	if (buffer_nilfs_node(path[level].bp_bh))
 		nilfs_btnode_abort_change_key(
-			&NILFS_BMAP_I(btree)->i_btnode_cache,
+			NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
 			&path[level].bp_ctxt);
 }
 
@@ -2134,7 +2140,8 @@ static void nilfs_btree_add_dirty_buffer(struct nilfs_bmap *btree,
 static void nilfs_btree_lookup_dirty_buffers(struct nilfs_bmap *btree,
 					     struct list_head *listp)
 {
-	struct address_space *btcache = &NILFS_BMAP_I(btree)->i_btnode_cache;
+	struct inode *btnc_inode = NILFS_BMAP_I(btree)->i_assoc_inode;
+	struct address_space *btcache = btnc_inode->i_mapping;
 	struct list_head lists[NILFS_BTREE_LEVEL_MAX];
 	struct pagevec pvec;
 	struct buffer_head *bh, *head;
@@ -2188,12 +2195,12 @@ static int nilfs_btree_assign_p(struct nilfs_bmap *btree,
 		path[level].bp_ctxt.newkey = blocknr;
 		path[level].bp_ctxt.bh = *bh;
 		ret = nilfs_btnode_prepare_change_key(
-			&NILFS_BMAP_I(btree)->i_btnode_cache,
+			NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
 			&path[level].bp_ctxt);
 		if (ret < 0)
 			return ret;
 		nilfs_btnode_commit_change_key(
-			&NILFS_BMAP_I(btree)->i_btnode_cache,
+			NILFS_BMAP_I(btree)->i_assoc_inode->i_mapping,
 			&path[level].bp_ctxt);
 		*bh = path[level].bp_ctxt.bh;
 	}
@@ -2398,6 +2405,10 @@ int nilfs_btree_init(struct nilfs_bmap *bmap)
 
 	if (nilfs_btree_root_broken(nilfs_btree_get_root(bmap), bmap->b_inode))
 		ret = -EIO;
+	else
+		ret = nilfs_attach_btree_node_cache(
+			&NILFS_BMAP_I(bmap)->vfs_inode);
+
 	return ret;
 }
 

fs/nilfs2/dat.c

@@ -497,7 +497,9 @@ int nilfs_dat_read(struct super_block *sb, size_t entry_size,
 	di = NILFS_DAT_I(dat);
 	lockdep_set_class(&di->mi.mi_sem, &dat_lock_key);
 	nilfs_palloc_setup_cache(dat, &di->palloc_cache);
-	nilfs_mdt_setup_shadow_map(dat, &di->shadow);
+	err = nilfs_mdt_setup_shadow_map(dat, &di->shadow);
+	if (err)
+		goto failed;
 
 	err = nilfs_read_inode_common(dat, raw_inode);
 	if (err)

fs/nilfs2/gcinode.c

@@ -126,9 +126,10 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
 int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
 				   __u64 vbn, struct buffer_head **out_bh)
 {
+	struct inode *btnc_inode = NILFS_I(inode)->i_assoc_inode;
 	int ret;
 
-	ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
+	ret = nilfs_btnode_submit_block(btnc_inode->i_mapping,
 					vbn ? : pbn, pbn, REQ_OP_READ, 0,
 					out_bh, &pbn);
 	if (ret == -EEXIST) /* internal code (cache hit) */
@@ -170,7 +171,7 @@ int nilfs_init_gcinode(struct inode *inode)
 	ii->i_flags = 0;
 	nilfs_bmap_init_gc(ii->i_bmap);
 
-	return 0;
+	return nilfs_attach_btree_node_cache(inode);
 }
 
 /**
@@ -185,7 +186,7 @@ void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs)
 		ii = list_first_entry(head, struct nilfs_inode_info, i_dirty);
 		list_del_init(&ii->i_dirty);
 		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
-		nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+		nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
 		iput(&ii->vfs_inode);
 	}
 }

fs/nilfs2/inode.c

@@ -29,12 +29,16 @@
  * @cno: checkpoint number
  * @root: pointer on NILFS root object (mounted checkpoint)
  * @for_gc: inode for GC flag
+ * @for_btnc: inode for B-tree node cache flag
+ * @for_shadow: inode for shadowed page cache flag
  */
 struct nilfs_iget_args {
 	u64 ino;
 	__u64 cno;
 	struct nilfs_root *root;
-	int for_gc;
+	bool for_gc;
+	bool for_btnc;
+	bool for_shadow;
 };
 
 static int nilfs_iget_test(struct inode *inode, void *opaque);
@@ -312,7 +316,8 @@ static int nilfs_insert_inode_locked(struct inode *inode,
 				     unsigned long ino)
 {
 	struct nilfs_iget_args args = {
-		.ino = ino, .root = root, .cno = 0, .for_gc = 0
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
 	};
 
 	return insert_inode_locked4(inode, ino, nilfs_iget_test, &args);
@@ -525,6 +530,19 @@ static int nilfs_iget_test(struct inode *inode, void *opaque)
 		return 0;
 
 	ii = NILFS_I(inode);
+	if (test_bit(NILFS_I_BTNC, &ii->i_state)) {
+		if (!args->for_btnc)
+			return 0;
+	} else if (args->for_btnc) {
+		return 0;
+	}
+	if (test_bit(NILFS_I_SHADOW, &ii->i_state)) {
+		if (!args->for_shadow)
+			return 0;
+	} else if (args->for_shadow) {
+		return 0;
+	}
+
 	if (!test_bit(NILFS_I_GCINODE, &ii->i_state))
 		return !args->for_gc;
 
