- 11 Sep, 2013 40 commits
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Wanpeng Li authored
The return value outside for loop is always zero which means madvise_hwpoison return success, however, this is not truth for soft_offline_page w/ failure return value. Signed-off-by:
Wanpeng Li <liwanp@linux.vnet.ibm.com> Reviewed-by:
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Wanpeng Li authored
Injecting memory failure for page 0x19d0 at 0xb77d2000 MCE 0x19d0: non LRU page recovery: Ignored MCE: Software-unpoisoned page 0x19d0 BUG: Bad page state in process bash pfn:019d0 page:f3461a00 count:0 mapcount:0 mapping: (null) index:0x0 page flags: 0x40000404(referenced|reserved) Modules linked in: nfsd auth_rpcgss i915 nfs_acl nfs lockd video drm_kms_helper drm bnep rfcomm sunrpc bluetooth psmouse parport_pc ppdev lp serio_raw fscache parport gpio_ich lpc_ich mac_hid i2c_algo_bit tpm_tis wmi usb_storage hid_generic usbhid hid e1000e firewire_ohci firewire_core ahci ptp libahci pps_core crc_itu_t CPU: 3 PID: 2123 Comm: bash Not tainted 3.11.0-rc6+ #12 Hardware name: LENOVO 7034DD7/ , BIOS 9HKT47AUS 01//2012 00000000 00000000 e9625ea0 c15ec49b f3461a00 e9625eb8 c15ea119 c17cbf18 ef084314 000019d0 f3461a00 e9625ed8 c110dc8a f3461a00 00000001 00000000 f3461a00 40000404 00000000 e9625ef8 c110dcc1 f3461a00 f3461a00 000019d0 Call Trace: dump_stack+0x41/0x52 bad_page+0xcf/0xeb free_pages_prepare+0x12a/0x140 free_hot_cold_page+0x21/0x110 __put_single_page+0x21/0x30 put_page+0x25/0x40 unpoison_memory+0x107/0x200 hwpoison_unpoison+0x20/0x30 simple_attr_write+0xb6/0xd0 vfs_write+0xa0/0x1b0 SyS_write+0x4f/0x90 sysenter_do_call+0x12/0x22 Disabling lock debugging due to kernel taint Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <errno.h> #define PAGES_TO_TEST 1 #define PAGE_SIZE 4096 int main(void) { char *mem; mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1) return -1; munmap(mem, PAGES_TO_TEST * PAGE_SIZE); return 0; } There is one page reference count for default empty zero page, madvise_hwpoison add another one by get_user_pages_fast. memory_hwpoison reduce one page reference count since it's a non LRU page. unpoison_memory release the last page reference count and free empty zero page to buddy system which is not correct since empty zero page has PG_reserved flag. This patch fix it by don't reduce the page reference count under 1 against empty zero page. Signed-off-by: -
Wanpeng Li authored
Hwpoison injection doesn't implement read method for corrupt-pfn/unpoison-pfn attributes: # cat /sys/kernel/debug/hwpoison/corrupt-pfn cat: /sys/kernel/debug/hwpoison/corrupt-pfn: Permission denied # cat /sys/kernel/debug/hwpoison/unpoison-pfn cat: /sys/kernel/debug/hwpoison/unpoison-pfn: Permission denied This patch changes the permission of corrupt-pfn/unpoison-pfn to 0200. Signed-off-by:
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Wanpeng Li authored
madvise hwpoison inject will poison the read-only empty zero page if there is no write access before poison. Empty zero page reference count will be increased for hwpoison, subsequent poison zero page will return directly since page has already been set PG_hwpoison, however, page reference count is still increased by get_user_pages_fast. The unpoison process will unpoison the empty zero page and decrease the reference count successfully for the fist time, however, subsequent unpoison empty zero page will return directly since page has already been unpoisoned and without decrease the page reference count of empty zero page. This patch fixes it by make madvise_hwpoison() put a page and return immediately (without calling memory_failure() or soft_offline_page()) when the page is already hwpoisoned. Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <errno.h> #define PAGES_TO_TEST 3 #define PAGE_SIZE 4096 int main(void) { char *mem; int i; mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1) return -1; munmap(mem, PAGES_TO_TEST * PAGE_SIZE); return 0; } Add printk to dump page reference count: [ 93.075959] Injecting memory failure for page 0x19d0 at 0xb77d8000 [ 93.076207] MCE 0x19d0: non LRU page recovery: Ignored [ 93.076209] pfn 0x19d0, page count = 1 after memory failure [ 93.076220] Injecting memory failure for page 0x19d0 at 0xb77d9000 [ 93.076221] MCE 0x19d0: already hardware poisoned [ 93.076222] pfn 0x19d0, page count = 2 after memory failure [ 93.076224] Injecting memory failure for page 0x19d0 at 0xb77da000 [ 93.076224] MCE 0x19d0: already hardware poisoned [ 93.076225] pfn 0x19d0, page count = 3 after memory failure Signed-off-by: -
Wanpeng Li authored
Add '#' to madvise_hwpoison. Before patch: [ 95.892866] Injecting memory failure for page 19d0 at b7786000 [ 95.893151] MCE 0x19d0: non LRU page recovery: Ignored After patch: [ 95.892866] Injecting memory failure for page 0x19d0 at 0xb7786000 [ 95.893151] MCE 0x19d0: non LRU page recovery: Ignored Signed-off-by:
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Wanpeng Li authored
