- 07 8月, 2019 1 次提交
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由 Yang Shi 提交于
commit fa1e512fac717f34e7c12d7a384c46e90a647392 upstream. Shakeel Butt reported premature oom on kernel with "cgroup_disable=memory" since mem_cgroup_is_root() returns false even though memcg is actually NULL. The drop_caches is also broken. It is because commit aeed1d32 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") removed the !memcg check before !mem_cgroup_is_root(). And, surprisingly root memcg is allocated even though memory cgroup is disabled by kernel boot parameter. Add mem_cgroup_disabled() check to make reclaimer work as expected. Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com Fixes: aeed1d32 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()") Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com> Reported-by: NShakeel Butt <shakeelb@google.com> Reviewed-by: NShakeel Butt <shakeelb@google.com> Reviewed-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Jan Hadrava <had@kam.mff.cuni.cz> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Roman Gushchin <guro@fb.com> Cc: Hugh Dickins <hughd@google.com> Cc: Qian Cai <cai@lca.pw> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> [4.19+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 28 7月, 2019 1 次提交
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由 Kuo-Hsin Yang 提交于
commit 2c012a4ad1a2cd3fb5a0f9307b9d219f84eda1fa upstream. When file refaults are detected and there are many inactive file pages, the system never reclaim anonymous pages, the file pages are dropped aggressively when there are still a lot of cold anonymous pages and system thrashes. This issue impacts the performance of applications with large executable, e.g. chrome. With this patch, when file refault is detected, inactive_list_is_low() always returns true for file pages in get_scan_count() to enable scanning anonymous pages. The problem can be reproduced by the following test program. ---8<--- void fallocate_file(const char *filename, off_t size) { struct stat st; int fd; if (!stat(filename, &st) && st.st_size >= size) return; fd = open(filename, O_WRONLY | O_CREAT, 0600); if (fd < 0) { perror("create file"); exit(1); } if (posix_fallocate(fd, 0, size)) { perror("fallocate"); exit(1); } close(fd); } long *alloc_anon(long size) { long *start = malloc(size); memset(start, 1, size); return start; } long access_file(const char *filename, long size, long rounds) { int fd, i; volatile char *start1, *end1, *start2; const int page_size = getpagesize(); long sum = 0; fd = open(filename, O_RDONLY); if (fd == -1) { perror("open"); exit(1); } /* * Some applications, e.g. chrome, use a lot of executable file * pages, map some of the pages with PROT_EXEC flag to simulate * the behavior. */ start1 = mmap(NULL, size / 2, PROT_READ | PROT_EXEC, MAP_SHARED, fd, 0); if (start1 == MAP_FAILED) { perror("mmap"); exit(1); } end1 = start1 + size / 2; start2 = mmap(NULL, size / 2, PROT_READ, MAP_SHARED, fd, size / 2); if (start2 == MAP_FAILED) { perror("mmap"); exit(1); } for (i = 0; i < rounds; ++i) { struct timeval before, after; volatile char *ptr1 = start1, *ptr2 = start2; gettimeofday(&before, NULL); for (; ptr1 < end1; ptr1 += page_size, ptr2 += page_size) sum += *ptr1 + *ptr2; gettimeofday(&after, NULL); printf("File access time, round %d: %f (sec) ", i, (after.tv_sec - before.tv_sec) + (after.tv_usec - before.tv_usec) / 1000000.0); } return sum; } int main(int argc, char *argv[]) { const long MB = 1024 * 1024; long anon_mb, file_mb, file_rounds; const char filename[] = "large"; long *ret1; long ret2; if (argc != 4) { printf("usage: thrash ANON_MB FILE_MB FILE_ROUNDS "); exit(0); } anon_mb = atoi(argv[1]); file_mb = atoi(argv[2]); file_rounds = atoi(argv[3]); fallocate_file(filename, file_mb * MB); printf("Allocate %ld MB anonymous pages ", anon_mb); ret1 = alloc_anon(anon_mb * MB); printf("Access %ld MB file pages ", file_mb); ret2 = access_file(filename, file_mb * MB, file_rounds); printf("Print result to prevent optimization: %ld ", *ret1 + ret2); return 0; } ---8<--- Running the test program on 2GB RAM VM with kernel 5.2.0-rc5, the program fills ram with 2048 MB memory, access a 200 MB file for 10 times. Without this patch, the file cache is dropped aggresively and every access to the file is from disk. $ ./thrash 2048 200 10 Allocate 2048 MB anonymous pages Access 200 MB file pages File access time, round 0: 2.489316 (sec) File access time, round 1: 2.581277 (sec) File access time, round 2: 2.487624 (sec) File access time, round 3: 2.449100 (sec) File access time, round 4: 2.420423 (sec) File access time, round 5: 2.343411 (sec) File access time, round 6: 2.454833 (sec) File access time, round 7: 2.483398 (sec) File access time, round 8: 2.572701 (sec) File access time, round 9: 2.493014 (sec) With this patch, these file pages can be cached. $ ./thrash 2048 200 10 Allocate 2048 MB anonymous pages Access 200 MB file pages File access time, round 0: 2.475189 (sec) File access time, round 1: 2.440777 (sec) File access time, round 2: 2.411671 (sec) File access time, round 3: 1.955267 (sec) File access time, round 4: 0.029924 (sec) File access time, round 