@@ -536,15 +554,17 @@ static int nilfs_iget_set(struct inode *inode, void *opaque)
 	struct nilfs_iget_args *args = opaque;
 
 	inode->i_ino = args->ino;
-	if (args->for_gc) {
+	NILFS_I(inode)->i_cno = args->cno;
+	NILFS_I(inode)->i_root = args->root;
+	if (args->root && args->ino == NILFS_ROOT_INO)
+		nilfs_get_root(args->root);
+
+	if (args->for_gc)
 		NILFS_I(inode)->i_state = BIT(NILFS_I_GCINODE);
-		NILFS_I(inode)->i_cno = args->cno;
-		NILFS_I(inode)->i_root = NULL;
-	} else {
-		if (args->root && args->ino == NILFS_ROOT_INO)
-			nilfs_get_root(args->root);
-		NILFS_I(inode)->i_root = args->root;
-	}
+	if (args->for_btnc)
+		NILFS_I(inode)->i_state |= BIT(NILFS_I_BTNC);
+	if (args->for_shadow)
+		NILFS_I(inode)->i_state |= BIT(NILFS_I_SHADOW);
 	return 0;
 }
 
@@ -552,7 +572,8 @@ struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
 			    unsigned long ino)
 {
 	struct nilfs_iget_args args = {
-		.ino = ino, .root = root, .cno = 0, .for_gc = 0
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
 	};
 
 	return ilookup5(sb, ino, nilfs_iget_test, &args);
@@ -562,7 +583,8 @@ struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
 				unsigned long ino)
 {
 	struct nilfs_iget_args args = {
-		.ino = ino, .root = root, .cno = 0, .for_gc = 0
+		.ino = ino, .root = root, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = false
 	};
 
 	return iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
@@ -593,7 +615,8 @@ struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
 				__u64 cno)
 {
 	struct nilfs_iget_args args = {
-		.ino = ino, .root = NULL, .cno = cno, .for_gc = 1
+		.ino = ino, .root = NULL, .cno = cno, .for_gc = true,
+		.for_btnc = false, .for_shadow = false
 	};
 	struct inode *inode;
 	int err;
@@ -613,6 +636,113 @@ struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
 	return inode;
 }
 
+/**
+ * nilfs_attach_btree_node_cache - attach a B-tree node cache to the inode
+ * @inode: inode object
+ *
+ * nilfs_attach_btree_node_cache() attaches a B-tree node cache to @inode,
+ * or does nothing if the inode already has it.  This function allocates
+ * an additional inode to maintain page cache of B-tree nodes one-on-one.
+ *
+ * Return Value: On success, 0 is returned. On errors, one of the following
+ * negative error code is returned.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ */
+int nilfs_attach_btree_node_cache(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct inode *btnc_inode;
+	struct nilfs_iget_args args;
+
+	if (ii->i_assoc_inode)
+		return 0;
+
+	args.ino = inode->i_ino;
+	args.root = ii->i_root;
+	args.cno = ii->i_cno;
+	args.for_gc = test_bit(NILFS_I_GCINODE, &ii->i_state) != 0;
+	args.for_btnc = true;
+	args.for_shadow = test_bit(NILFS_I_SHADOW, &ii->i_state) != 0;
+
+	btnc_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
+				  nilfs_iget_set, &args);
+	if (unlikely(!btnc_inode))
+		return -ENOMEM;
+	if (btnc_inode->i_state & I_NEW) {
+		nilfs_init_btnc_inode(btnc_inode);
+		unlock_new_inode(btnc_inode);
+	}
+	NILFS_I(btnc_inode)->i_assoc_inode = inode;
+	NILFS_I(btnc_inode)->i_bmap = ii->i_bmap;
+	ii->i_assoc_inode = btnc_inode;
+
+	return 0;
+}
+
+/**
+ * nilfs_detach_btree_node_cache - detach the B-tree node cache from the inode
+ * @inode: inode object
+ *
+ * nilfs_detach_btree_node_cache() detaches the B-tree node cache and its
+ * holder inode bound to @inode, or does nothing if @inode doesn't have it.
+ */
+void nilfs_detach_btree_node_cache(struct inode *inode)
+{
+	struct nilfs_inode_info *ii = NILFS_I(inode);
+	struct inode *btnc_inode = ii->i_assoc_inode;
+
+	if (btnc_inode) {
+		NILFS_I(btnc_inode)->i_assoc_inode = NULL;
+		ii->i_assoc_inode = NULL;
+		iput(btnc_inode);
+	}
+}
+
+/**
+ * nilfs_iget_for_shadow - obtain inode for shadow mapping
+ * @inode: inode object that uses shadow mapping
+ *
+ * nilfs_iget_for_shadow() allocates a pair of inodes that holds page
+ * caches for shadow mapping.  The page cache for data pages is set up
+ * in one inode and the one for b-tree node pages is set up in the
+ * other inode, which is attached to the former inode.
+ *
+ * Return Value: On success, a pointer to the inode for data pages is
+ * returned. On errors, one of the following negative error code is returned
+ * in a pointer type.
+ *
+ * %-ENOMEM - Insufficient memory available.
+ */
+struct inode *nilfs_iget_for_shadow(struct inode *inode)
+{
+	struct nilfs_iget_args args = {
+		.ino = inode->i_ino, .root = NULL, .cno = 0, .for_gc = false,
+		.for_btnc = false, .for_shadow = true
+	};
+	struct inode *s_inode;
+	int err;
+
+	s_inode = iget5_locked(inode->i_sb, inode->i_ino, nilfs_iget_test,
+			       nilfs_iget_set, &args);
+	if (unlikely(!s_inode))
+		return ERR_PTR(-ENOMEM);
+	if (!(s_inode->i_state & I_NEW))
+		return inode;
+
+	NILFS_I(s_inode)->i_flags = 0;
+	memset(NILFS_I(s_inode)->i_bmap, 0, sizeof(struct nilfs_bmap));
+	mapping_set_gfp_mask(s_inode->i_mapping, GFP_NOFS);
+
+	err = nilfs_attach_btree_node_cache(s_inode);
+	if (unlikely(err)) {
+		iget_failed(s_inode);
+		return ERR_PTR(err);
+	}
+	unlock_new_inode(s_inode);
+	return s_inode;
+}
+
 void nilfs_write_inode_common(struct inode *inode,
 			      struct nilfs_inode *raw_inode, int has_bmap)
 {
@@ -760,7 +890,8 @@ static void nilfs_clear_inode(struct inode *inode)
 	if (test_bit(NILFS_I_BMAP, &ii->i_state))
 		nilfs_bmap_clear(ii->i_bmap);
 