Drop forward reference declarations __soft_offline_page. Signed-off-by:
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Wanpeng Li authored
Set pageblock migration type will hold zone->lock which is heavy contended in system to avoid race. However, soft offline page will set pageblock migration type twice during get page if the page is in used, not hugetlbfs page and not on lru list. There is unnecessary to set the pageblock migration type and hold heavy contended zone->lock again if the first round get page have already set the pageblock to right migration type. The trick here is migration type is MIGRATE_ISOLATE. There are other two parts can change MIGRATE_ISOLATE except hwpoison. One is memory hoplug, however, we hold lock_memory_hotplug() which avoid race. The second is CMA which umovable page allocation requst can't fallback to. So it's safe here. Signed-off-by:
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Wanpeng Li authored
Replace atomic_long_sub() with atomic_long_dec() since the page is normal page instead of hugetlbfs page or thp. Signed-off-by:
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Wanpeng Li authored
There is a race between hwpoison page and unpoison page, memory_failure set the page hwpoison and increase num_poisoned_pages without hold page lock, and one page count will be accounted against thp for num_poisoned_pages. However, unpoison can occur before memory_failure hold page lock and split transparent hugepage, unpoison will decrease num_poisoned_pages by 1 << compound_order since memory_failure has not yet split transparent hugepage with page lock held. That means we account one page for hwpoison and 1 << compound_order for unpoison. This patch fix it by inserting a PageTransHuge check before doing TestClearPageHWPoison, unpoison failed without clearing PageHWPoison and decreasing num_poisoned_pages. A B memory_failue TestSetPageHWPoison(p); if (PageHuge(p)) nr_pages = 1 << compound_order(hpage); else nr_pages = 1; atomic_long_add(nr_pages, &num_poisoned_pages); unpoison_memory nr_pages = 1<< compound_trans_order(page); if(TestClearPageHWPoison(p)) atomic_long_sub(nr_pages, &num_poisoned_pages); lock page if (!PageHWPoison(p)) unlock page and return hwpoison_user_mappings if (PageTransHuge(hpage)) split_huge_page(hpage); Signed-off-by: -
Wanpeng Li authored
compound lock is introduced by commit e9da73d6("thp: compound_lock."), it is used to serialize put_page against __split_huge_page_refcount(). In addition, transparent hugepages will be splitted in hwpoison handler and just one subpage will be poisoned. There is unnecessary to hold compound lock for hugetlbfs page. This patch replace compound_trans_order by compond_order in the place where the page is hugetlbfs page. Signed-off-by:
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Wanpeng Li authored
memory_failure() store the page flag of the error page before doing unmap, and (only) if the first check with page flags at the time decided the error page is unknown, it do the second check with the stored page flag since memory_failure() does unmapping of the error pages before doing page_action(). This unmapping changes the page state, especially page_remove_rmap() (called from try_to_unmap_one()) clears PG_mlocked, so page_action() can't catch mlocked pages after that. However, memory_failure() can't handle memory errors on dirty mlocked pages correctly. try_to_unmap_one will move the dirty bit from pte to the physical page, the second check lose it since it check the stored page flag. This patch fix it by restore PG_dirty flag to stored page flag if the page is dirty. Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <sys/types.h> #include <errno.h> #define PAGES_TO_TEST 2 #define PAGE_SIZE 4096 int main(void) { char *mem; int i; mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_LOCKED, 0, 0); for (i = 0; i < PAGES_TO_TEST; i++) mem[i * PAGE_SIZE] = 'a'; if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1) return -1; return 0; } Before patch: [ 912.839247] Injecting memory failure for page 7dfb8 at 7f6b4e37b000 [ 912.839257] MCE 0x7dfb8: clean mlocked LRU page recovery: Recovered [ 912.845550] MCE 0x7dfb8: clean mlocked LRU page still referenced by 1 users [ 912.852586] Injecting memory failure for page 7e6aa at 7f6b4e37c000 [ 912.852594] MCE 0x7e6aa: clean mlocked LRU page recovery: Recovered [ 912.858936] MCE 0x7e6aa: clean mlocked LRU page still referenced by 1 users After patch: [ 163.590225] Injecting memory failure for page 91bc2f at 7f9f5b0e5000 [ 163.590264] MCE 0x91bc2f: dirty mlocked LRU page recovery: Recovered [ 163.596680] MCE 0x91bc2f: dirty mlocked LRU page still referenced by 1 users [ 163.603831] Injecting memory failure for page 91cdd3 at 7f9f5b0e6000 [ 163.603852] MCE 0x91cdd3: dirty mlocked LRU page recovery: Recovered [ 163.610305] MCE 0x91cdd3: dirty mlocked LRU page still referenced by 1 users Signed-off-by: -