5: 0.000808 (sec) File access time, round 6: 0.000771 (sec) File access time, round 7: 0.000746 (sec) File access time, round 8: 0.000738 (sec) File access time, round 9: 0.000747 (sec) Checked the swap out stats during the test [1], 19006 pages swapped out with this patch, 3418 pages swapped out without this patch. There are more swap out, but I think it's within reasonable range when file backed data set doesn't fit into the memory. $ ./thrash 2000 100 2100 5 1 # ANON_MB FILE_EXEC FILE_NOEXEC ROUNDS PROCESSES Allocate 2000 MB anonymous pages active_anon: 1613644, inactive_anon: 348656, active_file: 892, inactive_file: 1384 (kB) pswpout: 7972443, pgpgin: 478615246 Access 100 MB executable file pages Access 2100 MB regular file pages File access time, round 0: 12.165, (sec) active_anon: 1433788, inactive_anon: 478116, active_file: 17896, inactive_file: 24328 (kB) File access time, round 1: 11.493, (sec) active_anon: 1430576, inactive_anon: 477144, active_file: 25440, inactive_file: 26172 (kB) File access time, round 2: 11.455, (sec) active_anon: 1427436, inactive_anon: 476060, active_file: 21112, inactive_file: 28808 (kB) File access time, round 3: 11.454, (sec) active_anon: 1420444, inactive_anon: 473632, active_file: 23216, inactive_file: 35036 (kB) File access time, round 4: 11.479, (sec) active_anon: 1413964, inactive_anon: 471460, active_file: 31728, inactive_file: 32224 (kB) pswpout: 7991449 (+ 19006), pgpgin: 489924366 (+ 11309120) With 4 processes accessing non-overlapping parts of a large file, 30316 pages swapped out with this patch, 5152 pages swapped out without this patch. The swapout number is small comparing to pgpgin. [1]: https://github.com/vovo/testing/blob/master/mem_thrash.c Link: http://lkml.kernel.org/r/20190701081038.GA83398@google.com Fixes: e9868505 ("mm,vmscan: only evict file pages when we have plenty") Fixes: 7c5bd705 ("mm: memcg: only evict file pages when we have plenty") Signed-off-by: NKuo-Hsin Yang <vovoy@chromium.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Sonny Rao <sonnyrao@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Rik van Riel <riel@redhat.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> [4.12+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> [backported to 4.14.y, 4.19.y, 5.1.y: adjust context] Signed-off-by: NKuo-Hsin Yang <vovoy@chromium.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 10 7月, 2019 1 次提交
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由 Shakeel Butt 提交于
commit dffcac2cb88e4ec5906235d64a83d802580b119e upstream. In production we have noticed hard lockups on large machines running large jobs due to kswaps hoarding lru lock within isolate_lru_pages when sc->reclaim_idx is 0 which is a small zone. The lru was couple hundred GiBs and the condition (page_zonenum(page) > sc->reclaim_idx) in isolate_lru_pages() was basically skipping GiBs of pages while holding the LRU spinlock with interrupt disabled. On further inspection, it seems like there are two issues: (1) If kswapd on the return from balance_pgdat() could not sleep (i.e. node is still unbalanced), the classzone_idx is unintentionally set to 0 and the whole reclaim cycle of kswapd will try to reclaim only the lowest and smallest zone while traversing the whole memory. (2) Fundamentally isolate_lru_pages() is really bad when the allocation has woken kswapd for a smaller zone on a very large machine running very large jobs. It can hoard the LRU spinlock while skipping over 100s of GiBs of pages. This patch only fixes (1). (2) needs a more fundamental solution. To fix (1), in the kswapd context, if pgdat->kswapd_classzone_idx is invalid use the classzone_idx of the previous kswapd loop otherwise use the one the waker has requested. Link: http://lkml.kernel.org/r/20190701201847.251028-1-shakeelb@google.com Fixes: e716f2eb ("mm, vmscan: prevent kswapd sleeping prematurely due to mismatched classzone_idx") Signed-off-by: NShakeel Butt <shakeelb@google.com> Reviewed-by: NYang Shi <yang.shi@linux.alibaba.com> Acked-by: NMel Gorman <mgorman@techsingularity.net> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hdanton@sina.com> Cc: Roman Gushchin <guro@fb.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 19 6月, 2019 1 次提交
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由 Minchan Kim 提交于
commit a58f2cef26e1ca44182c8b22f4f4395e702a5795 upstream. There was the below bug report from Wu Fangsuo. On the CMA allocation path, isolate_migratepages_range() could isolate unevictable LRU pages and reclaim_clean_page_from_list() can try to reclaim them if they are clean file-backed pages. page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24 flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked) raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053 raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80 page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page)) page->mem_cgroup:ffffffc09bf3ee80 ------------[ cut here ]------------ kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S 4.14.81 #3 Hardware name: ASR AQUILAC EVB (DT) task: ffffffc00a54cd00 task.stack: ffffffc009b00000 PC is at shrink_page_list+0x1998/0x3240 LR