-	nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+	if (!test_bit(NILFS_I_BTNC, &ii->i_state))
+		nilfs_detach_btree_node_cache(inode);
 
 	if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
 		nilfs_put_root(ii->i_root);

fs/nilfs2/mdt.c

@@ -471,9 +471,18 @@ int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz)
 void nilfs_mdt_clear(struct inode *inode)
 {
 	struct nilfs_mdt_info *mdi = NILFS_MDT(inode);
+	struct nilfs_shadow_map *shadow = mdi->mi_shadow;
 
 	if (mdi->mi_palloc_cache)
 		nilfs_palloc_destroy_cache(inode);
+
+	if (shadow) {
+		struct inode *s_inode = shadow->inode;
+
+		shadow->inode = NULL;
+		iput(s_inode);
+		mdi->mi_shadow = NULL;
+	}
 }
 
 /**
@@ -507,12 +516,15 @@ int nilfs_mdt_setup_shadow_map(struct inode *inode,
 			       struct nilfs_shadow_map *shadow)
 {
 	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
+	struct inode *s_inode;
 
 	INIT_LIST_HEAD(&shadow->frozen_buffers);
-	address_space_init_once(&shadow->frozen_data);
-	nilfs_mapping_init(&shadow->frozen_data, inode);
-	address_space_init_once(&shadow->frozen_btnodes);
-	nilfs_mapping_init(&shadow->frozen_btnodes, inode);
+
+	s_inode = nilfs_iget_for_shadow(inode);
+	if (IS_ERR(s_inode))
+		return PTR_ERR(s_inode);
+
+	shadow->inode = s_inode;
 	mi->mi_shadow = shadow;
 	return 0;
 }
@@ -526,14 +538,15 @@ int nilfs_mdt_save_to_shadow_map(struct inode *inode)
 	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
 	struct nilfs_inode_info *ii = NILFS_I(inode);
 	struct nilfs_shadow_map *shadow = mi->mi_shadow;
+	struct inode *s_inode = shadow->inode;
 	int ret;
 
-	ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
+	ret = nilfs_copy_dirty_pages(s_inode->i_mapping, inode->i_mapping);
 	if (ret)
 		goto out;
 
-	ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
-				     &ii->i_btnode_cache);
+	ret = nilfs_copy_dirty_pages(NILFS_I(s_inode)->i_assoc_inode->i_mapping,
+				     ii->i_assoc_inode->i_mapping);
 	if (ret)
 		goto out;
 
@@ -549,7 +562,7 @@ int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh)
 	struct page *page;
 	int blkbits = inode->i_blkbits;
 
-	page = grab_cache_page(&shadow->frozen_data, bh->b_page->index);
+	page = grab_cache_page(shadow->inode->i_mapping, bh->b_page->index);
 	if (!page)
 		return -ENOMEM;
 
@@ -581,7 +594,7 @@ nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh)
 	struct page *page;
 	int n;
 
-	page = find_lock_page(&shadow->frozen_data, bh->b_page->index);
+	page = find_lock_page(shadow->inode->i_mapping, bh->b_page->index);
 	if (page) {
 		if (page_has_buffers(page)) {
 			n = bh_offset(bh) >> inode->i_blkbits;
@@ -622,10 +635,11 @@ void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
 		nilfs_palloc_clear_cache(inode);
 
 	nilfs_clear_dirty_pages(inode->i_mapping, true);
-	nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
+	nilfs_copy_back_pages(inode->i_mapping, shadow->inode->i_mapping);
 
