zram_table_entry::flags stores object size in the lower bits and zram
pageflags in the upper bits.  However, for some reason, we use 24 lower
bits, while maximum zram object size is PAGE_SIZE, which requires
PAGE_SHIFT bits (up to 16 on arm64).  This wastes 24 - PAGE_SHIFT bits
that we can use for additional zram pageflags instead.

Also add a BUILD_BUG_ON() to alert us should we run out of bits in
zram_table_entry::flags.

Link: https://lkml.kernel.org/r/20220912152744.527438-1-senozhatsky@chromium.orgSigned-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Brian Geffon <bgeffon@google.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Kdamond is implemented as a periodical split-merge pattern, which will
create and destroy regions possibly at high frequency (hundreds or even
thousands of per sec), depending on the number of regions and aggregation
period.  In that case, kmalloc and kfree could bring speed and space
overheads, which can be improved by using a private kmem cache.

[set_pte_at@outlook.com: creating kmem cache for damon regions by KMEM_CACHE()]
  Link: https://lkml.kernel.org/r/Message-ID:
Link: https://lkml.kernel.org/r/TYCP286MB2323DA1894FA55BB9CF90978CA449@TYCP286MB2323.JPNP286.PROD.OUTLOOK.COMSigned-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

We can use the 'damon_sysfs_kdamond_running()' wrapper directly to check
if the kdamond is running in 'damon_sysfs_turn_damon_on()'.

Link: https://lkml.kernel.org/r/1662995513-24489-1-git-send-email-kaixuxia@tencent.comSigned-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

There's no need to run container_of() as early as we do.

The compiler figures this out, but the resulting code is more readable.

Link: https://lkml.kernel.org/r/20220908081932.77370-1-xhao@linux.alibaba.comSigned-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

A user who reads THP_ZERO_PAGE_ALLOC may be more concerned about the huge
zero pages that are really allocated for thp.  It is misleading to
increase THP_ZERO_PAGE_ALLOC twice if two threads call get_huge_zero_page
concurrently.  Don't increase the value if the huge page is not really
used.

Update Documentation/admin-guide/mm/transhuge.rst to suit.

Link: https://lkml.kernel.org/r/20220909021653.3371879-1-liushixin2@huawei.comSigned-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

It's introduced but never used. Remove it.

Link: https://lkml.kernel.org/r/20220909025711.32012-1-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: zhanglianjie <zhanglianjie@uniontech.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

To handle the discontiguous case, mem_map_next() has a parameter named
`offset`.  As a function caller, one would be confused why "get next
entry" needs a parameter named "offset".  The other drawback of
mem_map_next() is that the callers must take care of the map between
parameter "iter" and "offset", otherwise we may get an hole or duplication
during iteration.  So we use nth_page instead of mem_map_next.

And replace mem_map_offset with nth_page() per Matthew's comments.

Link: https://lkml.kernel.org/r/1662708669-9395-1-git-send-email-lic121@chinatelecom.cnSigned-off-by: Cheng Li <lic121@chinatelecom.cn>
Fixes: 69d177c2 ("hugetlbfs: handle pages higher order than MAX_ORDER")
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

In lru_sort.c and reclaim.c, they are all defining get_monitoring_region()
function, there is no need to define it separately.

As 'get_monitoring_region()' is not a 'static' function anymore, we try to
use a prefix to distinguish with other functions, so there rename it to
'damon_find_biggest_system_ram'.

Link: https://lkml.kernel.org/r/20220909213606.136221-1-sj@kernel.orgSigned-off-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: SeongJae Park <sj@kernel.org>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use DEFINE_SEQ_ATTRIBUTE helper macro to simplify the code.

Link: https://lkml.kernel.org/r/20220909083140.3592919-1-liushixin2@huawei.comSigned-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Marco Elver <elver@google.com>
Tested-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Since commit ffedd09f ("zsmalloc: Stop using slab fields in struct
page") we are using page->page_type (unsigned int) field instead of
page->units (int) as first object offset in a subpage of zspage.  So
get_first_obj_offset() and set_first_obj_offset() functions should work
with unsigned int type.

Link: https://lkml.kernel.org/r/20220909083722.85024-1-avromanov@sberdevices.ru
Fixes: ffedd09f ("zsmalloc: Stop using slab fields in struct page")
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

module_param_call is now completely consistent with module_param_cb, so
there is no need to keep two macros.  Convert module_param_call to
module_param_cb since former is obsolete and latter is more kernel-ish.