is at shrink_page_list+0x1998/0x3240 pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045 sp : ffffffc009b05940 .. shrink_page_list+0x1998/0x3240 reclaim_clean_pages_from_list+0x3c0/0x4f0 alloc_contig_range+0x3bc/0x650 cma_alloc+0x214/0x668 ion_cma_allocate+0x98/0x1d8 ion_alloc+0x200/0x7e0 ion_ioctl+0x18c/0x378 do_vfs_ioctl+0x17c/0x1780 SyS_ioctl+0xac/0xc0 Wu found it's due to commit ad6b6704 ("mm: remove SWAP_MLOCK in ttu"). Before that, unevictable pages go to cull_mlocked so that we can't reach the VM_BUG_ON_PAGE line. To fix the issue, this patch filters out unevictable LRU pages from the reclaim_clean_pages_from_list in CMA. Link: http://lkml.kernel.org/r/20190524071114.74202-1-minchan@kernel.org Fixes: ad6b6704 ("mm: remove SWAP_MLOCK in ttu") Signed-off-by: NMinchan Kim <minchan@kernel.org> Reported-by: NWu Fangsuo <fangsuowu@asrmicro.com> Debugged-by: NWu Fangsuo <fangsuowu@asrmicro.com> Tested-by: NWu Fangsuo <fangsuowu@asrmicro.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Pankaj Suryawanshi <pankaj.suryawanshi@einfochips.com> Cc: <stable@vger.kernel.org> [4.12+] Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 17 5月, 2019 1 次提交
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由 Johannes Weiner 提交于
[ Upstream commit 3b991208b897f52507168374033771a984b947b1 ] During !CONFIG_CGROUP reclaim, we expand the inactive list size if it's thrashing on the node that is about to be reclaimed. But when cgroups are enabled, we suddenly ignore the node scope and use the cgroup scope only. The result is that pressure bleeds between NUMA nodes depending on whether cgroups are merely compiled into Linux. This behavioral difference is unexpected and undesirable. When the refault adaptivity of the inactive list was first introduced, there were no statistics at the lruvec level - the intersection of node and memcg - so it was better than nothing. But now that we have that infrastructure, use lruvec_page_state() to make the list balancing decision always NUMA aware. [hannes@cmpxchg.org: fix bisection hole] Link: http://lkml.kernel.org/r/20190417155241.GB23013@cmpxchg.org Link: http://lkml.kernel.org/r/20190412144438.2645-1-hannes@cmpxchg.org Fixes: 2a2e4885 ("mm: vmscan: fix IO/refault regression in cache workingset transition") Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reviewed-by: NShakeel Butt <shakeelb@google.com> Cc: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NSasha Levin <sashal@kernel.org>
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- 20 2月, 2019 1 次提交
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由 Dave Chinner 提交于
commit a9a238e83fbb0df31c3b9b67003f8f9d1d1b6c96 upstream. This reverts commit 172b06c3 ("mm: slowly shrink slabs with a relatively small number of objects"). This change changes the agressiveness of shrinker reclaim, causing small cache and low priority reclaim to greatly increase scanning pressure on small caches. As a result, light memory pressure has a disproportionate affect on small caches, and causes large caches to be reclaimed much faster than previously. As a result, it greatly perturbs the delicate balance of the VFS caches (dentry/inode vs file page cache) such that the inode/dentry caches are reclaimed much, much faster than the page cache and this drives us into several other caching imbalance related problems. As such, this is a bad change and needs to be reverted. [ Needs some massaging to retain the later seekless shrinker modifications.] Link: http://lkml.kernel.org/r/20190130041707.27750-3-david@fromorbit.com Fixes: 172b06c3 ("mm: slowly shrink slabs with a relatively small number of objects") Signed-off-by: NDave Chinner <dchinner@redhat.com> Cc: Wolfgang Walter <linux@stwm.de> Cc: Roman Gushchin <guro@fb.com> Cc: Spock <dairinin@gmail.com> Cc: Rik van Riel <riel@surriel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 29 12月, 2018 1 次提交
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由 Roman Gushchin 提交于
commit 68600f623d69da428c6163275f97ca126e1a8ec5 upstream. I've noticed, that dying memory cgroups are often pinned in memory by a single pagecache page. Even under moderate memory pressure they sometimes stayed in such state for a long time. That looked strange. My investigation showed that the problem is caused by applying the LRU pressure balancing math: scan = div64_u64(scan * fraction[lru], denominator), where denominator = fraction[anon] + fraction[file] + 1. Because fraction[lru] is always less than denominator, if the initial scan size is 1, the result is always 0. This means the last page is not scanned and has no chances to be reclaimed. Fix this by rounding up the result of the division. In practice this change significantly improves the speed of dying cgroups reclaim. [guro@fb.com: prevent double calculation of DIV64_U64_ROUND_UP() arguments] Link: http://lkml.kernel.org/r/20180829213311.GA13501@castle Link: http://lkml.kernel.org/r/20180827162621.30187-3-guro@fb.comSigned-off-by: NRoman Gushchin <guro@fb.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 06 10月, 2018 1 次提交
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由 Kirill Tkhai 提交于