-	nilfs_clear_dirty_pages(&ii->i_btnode_cache, true);
-	nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
+	nilfs_clear_dirty_pages(ii->i_assoc_inode->i_mapping, true);
+	nilfs_copy_back_pages(ii->i_assoc_inode->i_mapping,
+			      NILFS_I(shadow->inode)->i_assoc_inode->i_mapping);
 
 	nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
 
@@ -640,10 +654,11 @@ void nilfs_mdt_clear_shadow_map(struct inode *inode)
 {
 	struct nilfs_mdt_info *mi = NILFS_MDT(inode);
 	struct nilfs_shadow_map *shadow = mi->mi_shadow;
+	struct inode *shadow_btnc_inode = NILFS_I(shadow->inode)->i_assoc_inode;
 
 	down_write(&mi->mi_sem);
 	nilfs_release_frozen_buffers(shadow);
-	truncate_inode_pages(&shadow->frozen_data, 0);
-	truncate_inode_pages(&shadow->frozen_btnodes, 0);
+	truncate_inode_pages(shadow->inode->i_mapping, 0);
+	truncate_inode_pages(shadow_btnc_inode->i_mapping, 0);
 	up_write(&mi->mi_sem);
 }

fs/nilfs2/mdt.h

@@ -18,14 +18,12 @@
 /**
  * struct nilfs_shadow_map - shadow mapping of meta data file
  * @bmap_store: shadow copy of bmap state
- * @frozen_data: shadowed dirty data pages
- * @frozen_btnodes: shadowed dirty b-tree nodes' pages
+ * @inode: holder of page caches used in shadow mapping
  * @frozen_buffers: list of frozen buffers
  */
 struct nilfs_shadow_map {
 	struct nilfs_bmap_store bmap_store;
-	struct address_space frozen_data;
-	struct address_space frozen_btnodes;
+	struct inode *inode;
 	struct list_head frozen_buffers;
 };
 

fs/nilfs2/nilfs.h

@@ -28,7 +28,7 @@
  * @i_xattr: <TODO>
  * @i_dir_start_lookup: page index of last successful search
  * @i_cno: checkpoint number for GC inode
- * @i_btnode_cache: cached pages of b-tree nodes
+ * @i_assoc_inode: associated inode (B-tree node cache holder or back pointer)
  * @i_dirty: list for connecting dirty files
  * @xattr_sem: semaphore for extended attributes processing
  * @i_bh: buffer contains disk inode
@@ -43,7 +43,7 @@ struct nilfs_inode_info {
 	__u64 i_xattr;	/* sector_t ??? */
 	__u32 i_dir_start_lookup;
 	__u64 i_cno;		/* check point number for GC inode */
-	struct address_space i_btnode_cache;
+	struct inode *i_assoc_inode;
 	struct list_head i_dirty;	/* List for connecting dirty files */
 
 #ifdef CONFIG_NILFS_XATTR
@@ -75,13 +75,6 @@ NILFS_BMAP_I(const struct nilfs_bmap *bmap)
 	return container_of(bmap, struct nilfs_inode_info, i_bmap_data);
 }
 
-static inline struct inode *NILFS_BTNC_I(struct address_space *btnc)
-{
-	struct nilfs_inode_info *ii =
-		container_of(btnc, struct nilfs_inode_info, i_btnode_cache);
-	return &ii->vfs_inode;
-}
-
 /*
  * Dynamic state flags of NILFS on-memory inode (i_state)
  */
@@ -98,6 +91,8 @@ enum {
 	NILFS_I_INODE_SYNC,		/* dsync is not allowed for inode */
 	NILFS_I_BMAP,			/* has bmap and btnode_cache */
 	NILFS_I_GCINODE,		/* inode for GC, on memory only */
+	NILFS_I_BTNC,			/* inode for btree node cache */
+	NILFS_I_SHADOW,			/* inode for shadowed page cache */
 };
 
 /*
@@ -267,6 +262,9 @@ struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
 			 unsigned long ino);
 extern struct inode *nilfs_iget_for_gc(struct super_block *sb,
 				       unsigned long ino, __u64 cno);
+int nilfs_attach_btree_node_cache(struct inode *inode);
+void nilfs_detach_btree_node_cache(struct inode *inode);
+struct inode *nilfs_iget_for_shadow(struct inode *inode);
 extern void nilfs_update_inode(struct inode *, struct buffer_head *, int);
 extern void nilfs_truncate(struct inode *);
 extern void nilfs_evict_inode(struct inode *);

fs/nilfs2/page.c

@@ -436,22 +436,12 @@ unsigned int nilfs_page_count_clean_buffers(struct page *page,
 	return nc;
 }
 
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
-{
-	mapping->host = inode;
-	mapping->flags = 0;
-	mapping_set_gfp_mask(mapping, GFP_NOFS);
-	mapping->private_data = NULL;
-	mapping->a_ops = &empty_aops;
-}
-
 /*
  * NILFS2 needs clear_page_dirty() in the following two cases:
  *
- * 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
- *    page dirty flags when it copies back pages from the shadow cache
- *    (gcdat->{i_mapping,i_btnode_cache}) to its original cache
- *    (dat->{i_mapping,i_btnode_cache}).
+ * 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
+ *    flag of pages when it copies back pages from shadow cache to the
+ *    original cache.
  *
  * 2) Some B-tree operations like insertion or deletion may dispose buffers
  *    in dirty state, and this needs to cancel the dirty state of their pages.

fs/nilfs2/page.h

@@ -43,7 +43,6 @@ int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
 void nilfs_copy_back_pages(struct address_space *, struct address_space *);
 void nilfs_clear_dirty_page(struct page *, bool);
 void nilfs_clear_dirty_pages(struct address_space *, bool);
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode);
 unsigned int nilfs_page_count_clean_buffers(struct page *, unsigned int,
 					    unsigned int);
 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,

fs/nilfs2/segment.c

@@ -733,15 +733,18 @@ static void nilfs_lookup_dirty_node_buffers(struct inode *inode,
 					    struct list_head *listp)
 {
 	struct nilfs_inode_info *ii = NILFS_I(inode);
-	struct address_space *mapping = &ii->i_btnode_cache;
+	struct inode *btnc_inode = ii->i_assoc_inode;
 	struct pagevec pvec;
 	struct buffer_head *bh, *head;
 	unsigned int i;
 	pgoff_t index = 0;
 