Link: https://lkml.kernel.org/r/20220909083947.3595610-1-liushixin2@huawei.comSigned-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Paul Russel <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Commit b1840272 ("Docs/admin-guide/mm/damon/usage: document DAMON
sysfs interface") announced the DAMON debugfs interface deprecation plan,
but it is not so aggressively announced.  As the deprecation time is
coming, this commit makes the announce more easy to be found by adding the
note at the beginning of the DAMON debugfs interface usage document.

Link: https://lkml.kernel.org/r/20220909202901.57977-8-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

'Getting Started' document of DAMON says DAMON user-space tool, damo[1],
is using DAMON debugfs interface, and therefore it needs to ensure debugfs
is mounted.  However, the latest version of the tool is using DAMON sysfs
interface.  Moreover, DAMON debugfs interface is going to be deprecated as
announced by commit b1840272 ("Docs/admin-guide/mm/damon/usage:
document DAMON sysfs interface").

This commit therefore update the document to tell readers about DAMON
sysfs interface dependency instead and never mention about debugfs
interface, which will be deprecated.

[1] https://github.com/awslabs/damo

Link: https://lkml.kernel.org/r/20220909202901.57977-7-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Commit b1840272 ("Docs/admin-guide/mm/damon/usage: document DAMON
sysfs interface") announced the DAMON debugfs interface deprecation plan,
but it is not so aggressively announced.  As the deprecation time is
coming, this commit makes the announce more easy to be found by adding the
note to the config menu of DAMON debugfs interface.

Link: https://lkml.kernel.org/r/20220909202901.57977-6-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The title of the DAMON document for admin-guide, 'Monitoring Data
Accesses', could confuse readers in some ways.  First of all, DAMON is not
the only single way for data access monitoring.  And the document is for
not only the data access monitoring but also data access pattern based
memory management optimizations (DAMOS).  This commit updates the title to
'DAMON: Data Access MONitor', which more explicitly explains what the
document describes.

Link: https://lkml.kernel.org/r/20220909202901.57977-5-sj@kernel.org
Fixes: c4ba6014 ("Documentation: add documents for DAMON")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Preceding commit fixes a bug in 'damon_set_regions()', which allows holes
in the new monitoring target ranges.  This commit adds a kunit test case
for the problem to avoid any regression.

Link: https://lkml.kernel.org/r/20220909202901.57977-4-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

When there are two or more non-contiguous regions intersecting with given
new ranges, 'damon_set_regions()' does not fill the holes.  This commit
makes the function to fill the holes with newly created regions.

[sj@kernel.org: handle error from 'damon_fill_regions_holes()']
  Link: https://lkml.kernel.org/r/20220913215420.57761-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220909202901.57977-3-sj@kernel.org
Fixes: 3f49584b ("mm/damon: implement primitives for the virtual memory address spaces")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Yun Levi <ppbuk5246@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "mm/damon: minor fixes and cleanups".

This patchset contains minor fixes and cleanups for DAMON including

- selftest for a bug we found before (Patch 1), 
- fix of region holes in vaddr corner case and a kunit test for it
  (Patches 2 and 3), and
- documents/Kconfig updates for title wordsmithing (Patch 4) and more
  aggressive DAMON debugfs interface deprecation announcement
  (Patches 5-7).


This patch (of 7):

Commit d26f6070 ("mm/damon/dbgfs: avoid duplicate context directory
creation") fixes a bug which could result in memory leak and DAMON
disablement.  This commit adds a selftest for verifying the fix and avoid
regression.

Link: https://lkml.kernel.org/r/20220909202901.57977-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20220909202901.57977-2-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Yun Levi <ppbuk5246@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

NFSv4 mandates a change attribute to avoid problems with timestamp
granularity, which Linux implements using the i_version counter. This is
particularly important when the underlying filesystem is fast.

Give tmpfs an i_version counter. Since it doesn't have to be persistent,
we can just turn on SB_I_VERSION and sprinkle some inode_inc_iversion
calls in the right places.

Also, while there is no formal spec for xattrs, most implementations
update the ctime on setxattr. Fix shmem_xattr_handler_set to update the
ctime and bump the i_version appropriately.

Link: https://lkml.kernel.org/r/20220909130031.15477-1-jlayton@kernel.orgSigned-off-by: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The switch case 'DAMOS_STAT' and switch case 'default' have same return
value in damon_va_apply_scheme(), and the 'default' case is for DAMOS
actions that not supported by 'vaddr'.  It might make sense to add a
comment here.