do_shrink_slab() returns unsigned long value, and the placing into int variable cuts high bytes off. Then we compare ret and 0xfffffffe (since SHRINK_EMPTY is converted to ret type). Thus a large number of objects returned by do_shrink_slab() may be interpreted as SHRINK_EMPTY, if low bytes of their value are equal to 0xfffffffe. Fix that by declaration ret as unsigned long in these functions. Link: http://lkml.kernel.org/r/153813407177.17544.14888305435570723973.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Reported-by: NCyrill Gorcunov <gorcunov@openvz.org> Acked-by: NCyrill Gorcunov <gorcunov@openvz.org> Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 21 9月, 2018 1 次提交
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由 Roman Gushchin 提交于
9092c71b ("mm: use sc->priority for slab shrink targets") changed the way that the target slab pressure is calculated and made it priority-based: delta = freeable >> priority; delta *= 4; do_div(delta, shrinker->seeks); The problem is that on a default priority (which is 12) no pressure is applied at all, if the number of potentially reclaimable objects is less than 4096 (1<<12). This causes the last objects on slab caches of no longer used cgroups to (almost) never get reclaimed. It's obviously a waste of memory. It can be especially painful, if these stale objects are holding a reference to a dying cgroup. Slab LRU lists are reparented on memcg offlining, but corresponding objects are still holding a reference to the dying cgroup. If we don't scan these objects, the dying cgroup can't go away. Most likely, the parent cgroup hasn't any directly charged objects, only remaining objects from dying children cgroups. So it can easily hold a reference to hundreds of dying cgroups. If there are no big spikes in memory pressure, and new memory cgroups are created and destroyed periodically, this causes the number of dying cgroups grow steadily, causing a slow-ish and hard-to-detect memory "leak". It's not a real leak, as the memory can be eventually reclaimed, but it could not happen in a real life at all. I've seen hosts with a steadily climbing number of dying cgroups, which doesn't show any signs of a decline in months, despite the host is loaded with a production workload. It is an obvious waste of memory, and to prevent it, let's apply a minimal pressure even on small shrinker lists. E.g. if there are freeable objects, let's scan at least min(freeable, scan_batch) objects. This fix significantly improves a chance of a dying cgroup to be reclaimed, and together with some previous patches stops the steady growth of the dying cgroups number on some of our hosts. Link: http://lkml.kernel.org/r/20180905230759.12236-1-guro@fb.com Fixes: 9092c71b ("mm: use sc->priority for slab shrink targets") Signed-off-by: NRoman Gushchin <guro@fb.com> Acked-by: NRik van Riel <riel@surriel.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 23 8月, 2018 2 次提交
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由 Jiang Biao 提交于
page_freeze_refs/page_unfreeze_refs have already been relplaced by page_ref_freeze/page_ref_unfreeze , but they are not modified in the comments. Link: http://lkml.kernel.org/r/1532590226-106038-1-git-send-email-jiang.biao2@zte.com.cnSigned-off-by: NJiang Biao <jiang.biao2@zte.com.cn> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
There is a sad BUG introduced in patch adding SHRINKER_REGISTERING. shrinker_idr business is only for memcg-aware shrinkers. Only such type of shrinkers have id and they must be finaly installed via idr_replace() in this function. For !memcg-aware shrinkers we never initialize shrinker->id field. But there are all types of shrinkers passed to idr_replace(), and every !memcg-aware shrinker with random ID (most probably, its id is 0) replaces memcg-aware shrinker pointed by the ID in IDR. This patch fixes the problem. Link: http://lkml.kernel.org/r/8ff8a793-8211-713a-4ed9-d6e52390c2fc@virtuozzo.com Fixes: 7e010df5 "mm: use special value SHRINKER_REGISTERING instead of list_empty() check" Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Reported-by: <syzbot+d5f648a1bfe15678786b@syzkaller.appspotmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Shakeel Butt <shakeelb@google.com> Cc: <syzkaller-bugs@googlegroups.com> Cc: Huang Ying <ying.huang@intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 18 8月, 2018 9 次提交
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由 Kirill Tkhai 提交于