+	if (!btnc_inode)
+		return;
+
 	pagevec_init(&pvec);
 
-	while (pagevec_lookup_tag(&pvec, mapping, &index,
+	while (pagevec_lookup_tag(&pvec, btnc_inode->i_mapping, &index,
 					PAGECACHE_TAG_DIRTY)) {
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			bh = head = page_buffers(pvec.pages[i]);
@@ -2410,7 +2413,7 @@ nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
 			continue;
 		list_del_init(&ii->i_dirty);
 		truncate_inode_pages(&ii->vfs_inode.i_data, 0);
-		nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+		nilfs_btnode_cache_clear(ii->i_assoc_inode->i_mapping);
 		iput(&ii->vfs_inode);
 	}
 }

fs/nilfs2/super.c

@@ -157,7 +157,8 @@ struct inode *nilfs_alloc_inode(struct super_block *sb)
 	ii->i_bh = NULL;
 	ii->i_state = 0;
 	ii->i_cno = 0;
-	nilfs_mapping_init(&ii->i_btnode_cache, &ii->vfs_inode);
+	ii->i_assoc_inode = NULL;
+	ii->i_bmap = &ii->i_bmap_data;
 	return &ii->vfs_inode;
 }
 
@@ -1377,8 +1378,6 @@ static void nilfs_inode_init_once(void *obj)
 #ifdef CONFIG_NILFS_XATTR
 	init_rwsem(&ii->xattr_sem);
 #endif
-	address_space_init_once(&ii->i_btnode_cache);
-	ii->i_bmap = &ii->i_bmap_data;
 	inode_init_once(&ii->vfs_inode);
 }
 

fs/ocfs2/quota_global.c

@@ -337,7 +337,6 @@ void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex)
 /* Read information header from global quota file */
 int ocfs2_global_read_info(struct super_block *sb, int type)
 {
-	struct inode *gqinode = NULL;
 	unsigned int ino[OCFS2_MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE,
 					      GROUP_QUOTA_SYSTEM_INODE };
 	struct ocfs2_global_disk_dqinfo dinfo;
@@ -346,29 +345,31 @@ int ocfs2_global_read_info(struct super_block *sb, int type)
 	u64 pcount;
 	int status;
 
+	oinfo->dqi_gi.dqi_sb = sb;
+	oinfo->dqi_gi.dqi_type = type;
+	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
+	oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
+	oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
+	oinfo->dqi_gqi_bh = NULL;
+	oinfo->dqi_gqi_count = 0;
+
 	/* Read global header */
-	gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
+	oinfo->dqi_gqinode = ocfs2_get_system_file_inode(OCFS2_SB(sb), ino[type],
 			OCFS2_INVALID_SLOT);
-	if (!gqinode) {
+	if (!oinfo->dqi_gqinode) {
 		mlog(ML_ERROR, "failed to get global quota inode (type=%d)\n",
 			type);
 		status = -EINVAL;
 		goto out_err;
 	}
-	oinfo->dqi_gi.dqi_sb = sb;
-	oinfo->dqi_gi.dqi_type = type;
-	oinfo->dqi_gi.dqi_entry_size = sizeof(struct ocfs2_global_disk_dqblk);
-	oinfo->dqi_gi.dqi_ops = &ocfs2_global_ops;
-	oinfo->dqi_gqi_bh = NULL;
-	oinfo->dqi_gqi_count = 0;
-	oinfo->dqi_gqinode = gqinode;
+
 	status = ocfs2_lock_global_qf(oinfo, 0);
 	if (status < 0) {
 		mlog_errno(status);
 		goto out_err;
 	}
 
-	status = ocfs2_extent_map_get_blocks(gqinode, 0, &oinfo->dqi_giblk,
+	status = ocfs2_extent_map_get_blocks(oinfo->dqi_gqinode, 0, &oinfo->dqi_giblk,
 					     &pcount, NULL);
 	if (status < 0)
 		goto out_unlock;

fs/ocfs2/quota_local.c

@@ -702,8 +702,6 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
 	info->dqi_priv = oinfo;
 	oinfo->dqi_type = type;
 	INIT_LIST_HEAD(&oinfo->dqi_chunk);
-	oinfo->dqi_gqinode = NULL;
-	ocfs2_qinfo_lock_res_init(&oinfo->dqi_gqlock, oinfo);
 	oinfo->dqi_rec = NULL;
 	oinfo->dqi_lqi_bh = NULL;
 	oinfo->dqi_libh = NULL;

include/linux/gfp.h

@@ -264,9 +264,7 @@ struct vm_area_struct;
 #define __GFP_NOLOCKDEP ((__force gfp_t)___GFP_NOLOCKDEP)
 
 /* Room for N __GFP_FOO bits */
-#define __GFP_BITS_SHIFT (24 +						\
-			  3 * IS_ENABLED(CONFIG_KASAN_HW_TAGS) +	\
-			  IS_ENABLED(CONFIG_LOCKDEP))
+#define __GFP_BITS_SHIFT (27 + IS_ENABLED(CONFIG_LOCKDEP))
 #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
 