Naoya Horiguchi authored
Soft offline code expects that MIGRATE_ISOLATE is set on the target page only during soft offlining work. But currenly it doesn't work as expected when get_any_page() fails and returns negative value. In the result, end users can have unexpectedly isolated pages. This patch just fixes it. Signed-off-by:
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Wang Sheng-Hui authored
Set _mapcount PAGE_BUDDY_MAPCOUNT_VALUE to make the page buddy. Not the magic number -2. Signed-off-by:
Wang Sheng-Hui <shhuiw@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Cyrill Gorcunov authored
_PAGE_SOFT_DIRTY bit should never be set on present pte so add VM_BUG_ON to catch any potential future abuse. Also add a comment on _PAGE_SWP_SOFT_DIRTY definition explaining scope of its usage. Signed-off-by:
Cyrill Gorcunov <gorcunov@openvz.org> Acked-by:
Pavel Emelyanov <xemul@parallels.com> Acked-by:
Jan Beulich <jbeulich@suse.com> Signed-off-by:
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Maxim Patlasov authored
The feature prevents mistrusted filesystems (ie: FUSE mounts created by unprivileged users) to grow a large number of dirty pages before throttling. For such filesystems balance_dirty_pages always check bdi counters against bdi limits. I.e. even if global "nr_dirty" is under "freerun", it's not allowed to skip bdi checks. The only use case for now is fuse: it sets bdi max_ratio to 1% by default and system administrators are supposed to expect that this limit won't be exceeded. The feature is on if a BDI is marked by BDI_CAP_STRICTLIMIT flag. A filesystem may set the flag when it initializes its BDI. The problematic scenario comes from the fact that nobody pays attention to the NR_WRITEBACK_TEMP counter (i.e. number of pages under fuse writeback). The implementation of fuse writeback releases original page (by calling end_page_writeback) almost immediately. A fuse request queued for real processing bears a copy of original page. Hence, if userspace fuse daemon doesn't finalize write requests in timely manner, an aggressive mmap writer can pollute virtually all memory by those temporary fuse page copies. They are carefully accounted in NR_WRITEBACK_TEMP, but nobody cares. To make further explanations shorter, let me use "NR_WRITEBACK_TEMP problem" as a shortcut for "a possibility of uncontrolled grow of amount of RAM consumed by temporary pages allocated by kernel fuse to process writeback". The problem was very easy to reproduce. There is a trivial example filesystem implementation in fuse userspace distribution: fusexmp_fh.c. I added "sleep(1);" to the write methods, then recompiled and mounted it. Then created a huge file on the mount point and run a simple program which mmap-ed the file to a memory region, then wrote a data to the region. An hour later I observed almost all RAM consumed by fuse writeback. Since then some unrelated changes in kernel fuse made it more difficult to reproduce, but it is still possible now. Putting this theoretical happens-in-the-lab thing aside, there is another thing that really hurts real world (FUSE) users. This is write-through page cache policy FUSE currently uses. I.e. handling write(2), kernel fuse populates page cache and flushes user data to the server synchronously. This is excessively suboptimal. Pavel Emelyanov's patches ("writeback cache policy") solve the problem, but they also make resolving NR_WRITEBACK_TEMP problem absolutely necessary. Otherwise, simply copying a huge file to a fuse mount would result in memory starvation. Miklos, the maintainer of FUSE, believes strictlimit feature the way to go. And eventually putting FUSE topics aside, there is one more use-case for strictlimit feature. Using a slow USB stick (mass storage) in a machine with huge amount of RAM installed is a well-known pain. Let's make simple computations. Assuming 64GB of RAM installed, existing implementation of balance_dirty_pages will start throttling only after 9.6GB of RAM becomes dirty (freerun == 15% of total RAM). So, the command "cp 9GB_file /media/my-usb-storage/" may return in a few seconds, but subsequent "umount /media/my-usb-storage/" will take more than two hours if effective throughput of the storage is, to say, 1MB/sec. After inclusion of strictlimit feature, it will be trivial to add a knob (e.g. /sys/devices/virtual/bdi/x:y/strictlimit) to enable it on demand. Manually or via udev rule. May be I'm wrong, but it seems to be quite a natural desire to limit the amount of dirty memory for some devices we are not fully trust (in the sense of sustainable throughput). [akpm@linux-foundation.org: fix warning in page-writeback.c] Signed-off-by:Maxim Patlasov <MPatlasov@parallels.com> Cc: Jan Kara <jack@suse.cz> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Pavel Emelyanov <xemul@parallels.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by:
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Chen Gang authored