The patch introduces a special value SHRINKER_REGISTERING to use instead of list_empty() to differ a registering shrinker from unregistered shrinker. Why we need that at all? Shrinker registration is split in two parts. The first one is prealloc_shrinker(), which allocates shrinker memory and reserves ID in shrinker_idr. This function can fail. The second is register_shrinker_prepared(), and it finalizes the registration. This function actually makes shrinker available to be used from shrink_slab(), and it can't fail. One shrinker may be based on more then one LRU lists. So, we never clear the bit in memcg shrinker maps, when (one of) corresponding LRU list becomes empty, since other LRU lists may be not empty. See superblock shrinker for example: it is based on two LRU lists: s_inode_lru and s_dentry_lru. We do not want to clear shrinker bit, when there are no inodes in s_inode_lru, as s_dentry_lru may contain dentries. Instead of that, we use special algorithm to detect shrinkers having no elements at all its LRU lists, and this is made in shrink_slab_memcg(). See the comment in this function for the details. Also, in shrink_slab_memcg() we clear shrinker bit in the map, when we meet unregistered shrinker (bit is set, while there is no a shrinker in IDR). Otherwise, we would have done that at the moment of shrinker unregistration for all memcgs (and this looks worse, since iteration over all memcg may take much time). Also this would have imposed restrictions on shrinker unregistration order for its users: they would have had to guarantee, there are no new elements after unregister_shrinker() (otherwise, a new added element would have set a bit). So, if we meet a set bit in map and no shrinker in IDR when we're iterating over the map in shrink_slab_memcg(), this means the corresponding shrinker is unregistered, and we must clear the bit. Another case is shrinker registration. We want two things there: 1) do_shrink_slab() can be called only for completely registered shrinkers; 2) shrinker internal lists may be populated in any order with register_shrinker_prepared() (let's talk on the example with sb). Both of: a)list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru); [cpu0] memcg_set_shrinker_bit(); [cpu0] ... register_shrinker_prepared(); [cpu1] and b)register_shrinker_prepared(); [cpu0] ... list_lru_add(&inode->i_sb->s_inode_lru, &inode->i_lru); [cpu1] memcg_set_shrinker_bit(); [cpu1] are legitimate. We don't want to impose restriction here and to force people to use only (b) variant. We don't want to force people to care, there is no elements in LRU lists before the shrinker is completely registered. Internal users of LRU lists and shrinker code are two different subsystems, and they have to be closed in themselves each other. In (a) case we have the bit set before shrinker is completely registered. We don't want do_shrink_slab() is called at this moment, so we have to detect such the registering shrinkers. Before this patch list_empty() (shrinker is not linked to the list) check was used for that. So, in (a) there could be a bit set, but we don't call do_shrink_slab() unless shrinker is linked to the list. It's just an indicator, I just overloaded linking to the list. This was not the best solution, since it's better not to touch the shrinker memory from shrink_slab_memcg() before it's completely registered (this also will be useful in the future to make shrink_slab() completely lockless). So, this patch introduces better way to detect registering shrinker, which allows not to dereference shrinker memory. It's just a ~0UL value, which we insert into the IDR during ID allocation. After shrinker is ready to be used, we insert actual shrinker pointer in the IDR, and it becomes available to shrink_slab_memcg(). We can't use NULL instead of this new value for this purpose as: shrink_slab_memcg() already uses NULL to detect unregistered shrinkers, and we don't want the function sees NULL and clears the bit, otherwise (a) won't work. This is the only thing the patch makes: the better way to detect registering shrinker. Nothing else this patch makes. Also this gives a better assembler, but it's minor side of the patch: Before: callq <idr_find> mov %rax,%r15 test %rax,%rax je <shrink_slab_memcg+0x1d5> mov 0x20(%rax),%rax lea 0x20(%r15),%rdx cmp %rax,%rdx je <shrink_slab_memcg+0xbd> mov 0x8(%rsp),%edx mov %r15,%rsi lea 0x10(%rsp),%rdi callq <do_shrink_slab> After: callq <idr_find> mov %rax,%r15 lea -0x1(%rax),%rax cmp $0xfffffffffffffffd,%rax ja <shrink_slab_memcg+0x1cd> mov 0x8(%rsp),%edx mov %r15,%rsi lea 0x10(%rsp),%rdi callq ffffffff810cefd0 <do_shrink_slab> [ktkhai@virtuozzo.com: add #ifdef CONFIG_MEMCG_KMEM around idr_replace()] Link: http://lkml.kernel.org/r/758b8fec-7573-47eb-b26a-7b2847ae7b8c@virtuozzo.com Link: http://lkml.kernel.org/r/153355467546.11522.4518015068123480218.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Matthew Wilcox <willy@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Josef Bacik <jbacik@fb.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
In case of shrink_slab_memcg() we do not zero nid, when shrinker is not numa-aware. This is not a real problem, since currently all memcg-aware shrinkers are numa-aware too (we have two: super_block shrinker and workingset shrinker), but something may change in the future. Link: http://lkml.kernel.org/r/153320759911.18959.8842396230157677671.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Matthew Wilcox <willy@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Josef Bacik <jbacik@fb.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