 /**

mm/damon/core.c

@@ -1019,12 +1019,15 @@ static int kdamond_wait_activation(struct damon_ctx *ctx)
 	struct damos *s;
 	unsigned long wait_time;
 	unsigned long min_wait_time = 0;
+	bool init_wait_time = false;
 
 	while (!kdamond_need_stop(ctx)) {
 		damon_for_each_scheme(s, ctx) {
 			wait_time = damos_wmark_wait_us(s);
-			if (!min_wait_time || wait_time < min_wait_time)
+			if (!init_wait_time || wait_time < min_wait_time) {
+				init_wait_time = true;
 				min_wait_time = wait_time;
+			}
 		}
 		if (!min_wait_time)
 			return 0;

mm/gup.c

@@ -1404,6 +1404,7 @@ long populate_vma_page_range(struct vm_area_struct *vma,
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long nr_pages = (end - start) / PAGE_SIZE;
 	int gup_flags;
+	long ret;
 
 	VM_BUG_ON(!PAGE_ALIGNED(start));
 	VM_BUG_ON(!PAGE_ALIGNED(end));
@@ -1438,8 +1439,10 @@ long populate_vma_page_range(struct vm_area_struct *vma,
 	 * We made sure addr is within a VMA, so the following will
 	 * not result in a stack expansion that recurses back here.
 	 */
-	return __get_user_pages(mm, start, nr_pages, gup_flags,
+	ret = __get_user_pages(mm, start, nr_pages, gup_flags,
 				NULL, NULL, locked);
+	lru_add_drain();
+	return ret;
 }
 
 /*
@@ -1471,6 +1474,7 @@ long faultin_vma_page_range(struct vm_area_struct *vma, unsigned long start,
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long nr_pages = (end - start) / PAGE_SIZE;
 	int gup_flags;
+	long ret;
 
 	VM_BUG_ON(!PAGE_ALIGNED(start));
 	VM_BUG_ON(!PAGE_ALIGNED(end));
@@ -1498,8 +1502,10 @@ long faultin_vma_page_range(struct vm_area_struct *vma, unsigned long start,
 	if (check_vma_flags(vma, gup_flags))
 		return -EINVAL;
 
-	return __get_user_pages(mm, start, nr_pages, gup_flags,
+	ret = __get_user_pages(mm, start, nr_pages, gup_flags,
 				NULL, NULL, locked);
+	lru_add_drain();
+	return ret;
 }
 
 /*

mm/internal.h

@@ -456,7 +456,8 @@ static inline void munlock_vma_page(struct page *page,
 }
 void mlock_new_page(struct page *page);
 bool need_mlock_page_drain(int cpu);
-void mlock_page_drain(int cpu);
+void mlock_page_drain_local(void);
+void mlock_page_drain_remote(int cpu);
 
 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 
@@ -539,7 +540,8 @@ static inline void munlock_vma_page(struct page *page,
 			struct vm_area_struct *vma, bool compound) { }
 static inline void mlock_new_page(struct page *page) { }
 static inline bool need_mlock_page_drain(int cpu) { return false; }
-static inline void mlock_page_drain(int cpu) { }
+static inline void mlock_page_drain_local(void) { }
+static inline void mlock_page_drain_remote(int cpu) { }
 static inline void vunmap_range_noflush(unsigned long start, unsigned long end)
 {
 }

mm/kfence/core.c

@@ -566,6 +566,8 @@ static unsigned long kfence_init_pool(void)
 	 * enters __slab_free() slow-path.
 	 */
 	for (i = 0; i < KFENCE_POOL_SIZE / PAGE_SIZE; i++) {
+		struct slab *slab = page_slab(&pages[i]);
+
 		if (!i || (i % 2))
 			continue;
 
@@ -573,7 +575,11 @@ static unsigned long kfence_init_pool(void)
 		if (WARN_ON(compound_head(&pages[i]) != &pages[i]))
 			return addr;
 
-		__SetPageSlab(&pages[i]);
+		__folio_set_slab(slab_folio(slab));
+#ifdef CONFIG_MEMCG
+		slab->memcg_data = (unsigned long)&kfence_metadata[i / 2 - 1].objcg |
+				   MEMCG_DATA_OBJCGS;
+#endif
 	}
 
 	/*
@@ -1033,6 +1039,9 @@ void __kfence_free(void *addr)
 {
 	struct kfence_metadata *meta = addr_to_metadata((unsigned long)addr);
 
+#ifdef CONFIG_MEMCG
+	KFENCE_WARN_ON(meta->objcg);
+#endif
 	/*
 	 * If the objects of the cache are SLAB_TYPESAFE_BY_RCU, defer freeing
 	 * the object, as the object page may be recycled for other-typed

mm/kfence/kfence.h

@@ -89,6 +89,9 @@ struct kfence_metadata {
 	struct kfence_track free_track;
 	/* For updating alloc_covered on frees. */
 	u32 alloc_stack_hash;
+#ifdef CONFIG_MEMCG
+	struct obj_cgroup *objcg;
+#endif
 };
 
 extern struct kfence_metadata kfence_metadata[CONFIG_KFENCE_NUM_OBJECTS];

mm/kmemleak.c

@@ -796,6 +796,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
 	unsigned long flags;
 	struct kmemleak_object *object;
 	struct kmemleak_scan_area *area = NULL;
+	unsigned long untagged_ptr;
+	unsigned long untagged_objp;
 
 	object = find_and_get_object(ptr, 1);
 	if (!object) {
@@ -804,6 +806,9 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
 		return;
 	}
 