'*lenp' may be less than "sizeof(kbuf)" so we must check this before the next copy_to_user(). pdflush_proc_obsolete() is called by sysctl which 'procname' is "nr_pdflush_threads", if the user passes buffer length less than "sizeof(kbuf)", it will cause issue. Signed-off-by:
Chen Gang <gang.chen@asianux.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Jeff Moyer <jmoyer@redhat.com> Signed-off-by:
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Chen Gang authored
In alloc_new_pmd(), if pud_alloc() was called successfully, but pmd_alloc() fails, avoid leaking `pud'. Signed-off-by:
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Wanpeng Li authored
Use wrapper function get_vm_area_size to calculate size of vm area. Signed-off-by:
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Wanpeng Li authored
It's not used globally and could be static. Signed-off-by:
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Wanpeng Li authored
After commit 9bdac914 ("sparsemem: Put mem map for one node together."), vmemmap for one node will be allocated together, its logic is similar as memory allocation for pageblock flags. This patch introduces alloc_usemap_and_memmap to extract the same logic of memory alloction for pageblock flags and vmemmap. Signed-off-by:
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Lisa Du authored
This patch is based on KOSAKI's work and I add a little more description, please refer https://lkml.org/lkml/2012/6/14/74. Currently, I found system can enter a state that there are lots of free pages in a zone but only order-0 and order-1 pages which means the zone is heavily fragmented, then high order allocation could make direct reclaim path's long stall(ex, 60 seconds) especially in no swap and no compaciton enviroment. This problem happened on v3.4, but it seems issue still lives in current tree, the reason is do_try_to_free_pages enter live lock: kswapd will go to sleep if the zones have been fully scanned and are still not balanced. As kswapd thinks there's little point trying all over again to avoid infinite loop. Instead it changes order from high-order to 0-order because kswapd think order-0 is the most important. Look at 73ce02e9 in detail. If watermarks are ok, kswapd will go back to sleep and may leave zone->all_unreclaimable =3D 0. It assume high-order users can still perform direct reclaim if they wish. Direct reclaim continue to reclaim for a high order which is not a COSTLY_ORDER without oom-killer until kswapd turn on zone->all_unreclaimble= . This is because to avoid too early oom-kill. So it means direct_reclaim depends on kswapd to break this loop. In worst case, direct-reclaim may continue to page reclaim forever when kswapd sleeps forever until someone like watchdog detect and finally kill the process. As described in: http://thread.gmane.org/gmane.linux.kernel.mm/103737 We can't turn on zone->all_unreclaimable from direct reclaim path because direct reclaim path don't take any lock and this way is racy. Thus this patch removes zone->all_unreclaimable field completely and recalculates zone reclaimable state every time. Note: we can't take the idea that direct-reclaim see zone->pages_scanned directly and kswapd continue to use zone->all_unreclaimable. Because, it is racy. commit 929bea7c (vmscan: all_unreclaimable() use zone->all_unreclaimable as a name) describes the detail. [akpm@linux-foundation.org: uninline zone_reclaimable_pages() and zone_reclaimable()] Cc: Aaditya Kumar <aaditya.kumar.30@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Nick Piggin <npiggin@gmail.com> Acked-by:
Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Cc: Bob Liu <lliubbo@gmail.com> Cc: Neil Zhang <zhangwm@marvell.com> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Reviewed-by:
Michal Hocko <mhocko@suse.cz> Acked-by:
Minchan Kim <minchan@kernel.org> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
Lisa Du <cldu@marvell.com> Signed-off-by:
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Vlastimil Babka authored
Currently munlock_vma_pages_range() calls follow_page_mask() to obtain each individual struct page. This entails repeated full page table translations and page table lock taken for each page separately. This patch avoids the costly follow_page_mask() where possible, by iterating over ptes within single pmd under single page table lock. The first pte is obtained by get_locked_pte() for non-THP page acquired by the initial follow_page_mask(). The rest of the on-stack pagevec for munlock is filled up using pte_walk as long as pte_present() and vm_normal_page() are sufficient to obtain the struct page. After this patch, a 14% speedup was measured for munlocking a 56GB large memory area with THP disabled. Signed-off-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Jörn Engel <joern@logfs.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Vlastimil Babka authored