To avoid further unneed calls of do_shrink_slab() for shrinkers, which already do not have any charged objects in a memcg, their bits have to be cleared. This patch introduces a lockless mechanism to do that without races without parallel list lru add. After do_shrink_slab() returns SHRINK_EMPTY the first time, we clear the bit and call it once again. Then we restore the bit, if the new return value is different. Note, that single smp_mb__after_atomic() in shrink_slab_memcg() covers two situations: 1)list_lru_add() shrink_slab_memcg list_add_tail() for_each_set_bit() <--- read bit do_shrink_slab() <--- missed list update (no barrier) <MB> <MB> set_bit() do_shrink_slab() <--- seen list update This situation, when the first do_shrink_slab() sees set bit, but it doesn't see list update (i.e., race with the first element queueing), is rare. So we don't add <MB> before the first call of do_shrink_slab() instead of this to do not slow down generic case. Also, it's need the second call as seen in below in (2). 2)list_lru_add() shrink_slab_memcg() list_add_tail() ... set_bit() ... ... for_each_set_bit() do_shrink_slab() do_shrink_slab() clear_bit() ... ... ... list_lru_add() ... list_add_tail() clear_bit() <MB> <MB> set_bit() do_shrink_slab() The barriers guarantee that the second do_shrink_slab() in the right side task sees list update if really cleared the bit. This case is drawn in the code comment. [Results/performance of the patchset] After the whole patchset applied the below test shows signify increase of performance: $echo 1 > /sys/fs/cgroup/memory/memory.use_hierarchy $mkdir /sys/fs/cgroup/memory/ct $echo 4000M > /sys/fs/cgroup/memory/ct/memory.kmem.limit_in_bytes $for i in `seq 0 4000`; do mkdir /sys/fs/cgroup/memory/ct/$i; echo $$ > /sys/fs/cgroup/memory/ct/$i/cgroup.procs; mkdir -p s/$i; mount -t tmpfs $i s/$i; touch s/$i/file; done Then, 5 sequential calls of drop caches: $time echo 3 > /proc/sys/vm/drop_caches 1)Before: 0.00user 13.78system 0:13.78elapsed 99%CPU 0.00user 5.59system 0:05.60elapsed 99%CPU 0.00user 5.48system 0:05.48elapsed 99%CPU 0.00user 8.35system 0:08.35elapsed 99%CPU 0.00user 8.34system 0:08.35elapsed 99%CPU 2)After 0.00user 1.10system 0:01.10elapsed 99%CPU 0.00user 0.00system 0:00.01elapsed 64%CPU 0.00user 0.01system 0:00.01elapsed 82%CPU 0.00user 0.00system 0:00.01elapsed 64%CPU 0.00user 0.01system 0:00.01elapsed 82%CPU The results show the performance increases at least in 548 times. Shakeel Butt tested this patchset with fork-bomb on his configuration: > I created 255 memcgs, 255 ext4 mounts and made each memcg create a > file containing few KiBs on corresponding mount. Then in a separate > memcg of 200 MiB limit ran a fork-bomb. > > I ran the "perf record -ag -- sleep 60" and below are the results: > > Without the patch series: > Samples: 4M of event 'cycles', Event count (approx.): 3279403076005 > + 36.40% fb.sh [kernel.kallsyms] [k] shrink_slab > + 18.97% fb.sh [kernel.kallsyms] [k] list_lru_count_one > + 6.75% fb.sh [kernel.kallsyms] [k] super_cache_count > + 0.49% fb.sh [kernel.kallsyms] [k] down_read_trylock > + 0.44% fb.sh [kernel.kallsyms] [k] mem_cgroup_iter > + 0.27% fb.sh [kernel.kallsyms] [k] up_read > + 0.21% fb.sh [kernel.kallsyms] [k] osq_lock > + 0.13% fb.sh [kernel.kallsyms] [k] shmem_unused_huge_count > + 0.08% fb.sh [kernel.kallsyms] [k] shrink_node_memcg > + 0.08% fb.sh [kernel.kallsyms] [k] shrink_node > > With the patch series: > Samples: 4M of event 'cycles', Event count (approx.): 2756866824946 > + 47.49% fb.sh [kernel.kallsyms] [k] down_read_trylock > + 30.72% fb.sh [kernel.kallsyms] [k] up_read > + 9.51% fb.sh [kernel.kallsyms] [k] mem_cgroup_iter > + 1.69% fb.sh [kernel.kallsyms] [k] shrink_node_memcg > + 1.35% fb.sh [kernel.kallsyms] [k] mem_cgroup_protected > + 1.05% fb.sh [kernel.kallsyms] [k] queued_spin_lock_slowpath > + 0.85% fb.sh [kernel.kallsyms] [k] _raw_spin_lock > + 0.78% fb.sh [kernel.kallsyms] [k] lruvec_lru_size > + 0.57% fb.sh [kernel.kallsyms] [k] shrink_node > + 0.54% fb.sh [kernel.kallsyms] [k] queue_work_on > + 0.46% fb.sh [kernel.kallsyms] [k] shrink_slab_memcg [ktkhai@virtuozzo.com: v9] Link: http://lkml.kernel.org/r/153112561772.4097.11011071937553113003.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/153063070859.1818.11870882950920963480.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
We need to distinguish the situations when shrinker has very small amount of objects (see vfs_pressure_ratio() called from super_cache_count()), and when it has no objects at all. Currently, in the both of these cases, shrinker::count_objects() returns 0. The patch introduces new SHRINK_EMPTY return value, which will be used for "no objects at all" case. It's is a refactoring mostly, as SHRINK_EMPTY is replaced by 0 by all callers of do_shrink_slab() in this patch, and all the magic will happen in further. Link: http://lkml.kernel.org/r/153063069574.1818.11037751256699341813.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Vladimir Davydov 提交于
The patch makes shrink_slab() be called for root_mem_cgroup in the same way as it's called for the rest of cgroups. This simplifies the logic and improves the readability. [ktkhai@virtuozzo.com: wrote changelog] Link: http://lkml.kernel.org/r/153063068338.1818.11496084754797453962.stgit@localhost.localdomainSigned-off-by: NVladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