+	untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
+	untagged_objp = (unsigned long)kasan_reset_tag((void *)object->pointer);
+
 	if (scan_area_cache)
 		area = kmem_cache_alloc(scan_area_cache, gfp_kmemleak_mask(gfp));
 
@@ -815,8 +820,8 @@ static void add_scan_area(unsigned long ptr, size_t size, gfp_t gfp)
 		goto out_unlock;
 	}
 	if (size == SIZE_MAX) {
-		size = object->pointer + object->size - ptr;
-	} else if (ptr + size > object->pointer + object->size) {
+		size = untagged_objp + object->size - untagged_ptr;
+	} else if (untagged_ptr + size > untagged_objp + object->size) {
 		kmemleak_warn("Scan area larger than object 0x%08lx\n", ptr);
 		dump_object_info(object);
 		kmem_cache_free(scan_area_cache, area);

mm/madvise.c

@@ -1464,16 +1464,9 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
 
 	while (iov_iter_count(&iter)) {
 		iovec = iov_iter_iovec(&iter);
-		/*
-		 * do_madvise returns ENOMEM if unmapped holes are present
-		 * in the passed VMA. process_madvise() is expected to skip
-		 * unmapped holes passed to it in the 'struct iovec' list
-		 * and not fail because of them. Thus treat -ENOMEM return
-		 * from do_madvise as valid and continue processing.
-		 */
 		ret = do_madvise(mm, (unsigned long)iovec.iov_base,
 					iovec.iov_len, behavior);
-		if (ret < 0 && ret != -ENOMEM)
+		if (ret < 0)
 			break;
 		iov_iter_advance(&iter, iovec.iov_len);
 	}

mm/memory.c

@@ -3918,14 +3918,18 @@ static vm_fault_t __do_fault(struct vm_fault *vmf)
 		return ret;
 
 	if (unlikely(PageHWPoison(vmf->page))) {
+		struct page *page = vmf->page;
 		vm_fault_t poisonret = VM_FAULT_HWPOISON;
 		if (ret & VM_FAULT_LOCKED) {
+			if (page_mapped(page))
+				unmap_mapping_pages(page_mapping(page),
+						    page->index, 1, false);
 			/* Retry if a clean page was removed from the cache. */
-			if (invalidate_inode_page(vmf->page))
-				poisonret = 0;
-			unlock_page(vmf->page);
+			if (invalidate_inode_page(page))
+				poisonret = VM_FAULT_NOPAGE;
+			unlock_page(page);
 		}
-		put_page(vmf->page);
+		put_page(page);
 		vmf->page = NULL;
 		return poisonret;
 	}

mm/migrate.c

@@ -246,7 +246,7 @@ static bool remove_migration_pte(struct folio *folio,
 			set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);
 		}
 		if (vma->vm_flags & VM_LOCKED)
-			mlock_page_drain(smp_processor_id());
+			mlock_page_drain_local();
 
 		trace_remove_migration_pte(pvmw.address, pte_val(pte),
 					   compound_order(new));

mm/mlock.c

@@ -28,7 +28,14 @@
 
 #include "internal.h"
 
-static DEFINE_PER_CPU(struct pagevec, mlock_pvec);
+struct mlock_pvec {
+	local_lock_t lock;
+	struct pagevec vec;
+};
+
+static DEFINE_PER_CPU(struct mlock_pvec, mlock_pvec) = {
+	.lock = INIT_LOCAL_LOCK(lock),
+};
 
 bool can_do_mlock(void)
 {
@@ -203,18 +210,30 @@ static void mlock_pagevec(struct pagevec *pvec)
 	pagevec_reinit(pvec);
 }
 
-void mlock_page_drain(int cpu)
+void mlock_page_drain_local(void)
+{
+	struct pagevec *pvec;
+
+	local_lock(&mlock_pvec.lock);
+	pvec = this_cpu_ptr(&mlock_pvec.vec);
+	if (pagevec_count(pvec))
+		mlock_pagevec(pvec);
+	local_unlock(&mlock_pvec.lock);
+}
+
+void mlock_page_drain_remote(int cpu)
 {
 	struct pagevec *pvec;
 
-	pvec = &per_cpu(mlock_pvec, cpu);
+	WARN_ON_ONCE(cpu_online(cpu));
+	pvec = &per_cpu(mlock_pvec.vec, cpu);
 	if (pagevec_count(pvec))
 		mlock_pagevec(pvec);
 }
 
 bool need_mlock_page_drain(int cpu)
 {
-	return pagevec_count(&per_cpu(mlock_pvec, cpu));
+	return pagevec_count(&per_cpu(mlock_pvec.vec, cpu));
 }
 
 /**
@@ -223,7 +242,10 @@ bool need_mlock_page_drain(int cpu)
  */
 void mlock_folio(struct folio *folio)
 {
-	struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+	struct pagevec *pvec;
+
+	local_lock(&mlock_pvec.lock);
+	pvec = this_cpu_ptr(&mlock_pvec.vec);
 
 	if (!folio_test_set_mlocked(folio)) {
 		int nr_pages = folio_nr_pages(folio);
@@ -236,7 +258,7 @@ void mlock_folio(struct folio *folio)
 	if (!pagevec_add(pvec, mlock_lru(&folio->page)) ||
 	    folio_test_large(folio) || lru_cache_disabled())
 		mlock_pagevec(pvec);
-	put_cpu_var(mlock_pvec);
+	local_unlock(&mlock_pvec.lock);
 }
 