The performance of the fast path in munlock_vma_range() can be further improved by avoiding atomic ops of a redundant get_page()/put_page() pair. When calling get_page() during page isolation, we already have the pin from follow_page_mask(). This pin will be then returned by __pagevec_lru_add(), after which we do not reference the pages anymore. After this patch, an 8% speedup was measured for munlocking a 56GB large memory area with THP disabled. Signed-off-by:
Jörn Engel <joern@logfs.org> Acked-by:
Mel Gorman <mgorman@suse.de> Cc: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by:
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Vlastimil Babka authored
After introducing batching by pagevecs into munlock_vma_range(), we can further improve performance by bypassing the copying into per-cpu pagevec and the get_page/put_page pair associated with that. Instead we perform LRU putback directly from our pagevec. However, this is possible only for single-mapped pages that are evictable after munlock. Unevictable pages require rechecking after putting on the unevictable list, so for those we fallback to putback_lru_page(), hich handles that. After this patch, a 13% speedup was measured for munlocking a 56GB large memory area with THP disabled. [akpm@linux-foundation.org:clarify comment] Signed-off-by:
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Vlastimil Babka authored
Depending on previous batch which introduced batched isolation in munlock_vma_range(), we can batch also the updates of NR_MLOCK page stats. After the whole pagevec is processed for page isolation, the stats are updated only once with the number of successful isolations. There were however no measurable perfomance gains. Signed-off-by:
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Vlastimil Babka authored
Currently, munlock_vma_range() calls munlock_vma_page on each page in a loop, which results in repeated taking and releasing of the lru_lock spinlock for isolating pages one by one. This patch batches the munlock operations using an on-stack pagevec, so that isolation is done under single lru_lock. For THP pages, the old behavior is preserved as they might be split while putting them into the pagevec. After this patch, a 9% speedup was measured for munlocking a 56GB large memory area with THP disabled. A new function __munlock_pagevec() is introduced that takes a pagevec and: 1) It clears PageMlocked and isolates all pages under lru_lock. Zone page stats can be also updated using the variant which assumes disabled interrupts. 2) It finishes the munlock and lru putback on all pages under their lock_page. Note that previously, lock_page covered also the PageMlocked clearing and page isolation, but it is not needed for those operations. Signed-off-by:
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Vlastimil Babka authored
In munlock_vma_range(), lru_add_drain() is currently called in a loop before each munlock_vma_page() call. This is suboptimal for performance when munlocking many pages. The benefits of per-cpu pagevec for batching the LRU putback are removed since the pagevec only holds at most one page from the previous loop's iteration. The lru_add_drain() call also does not serve any purposes for correctness - it does not even drain pagavecs of all cpu's. The munlock code already expects and handles situations where a page cannot be isolated from the LRU (e.g. because it is on some per-cpu pagevec). The history of the (not commented) call also suggest that it appears there as an oversight rather than intentionally. Before commit ff6a6da6 ("mm: accelerate munlock() treatment of THP pages") the call happened only once upon entering the function. The commit has moved the call into the while loope. So while the other changes in the commit improved munlock performance for THP pages, it introduced the abovementioned suboptimal per-cpu pagevec usage. Further in history, before commit 408e82b7 ("mm: munlock use follow_page"), munlock_vma_pages_range() was just a wrapper around __mlock_vma_pages_range which performed both mlock and munlock depending on a flag. However, before ba470de4 ("mmap: handle mlocked pages during map, remap, unmap") the function handled only mlock, not munlock. The lru_add_drain call thus comes from the implementation in commit b291f000 ("mlock: mlocked pages are unevictable" and was intended only for mlocking, not munlocking. The original intention of draining the LRU pagevec at mlock time was to ensure the pages were on the LRU before the lock operation so that they could be placed on the unevictable list immediately. There is very little motivation to do the same in the munlock path this, particularly for every single page. This patch therefore removes the call completely. After removing the call, a 10% speedup was measured for munlock() of a 56GB large memory area with THP disabled. Signed-off-by:
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Vlastimil Babka authored