Using the preparations made in previous patches, in case of memcg shrink, we may avoid shrinkers, which are not set in memcg's shrinkers bitmap. To do that, we separate iterations over memcg-aware and !memcg-aware shrinkers, and memcg-aware shrinkers are chosen via for_each_set_bit() from the bitmap. In case of big nodes, having many isolated environments, this gives significant performance growth. See next patches for the details. Note that the patch does not respect to empty memcg shrinkers, since we never clear the bitmap bits after we set it once. Their shrinkers will be called again, with no shrinked objects as result. This functionality is provided by next patches. [ktkhai@virtuozzo.com: v9] Link: http://lkml.kernel.org/r/153112558507.4097.12713813335683345488.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/153063066653.1818.976035462801487910.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
Imagine a big node with many cpus, memory cgroups and containers. Let we have 200 containers, every container has 10 mounts, and 10 cgroups. All container tasks don't touch foreign containers mounts. If there is intensive pages write, and global reclaim happens, a writing task has to iterate over all memcgs to shrink slab, before it's able to go to shrink_page_list(). Iteration over all the memcg slabs is very expensive: the task has to visit 200 * 10 = 2000 shrinkers for every memcg, and since there are 2000 memcgs, the total calls are 2000 * 2000 = 4000000. So, the shrinker makes 4 million do_shrink_slab() calls just to try to isolate SWAP_CLUSTER_MAX pages in one of the actively writing memcg via shrink_page_list(). I've observed a node spending almost 100% in kernel, making useless iteration over already shrinked slab. This patch adds bitmap of memcg-aware shrinkers to memcg. The size of the bitmap depends on bitmap_nr_ids, and during memcg life it's maintained to be enough to fit bitmap_nr_ids shrinkers. Every bit in the map is related to corresponding shrinker id. Next patches will maintain set bit only for really charged memcg. This will allow shrink_slab() to increase its performance in significant way. See the last patch for the numbers. [ktkhai@virtuozzo.com: v9] Link: http://lkml.kernel.org/r/153112549031.4097.3576147070498769979.stgit@localhost.localdomain [ktkhai@virtuozzo.com: add comment to mem_cgroup_css_online()] Link: http://lkml.kernel.org/r/521f9e5f-c436-b388-fe83-4dc870bfb489@virtuozzo.com Link: http://lkml.kernel.org/r/153063056619.1818.12550500883688681076.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kirill Tkhai 提交于
Introduce shrinker::id number, which is used to enumerate memcg-aware shrinkers. The number start from 0, and the code tries to maintain it as small as possible. This will be used to represent a memcg-aware shrinkers in memcg shrinkers map. Since all memcg-aware shrinkers are based on list_lru, which is per-memcg in case of !CONFIG_MEMCG_KMEM only, the new functionality will be under this config option. [ktkhai@virtuozzo.com: v9] Link: http://lkml.kernel.org/r/153112546435.4097.10607140323811756557.stgit@localhost.localdomain Link: http://lkml.kernel.org/r/153063054586.1818.6041047871606697364.stgit@localhost.localdomainSigned-off-by: NKirill Tkhai <ktkhai@virtuozzo.com> Acked-by: NVladimir Davydov <vdavydov.dev@gmail.com> Tested-by: NShakeel Butt <shakeelb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guenter Roeck <linux@roeck-us.net> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <jbacik@fb.com> Cc: Li RongQing <lirongqing@baidu.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matthias Kaehlcke <mka@chromium.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Roman Gushchin <guro@fb.com> Cc: Sahitya Tummala <stummala@codeaurora.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Greg Thelen 提交于
Use smaller scan_control fields for order, priority, and reclaim_idx. Convert fields from int => s8. All easily fit within a byte: - allocation order range: 0..MAX_ORDER(64?) - priority range: 0..12(DEF_PRIORITY) - reclaim_idx range: 0..6(__MAX_NR_ZONES) Since 6538b8ea ("x86_64: expand kernel stack to 16K") x86_64 stack overflows are not an issue. But it's inefficient to use ints. Use s8 (signed byte) rather than u8 to allow for loops like: do { ... } while (--sc.priority >= 0); Add BUILD_BUG_ON to verify that s8 is capable of storing max values. This reduces sizeof(struct scan_control): - 96 => 80 bytes (x86_64) - 68 => 56 bytes (i386) scan_control structure field order is changed to utilize padding. After this patch there is 1 bit of scan_control padding. akpm: makes my vmscan.o's .text 572 bytes smaller as well. Link: http://lkml.kernel.org/r/20180530061212.84915-1-gthelen@google.comSigned-off-by: NGreg Thelen <gthelen@google.com> Suggested-by: NMatthew Wilcox <willy@infradead.org> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 08 6月, 2018 2 次提交
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由 Roman Gushchin 提交于