 /**
@@ -245,9 +267,11 @@ void mlock_folio(struct folio *folio)
  */
 void mlock_new_page(struct page *page)
 {
-	struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+	struct pagevec *pvec;
 	int nr_pages = thp_nr_pages(page);
 
+	local_lock(&mlock_pvec.lock);
+	pvec = this_cpu_ptr(&mlock_pvec.vec);
 	SetPageMlocked(page);
 	mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages);
 	__count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
@@ -256,7 +280,7 @@ void mlock_new_page(struct page *page)
 	if (!pagevec_add(pvec, mlock_new(page)) ||
 	    PageHead(page) || lru_cache_disabled())
 		mlock_pagevec(pvec);
-	put_cpu_var(mlock_pvec);
+	local_unlock(&mlock_pvec.lock);
 }
 
 /**
@@ -265,8 +289,10 @@ void mlock_new_page(struct page *page)
  */
 void munlock_page(struct page *page)
 {
-	struct pagevec *pvec = &get_cpu_var(mlock_pvec);
+	struct pagevec *pvec;
 
+	local_lock(&mlock_pvec.lock);
+	pvec = this_cpu_ptr(&mlock_pvec.vec);
 	/*
 	 * TestClearPageMlocked(page) must be left to __munlock_page(),
 	 * which will check whether the page is multiply mlocked.
@@ -276,7 +302,7 @@ void munlock_page(struct page *page)
 	if (!pagevec_add(pvec, page) ||
 	    PageHead(page) || lru_cache_disabled())
 		mlock_pagevec(pvec);
-	put_cpu_var(mlock_pvec);
+	local_unlock(&mlock_pvec.lock);
 }
 
 static int mlock_pte_range(pmd_t *pmd, unsigned long addr,

mm/page_alloc.c

@@ -8367,6 +8367,7 @@ static int page_alloc_cpu_dead(unsigned int cpu)
 	struct zone *zone;
 
 	lru_add_drain_cpu(cpu);
+	mlock_page_drain_remote(cpu);
 	drain_pages(cpu);
 
 	/*

mm/rmap.c

@@ -1683,7 +1683,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
 		 */
 		page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
 		if (vma->vm_flags & VM_LOCKED)
-			mlock_page_drain(smp_processor_id());
+			mlock_page_drain_local();
 		folio_put(folio);
 	}
 
@@ -1961,7 +1961,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
 		 */
 		page_remove_rmap(subpage, vma, folio_test_hugetlb(folio));
 		if (vma->vm_flags & VM_LOCKED)
-			mlock_page_drain(smp_processor_id());
+			mlock_page_drain_local();
 		folio_put(folio);
 	}
 

mm/swap.c

@@ -624,7 +624,6 @@ void lru_add_drain_cpu(int cpu)
 		pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
 
 	activate_page_drain(cpu);
-	mlock_page_drain(cpu);
 }
 
 /**
@@ -706,6 +705,7 @@ void lru_add_drain(void)
 	local_lock(&lru_pvecs.lock);
 	lru_add_drain_cpu(smp_processor_id());
 	local_unlock(&lru_pvecs.lock);
+	mlock_page_drain_local();
 }
 
 /*
@@ -720,6 +720,7 @@ static void lru_add_and_bh_lrus_drain(void)
 	lru_add_drain_cpu(smp_processor_id());
 	local_unlock(&lru_pvecs.lock);
 	invalidate_bh_lrus_cpu();
+	mlock_page_drain_local();
 }
 
 void lru_add_drain_cpu_zone(struct zone *zone)
@@ -728,6 +729,7 @@ void lru_add_drain_cpu_zone(struct zone *zone)
 	lru_add_drain_cpu(smp_processor_id());
 	drain_local_pages(zone);
 	local_unlock(&lru_pvecs.lock);
+	mlock_page_drain_local();
 }
 
 #ifdef CONFIG_SMP

tools/vm/page_owner_sort.c

@@ -441,7 +441,6 @@ static void usage(void)
 		"-n\t\tSort by task command name.\n"
 		"-a\t\tSort by memory allocate time.\n"
 		"-r\t\tSort by memory release time.\n"
-		"-c\t\tCull by comparing stacktrace instead of total block.\n"
 		"-f\t\tFilter out the information of blocks whose memory has been released.\n"
 		"--pid <PID>\tSelect by pid. This selects the information of blocks whose process ID number equals to <PID>.\n"
 		"--tgid <TGID>\tSelect by tgid. This selects the information of blocks whose Thread Group ID number equals to <TGID>.\n"
@@ -466,14 +465,11 @@ int main(int argc, char **argv)
 		{ 0, 0, 0, 0},
 	};
 
-	while ((opt = getopt_long(argc, argv, "acfmnprstP", longopts, NULL)) != -1)
+	while ((opt = getopt_long(argc, argv, "afmnprstP", longopts, NULL)) != -1)
 		switch (opt) {
 		case 'a':
 			cmp = compare_ts;
 			break;
-		case 'c':
-			cull = cull | CULL_STACKTRACE;
-			break;
 		case 'f':
 			filter = filter | FILTER_UNRELEASE;
 			break;