The goal of this patch series is to improve performance of munlock() of large mlocked memory areas on systems without THP. This is motivated by reported very long times of crash recovery of processes with such areas, where munlock() can take several seconds. See http://lwn.net/Articles/548108/ The work was driven by a simple benchmark (to be included in mmtests) that mmaps() e.g. 56GB with MAP_LOCKED | MAP_POPULATE and measures the time of munlock(). Profiling was performed by attaching operf --pid to the process and sending a signal to trigger the munlock() part and then notify bach the monitoring wrapper to stop operf, so that only munlock() appears in the profile. The profiles have shown that CPU time is spent mostly by atomic operations and repeated locking per single pages. This series aims to reduce both, starting from simpler to more complex changes. Patch 1 performs a simple cleanup in putback_lru_page() so that page lru base type is not determined without being actually needed. Patch 2 removes an unnecessary call to lru_add_drain() which drains the per-cpu pagevec after each munlocked page is put there. Patch 3 changes munlock_vma_range() to use an on-stack pagevec for isolating multiple non-THP pages under a single lru_lock instead of locking and processing each page separately. Patch 4 changes the NR_MLOCK accounting to be called only once per the pvec introduced by previous patch. Patch 5 uses the introduced pagevec to batch also the work of putback_lru_page when possible, bypassing the per-cpu pvec and associated overhead. Patch 6 removes a redundant get_page/put_page pair which saves costly atomic operations. Patch 7 avoids calling follow_page_mask() on each individual page, and obtains multiple page references under a single page table lock where possible. Measurements were made using 3.11-rc3 as a baseline. The first set of measurements shows the possibly ideal conditions where batching should help the most. All memory is allocated from a single NUMA node and THP is disabled. timedmunlock 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 0 1 2 3 4 5 6 7 Elapsed min 3.38 ( 0.00%) 3.39 ( -0.13%) 3.00 ( 11.33%) 2.70 ( 20.20%) 2.67 ( 21.11%) 2.37 ( 29.88%) 2.20 ( 34.91%) 1.91 ( 43.59%) Elapsed mean 3.39 ( 0.00%) 3.40 ( -0.23%) 3.01 ( 11.33%) 2.70 ( 20.26%) 2.67 ( 21.21%) 2.38 ( 29.88%) 2.21 ( 34.93%) 1.92 ( 43.46%) Elapsed stddev 0.01 ( 0.00%) 0.01 (-43.09%) 0.01 ( 15.42%) 0.01 ( 23.42%) 0.00 ( 89.78%) 0.01 ( -7.15%) 0.00 ( 76.69%) 0.02 (-91.77%) Elapsed max 3.41 ( 0.00%) 3.43 ( -0.52%) 3.03 ( 11.29%) 2.72 ( 20.16%) 2.67 ( 21.63%) 2.40 ( 29.50%) 2.21 ( 35.21%) 1.96 ( 42.39%) Elapsed range 0.03 ( 0.00%) 0.04 (-51.16%) 0.02 ( 6.27%) 0.02 ( 14.67%) 0.00 ( 88.90%) 0.03 (-19.18%) 0.01 ( 73.70%) 0.06 (-113.35% The second set of measurements simulates the worst possible conditions for batching by using numactl --interleave, so that there is in fact only one page per pagevec. Even in this case the series seems to improve performance thanks to reduced atomic operations and removal of lru_add_drain(). timedmunlock 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 0 1 2 3 4 5 6 7 Elapsed min 4.00 ( 0.00%) 4.04 ( -0.93%) 3.87 ( 3.37%) 3.72 ( 6.94%) 3.81 ( 4.72%) 3.69 ( 7.82%) 3.64 ( 8.92%) 3.41 ( 14.81%) Elapsed mean 4.17 ( 0.00%) 4.15 ( 0.51%) 4.03 ( 3.49%) 3.89 ( 6.84%) 3.86 ( 7.48%) 3.89 ( 6.69%) 3.70 ( 11.27%) 3.48 ( 16.59%) Elapsed stddev 0.16 ( 0.00%) 0.08 ( 50.76%) 0.10 ( 41.58%) 0.16 ( 4.59%) 0.05 ( 72.38%) 0.19 (-12.91%) 0.05 ( 68.09%) 0.06 ( 66.03%) Elapsed max 4.34 ( 0.00%) 4.32 ( 0.56%) 4.19 ( 3.62%) 4.12 ( 5.15%) 3.91 ( 9.88%) 4.12 ( 5.25%) 3.80 ( 12.58%) 3.56 ( 18.08%) Elapsed range 0.34 ( 0.00%) 0.28 ( 17.91%) 0.32 ( 6.45%) 0.40 (-15.73%) 0.10 ( 70.06%) 0.43 (-24.84%) 0.15 ( 55.32%) 0.15 ( 56.16%) For completeness, a third set of measurements shows the situation where THP is enabled and allocations are again done on a single NUMA node. Here munlock() is already very fast thanks to huge pages, and this series does not compromise that performance. It seems that the removal of call to lru_add_drain() still helps a bit. timedmunlock 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 0 1 2 3 4 5 6 7 Elapsed min 0.01 ( 0.00%) 0.01 ( -0.11%) 0.01 ( 6.59%) 0.01 ( 5.41%) 0.01 ( 5.45%) 0.01 ( 5.03%) 0.01 ( 6.08%) 0.01 ( 5.20%) Elapsed mean 0.01 ( 0.00%) 0.01 ( -0.27%) 0.01 ( 6.39%) 0.01 ( 5.30%) 0.01 ( 5.32%) 0.01 ( 5.03%) 0.01 ( 5.97%) 0.01 ( 5.22%) Elapsed stddev 0.00 ( 0.00%) 0.00 ( -9.59%) 0.00 ( 10.77%) 0.00 ( 3.24%) 0.00 ( 24.42%) 0.00 ( 31.86%) 0.00 ( -7.46%) 0.00 ( 6.11%) Elapsed max 0.01 ( 0.00%) 0.01 ( -0.01%) 0.01 ( 6.83%) 0.01 ( 5.42%) 0.01 ( 5.79%) 0.01 ( 5.53%) 0.01 ( 6.08%) 0.01 ( 5.26%) Elapsed range 0.00 ( 0.00%) 0.00 ( 7.30%) 0.00 ( 24.38%) 0.00 ( 6.10%) 0.00 ( 30.79%) 0.00 ( 42.52%) 0.00 ( 6.11%) 0.00 ( 10.07%) This patch (of 7): In putback_lru_page() since commit c53954a0 (""mm: remove lru parameter from __lru_cache_add and lru_cache_add_lru") it is no longer needed to determine lru list via page_lru_base_type(). This patch replaces it with simple flag is_unevictable which says that the page was put on the inevictable list. This is the only information that matters in subsequent tests. Signed-off-by:
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Cyrill Gorcunov authored
Pavel reported that in case if vma area get unmapped and then mapped (or expanded) in-place, the soft dirty tracker won't be able to recognize this situation since it works on pte level and ptes are get zapped on unmap, loosing soft dirty bit of course. So to resolve this situation we need to track actions on vma level, there VM_SOFTDIRTY flag comes in. When new vma area created (or old expanded) we set this bit, and keep it here until application calls for clearing soft dirty bit. Thus when user space application track memory changes now it can detect if vma area is renewed. Reported-by:
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SeungHun Lee authored
cpuset_zone_allowed is changed to cpuset_zone_allowed_softwall and the comment is moved to __cpuset_node_allowed_softwall. So fix this comment. Signed-off-by:
SeungHun Lee <waydi1@gmail.com> Acked-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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Jan Kara authored
In case when system contains no dirty pages, wakeup_flusher_threads() will submit WB_SYNC_NONE writeback for 0 pages so wb_writeback() exits immediately without doing anything, even though there are dirty inodes in the system. Thus sync(1) will write all the dirty inodes from a WB_SYNC_ALL writeback pass which is slow. Fix the problem by using get_nr_dirty_pages() in wakeup_flusher_threads() instead of calculating number of dirty pages manually. That function also takes number of dirty inodes into account. Signed-off-by:
Paul Taysom <taysom@chromium.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by:
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Khalid Aziz authored
I am working with a tool that simulates oracle database I/O workload. This tool (orion to be specific - <http://docs.oracle.com/cd/E11882_01/server.112/e16638/iodesign.htm#autoId24>) allocates hugetlbfs pages using shmget() with SHM_HUGETLB flag. It then does aio into these pages from flash disks using various common block sizes used by database. I am looking at performance with two of the most common block sizes - 1M and 64K. aio performance with these two block sizes plunged after Transparent HugePages was introduced in the kernel. Here are performance numbers: pre-THP 2.6.39 3.11-rc5 1M read 8384 MB/s 5629 MB/s 6501 MB/s 64K read 7867 MB/s 4576 MB/s 4251 MB/s I have narrowed the performance impact down to the overheads introduced by THP in __get_page_tail() and put_compound_page() routines. perf top shows >40% of cycles being spent in these two routines. Every time direct I/O to hugetlbfs pages starts, kernel calls get_page() to grab a reference to the pages and calls put_page() when I/O completes to put the reference away. THP introduced significant amount of locking overhead to get_page() and put_page() when dealing with compound pages because hugepages can be split underneath get_page() and put_page(). It added this overhead irrespective of whether it is dealing with hugetlbfs pages or transparent hugepages. This resulted in 20%-45% drop in aio performance when using hugetlbfs pages. Since hugetlbfs pages can not be split, there is no reason to go through all the locking overhead for these pages from what I can see. I added code to __get_page_tail() and put_compound_page() to bypass all the locking code when working with hugetlbfs pages. This improved performance significantly. Performance numbers with this patch: pre-THP 3.11-rc5 3.11-rc5 + Patch 1M read 8384 MB/s 6501 MB/s 8371 MB/s 64K read 7867 MB/s 4251 MB/s 6510 MB/s Performance with 64K read is still lower than what it was before THP, but still a 53% improvement. It does mean there is more work to be done but I will take a 53% improvement for now. Please take a look at the following patch and let me know if it looks reasonable. [akpm@linux-foundation.org: tweak comments] Signed-off-by:
Khalid Aziz <khalid.aziz@oracle.com> Cc: Pravin B Shelar <pshelar@nicira.com> Cc: Christoph Lameter <cl@linux.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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Mel Gorman authored
If kswapd was reclaiming for a high order and resets it to 0 due to fragmentation it will still call compact_pgdat. For the most part, this will fail a compaction_suitable() test and not compact but it is unnecessarily sloppy. It could be fixed in the caller but fix it in the API instead. [dhillf@gmail.com: pointed out that it was a potential problem] Signed-off-by:
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Andrey Vagin authored