[akpm@linux-foundation.org: fx comment grammar]
Link: https://lkml.kernel.org/r/1662606797-23534-1-git-send-email-kaixuxia@tencent.comSigned-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

damon_new_scheme() has too many parameters, so introduce struct
damos_access_pattern to simplify it.

In additon, we can't use a bpf trace kprobe that has more than 5
parameters.

Link: https://lkml.kernel.org/r/20220908191443.129534-1-sj@kernel.orgSigned-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Use PAGE_ALIGNED() helper instead of open-coding operation, no functional
changes here.

Link: https://lkml.kernel.org/r/20220906075312.166595-1-xiujianfeng@huawei.comSigned-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add missing __init/__exit annotations to module init/exit funcs.

Link: https://lkml.kernel.org/r/20220906093530.243262-1-xiujianfeng@huawei.comSigned-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

The struct memcg_vmstats and struct memcg_vmstats_percpu contains two
arrays each for events of size NR_VM_EVENT_ITEMS which can be as large as
110.  However the memcg v1 only uses 4 of those while memcg v2 uses 15. 
The union of both is 17.  On a 64 bit system, we are wasting approximately
((110 - 17) * 8 * 2) * (nr_cpus + 1) bytes which is significant on large
machines.

This patch reduces the size of the given structures by adding one
indirection and only stores array of events which are actually used by the
memcg code.  With this patch, the size of memcg_vmstats has reduced from
2544 bytes to 1056 bytes while the size of memcg_vmstats_percpu has
reduced from 2568 bytes to 1080 bytes.

[akpm@linux-foundation.org: fix memcg_events_local() array index, per Shakeel]
  Link: https://lkml.kernel.org/r/CALvZod70Mvxr+Nzb6k0yiU2RFYjTD=0NFhKK-Eyp+5ejd1PSFw@mail.gmail.com
Link: https://lkml.kernel.org/r/20220907043537.3457014-4-shakeelb@google.comSigned-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This is a preparatory patch for easing the review of the follow up patch
which will reduce the memory overhead of memory cgroups.

Link: https://lkml.kernel.org/r/20220907043537.3457014-3-shakeelb@google.comSigned-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Patch series "memcg: reduce memory overhead of memory cgroups".

Currently a lot of memory is wasted to maintain the vmevents for memory
cgroups as we have multiple arrays of size NR_VM_EVENT_ITEMS which can be
as large as 110.  However memcg code uses small portion of those entries. 
This patch series eliminate this overhead by removing the unneeded vmevent
entries from memory cgroup data structures.


This patch (of 3):

This is a preparatory patch to reduce the memory overhead of memory
cgroup. The struct memcg_vmstats is the largest object embedded into the
struct mem_cgroup. This patch extracts struct memcg_vmstats from struct
mem_cgroup to ease the following patches in reducing the size of struct
memcg_vmstats.

Link: https://lkml.kernel.org/r/20220907043537.3457014-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20220907043537.3457014-2-shakeelb@google.comSigned-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add new pageblock_start_pfn() and pageblock_align() macro which are needed
by memblock tests.

Link: https://lkml.kernel.org/r/20220907082643.186979-1-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add pageblock_aligned() and use it to simplify code.

Link: https://lkml.kernel.org/r/20220907060844.126891-3-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add pageblock_align() macro and use it to simplify code.

Link: https://lkml.kernel.org/r/20220907060844.126891-2-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Move pageblock_start_pfn/pageblock_end_pfn() into pageblock-flags.h, then
they could be used somewhere else, not only in compaction, also use
ALIGN_DOWN() instead of round_down() to be pair with ALIGN(), which should
be same for pageblock usage.

Link: https://lkml.kernel.org/r/20220907060844.126891-1-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Remove an expensive and unnecessary operation as PCP pages are safely
skipped when reading page owner.PCP pages can be skipped because
PAGE_EXT_OWNER_ALLOCATED is cleared.

With draining PCP pages, these pages are moved to buddy list so they can
be identified as buddy pages and skipped quickly.  Although it improved
efficiency of PFN walker, the drain is guaranteed expensive that is
unlikely to be offset by a slight increase in efficiency when skipping
free pages.

PAGE_EXT_OWNER_ALLOCATED is cleared in the page owner reset path below:
	free_unref_page
		-> free_unref_page_prepare
			-> free_pcp_prepare
				-> free_pages_prepare which do page owner
				reset
		-> free_unref_page_commit which add pages into pcp list

Link: https://lkml.kernel.org/r/1662704326-15899-1-git-send-email-quic_zhenhuah@quicinc.com
Link: https://lkml.kernel.org/r/1662633204-10044-1-git-send-email-quic_zhenhuah@quicinc.com
Link: https://lkml.kernel.org/r/1662537673-9392-1-git-send-email-quic_zhenhuah@quicinc.comSigned-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

In damon_sysfs_before_terminate(), it needs to check whether ctx->ops.id
supports 'DAMON_OPS_VADDR' or 'DAMON_OPS_FVADDR', there we can use
damon_target_has_pid() instead.

Link: https://lkml.kernel.org/r/20220907084116.62053-1-xhao@linux.alibaba.comSigned-off-by: Xin Hao <xhao@linux.alibaba.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

We iterate the whole regions list every time to get the first/last regions
intersecting with the specific range in damon_set_regions(), in order to
add new region or resize existing regions to fit in the specific range. 
Actually, it is unnecessary to iterate the new added regions and the front
regions that have been checked.  Just iterate the regions list from the
current point using list_for_each_entry_from() every time to improve
performance.

The kunit tests passed:
 [PASSED] damon_test_apply_three_regions1
 [PASSED] damon_test_apply_three_regions2
 [PASSED] damon_test_apply_three_regions3
 [PASSED] damon_test_apply_three_regions4

Link: https://lkml.kernel.org/r/1662477527-13003-1-git-send-email-kaixuxia@tencent.comSigned-off-by: Kaixu Xia <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

HMM selftests use an in-kernel pseudo device to emulate device memory. 
The pseudo device registers a major device range for two or four pseudo
device instances.  User space has a script that reads /proc/devices in
order to find the assigned major number, and sends that to mknod(1), once
for each node.

Change this to properly use cdev and struct device APIs.

Delete the /proc/devices parsing from the user-space test script, now that
it is unnecessary.

Also, delete an unused field in struct dmirror_device: devmem.

Link: https://lkml.kernel.org/r/20220826050631.25771-1-mpenttil@redhat.comSigned-off-by: Mika Penttilä <mpenttil@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Update the report header for invalid- and double-free bugs to contain the
address being freed:

BUG: KASAN: invalid-free in kfree+0x280/0x2a8
Free of addr ffff00000beac001 by task kunit_try_catch/99

Link: https://lkml.kernel.org/r/fce40f8dbd160972fe01a1ff39d0c426c310e4b7.1662852281.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Move KASAN tests to mm/kasan/ to keep the test code alongside the
implementation.

Link: https://lkml.kernel.org/r/676398f0aeecd47d2f8e3369ea0e95563f641a36.1662416260.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add a new use-after-free test that checks that KASAN detects
use-after-free when another object was allocated in the same slot.

This test is mainly relevant for the tag-based modes, which do not use
quarantine.

Once [1] is resolved, this test can be extended to check that the stack
traces in the report point to the proper kmalloc/kfree calls.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=212203

Link: https://lkml.kernel.org/r/0659cfa15809dd38faa02bc0a59d0b5dbbd81211.1662411800.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Identify the bug type for the tag-based modes based on the stack trace
entries found in the stack ring.

If a free entry is found first (meaning that it was added last), mark the
bug as use-after-free.  If an alloc entry is found first, mark the bug as
slab-out-of-bounds.  Otherwise, assign the common bug type.

This change returns the functionalify of the previously dropped
CONFIG_KASAN_TAGS_IDENTIFY.

Link: https://lkml.kernel.org/r/13ce7fa07d9d995caedd1439dfae4d51401842f2.1662411800.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Instead of using a large static array, allocate the stack ring dynamically
via memblock_alloc().

The size of the stack ring is controlled by a new kasan.stack_ring_size
command-line parameter.  When kasan.stack_ring_size is not provided, the
default value of 32 << 10 is used.

When the stack trace collection is disabled via kasan.stacktrace=off, the
stack ring is not allocated.

Link: https://lkml.kernel.org/r/03b82ab60db53427e9818e0b0c1971baa10c3cbc.1662411800.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add support for the kasan.stacktrace command-line argument for Software
Tag-Based KASAN.

The following patch adds a command-line argument for selecting the stack
ring size, and, as the stack ring is supported by both the Software and
the Hardware Tag-Based KASAN modes, it is natural that both of them have
support for kasan.stacktrace too.

Link: https://lkml.kernel.org/r/3b43059103faa7f8796017847b7d674b658f11b5.1662411799.git.andreyknvl@google.comSigned-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>