The memcg_cache_params structure contains the common part and the union, which represents two different types of data: one for root cashes and another for child caches. The size of child data is fixed. The size of the memcg_caches array is calculated in runtime. Currently the size of memcg_cache_params for root caches is calculated incorrectly, because it includes the size of parameters for child caches. ssize_t size = memcg_caches_array_size(num_groups); size *= sizeof(void *); size += sizeof(struct memcg_cache_params); v2: Fix a typo in calculations Signed-off-by:
Andrey Vagin <avagin@openvz.org> Cc: Glauber Costa <glommer@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:
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Yinghai Lu authored
Current early_pfn_to_nid() on arch that support memblock go over memblock.memory one by one, so will take too many try near the end. We can use existing memblock_search to find the node id for given pfn, that could save some time on bigger system that have many entries memblock.memory array. Here are the timing differences for several machines. In each case with the patch less time was spent in __early_pfn_to_nid(). 3.11-rc5 with patch difference (%) -------- ---------- -------------- UV1: 256 nodes 9TB: 411.66 402.47 -9.19 (2.23%) UV2: 255 nodes 16TB: 1141.02 1138.12 -2.90 (0.25%) UV2: 64 nodes 2TB: 128.15 126.53 -1.62 (1.26%) UV2: 32 nodes 2TB: 121.87 121.07 -0.80 (0.66%) Time in seconds. Signed-off-by:Yinghai Lu <yinghai@kernel.org> Cc: Tejun Heo <tj@kernel.org> Acked-by:
Russ Anderson <rja@sgi.com> Signed-off-by:
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Naoya Horiguchi authored
new_vma_page() is called only by page migration called from do_mbind(), where pages to be migrated are queued into a pagelist by queue_pages_range(). queue_pages_range() confirms that a queued page belongs to some vma, so !vma case is not supposed to be happen. This patch adds BUG_ON() to catch this unexpected case. Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Naoya Horiguchi authored
The function check_range() (and its family) is not well-named, because it does not only checking something, but moving pages from list to list to do page migration for them. So queue_pages_*range is more desirable name. Signed-off-by:
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Naoya Horiguchi authored
Now hugepage migration is enabled, although restricted on pmd-based hugepages for now (due to lack of testing.) So we should allocate migratable hugepages from ZONE_MOVABLE if possible. This patch makes GFP flags in hugepage allocation dependent on migration support, not only the value of hugepages_treat_as_movable. It provides no change on the behavior for architectures which do not support hugepage migration, Signed-off-by:
Andi Kleen <ak@linux.intel.com> Reviewed-by:
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Naoya Horiguchi authored
Currently hugepage migration works well only for pmd-based hugepages (mainly due to lack of testing,) so we had better not enable migration of other levels of hugepages until we are ready for it. Some users of hugepage migration (mbind, move_pages, and migrate_pages) do page table walk and check pud/pmd_huge() there, so they are safe. But the other users (softoffline and memory hotremove) don't do this, so without this patch they can try to migrate unexpected types of hugepages. To prevent this, we introduce hugepage_migration_support() as an architecture dependent check of whether hugepage are implemented on a pmd basis or not. And on some architecture multiple sizes of hugepages are available, so hugepage_migration_support() also checks hugepage size. Signed-off-by:
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Naoya Horiguchi authored
Until now we can't offline memory blocks which contain hugepages because a hugepage is considered as an unmovable page. But now with this patch series, a hugepage has become movable, so by using hugepage migration we can offline such memory blocks. What's different from other users of hugepage migration is that we need to decompose all the hugepages inside the target memory block into free buddy pages after hugepage migration, because otherwise free hugepages remaining in the memory block intervene the memory offlining. For this reason we introduce new functions dissolve_free_huge_page() and dissolve_free_huge_pages(). Other than that, what this patch does is straightforwardly to add hugepage migration code, that is, adding hugepage code to the functions which scan over pfn and collect hugepages to be migrated, and adding a hugepage allocation function to alloc_migrate_target(). As for larger hugepages (1GB for x86_64), it's not easy to do hotremove over them because it's larger than memory block. So we now simply leave it to fail as it is. [yongjun_wei@trendmicro.com.cn: remove duplicated include] Signed-off-by:
Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by:
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