Memory controller implements the memory.low best-effort memory protection mechanism, which works perfectly in many cases and allows protecting working sets of important workloads from sudden reclaim. But its semantics has a significant limitation: it works only as long as there is a supply of reclaimable memory. This makes it pretty useless against any sort of slow memory leaks or memory usage increases. This is especially true for swapless systems. If swap is enabled, memory soft protection effectively postpones problems, allowing a leaking application to fill all swap area, which makes no sense. The only effective way to guarantee the memory protection in this case is to invoke the OOM killer. It's possible to handle this case in userspace by reacting on MEMCG_LOW events; but there is still a place for a fail-safe in-kernel mechanism to provide stronger guarantees. This patch introduces the memory.min interface for cgroup v2 memory controller. It works very similarly to memory.low (sharing the same hierarchical behavior), except that it's not disabled if there is no more reclaimable memory in the system. If cgroup is not populated, its memory.min is ignored, because otherwise even the OOM killer wouldn't be able to reclaim the protected memory, and the system can stall. [guro@fb.com: s/low/min/ in docs] Link: http://lkml.kernel.org/r/20180510130758.GA9129@castle.DHCP.thefacebook.com Link: http://lkml.kernel.org/r/20180509180734.GA4856@castle.DHCP.thefacebook.comSigned-off-by: NRoman Gushchin <guro@fb.com> Reviewed-by: NRandy Dunlap <rdunlap@infradead.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Omar Sandoval 提交于
While revisiting my Btrfs swapfile series [1], I introduced a situation in which reclaim would lock i_rwsem, and even though the swapon() path clearly made GFP_KERNEL allocations while holding i_rwsem, I got no complaints from lockdep. It turns out that the rework of the fs_reclaim annotation was broken: if the current task has PF_MEMALLOC set, we don't acquire the dummy fs_reclaim lock, but when reclaiming we always check this _after_ we've just set the PF_MEMALLOC flag. In most cases, we can fix this by moving the fs_reclaim_{acquire,release}() outside of the memalloc_noreclaim_{save,restore}(), althought kswapd is slightly different. After applying this, I got the expected lockdep splats. 1: https://lwn.net/Articles/625412/ Link: http://lkml.kernel.org/r/9f8aa70652a98e98d7c4de0fc96a4addcee13efe.1523778026.git.osandov@fb.com Fixes: d92a8cfc ("locking/lockdep: Rework FS_RECLAIM annotation") Signed-off-by: NOmar Sandoval <osandov@fb.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 6月, 2018 1 次提交
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由 Hugh Dickins 提交于
George Boole would have noticed a slight error in 4.16 commit 69d763fc ("mm: pin address_space before dereferencing it while isolating an LRU page"). Fix it, to match both the comment above it, and the original behaviour. Although anonymous pages are not marked PageDirty at first, we have an old habit of calling SetPageDirty when a page is removed from swap cache: so there's a category of ex-swap pages that are easily migratable, but were inadvertently excluded from compaction's async migration in 4.16. Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1805302014001.12558@eggly.anvils Fixes: 69d763fc ("mm: pin address_space before dereferencing it while isolating an LRU page") Signed-off-by: NHugh Dickins <hughd@google.com> Acked-by: NMinchan Kim <minchan@kernel.org> Acked-by: NMel Gorman <mgorman@techsingularity.net> Reported-by: NIvan Kalvachev <ikalvachev@gmail.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 16 4月, 2018 1 次提交
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由 Tetsuo Handa 提交于
syzbot is catching so many bugs triggered by commit 9ee332d9 ("sget(): handle failures of register_shrinker()"). That commit expected that calling kill_sb() from deactivate_locked_super() without successful fill_super() is safe, but the reality was different; some callers assign attributes which are needed for kill_sb() after sget() succeeds. For example, [1] is a report where sb->s_mode (which seems to be either FMODE_READ | FMODE_EXCL | FMODE_WRITE or FMODE_READ | FMODE_EXCL) is not assigned unless sget() succeeds. But it does not worth complicate sget() so that register_shrinker() failure path can safely call kill_block_super() via kill_sb(). Making alloc_super() fail if memory allocation for register_shrinker() failed is much simpler. Let's avoid calling deactivate_locked_super() from sget_userns() by preallocating memory for the shrinker and making register_shrinker() in sget_userns() never fail. [1] https://syzkaller.appspot.com/bug?id=588996a25a2587be2e3a54e8646728fb9cae44e7Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Nsyzbot <syzbot+5a170e19c963a2e0df79@syzkaller.appspotmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
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- 12 4月, 2018 7 次提交
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由 Matthew Wilcox 提交于
Remove the address_space ->tree_lock and use the xa_lock newly added to the radix_tree_root. Rename the address_space ->page_tree to ->i_pages, since we don't really care that it's a tree. [willy@infradead.org: fix nds32, fs/dax.c] Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com> Acked-by: NJeff Layton <jlayton@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Johannes Weiner 提交于
Commit a983b5eb ("mm: memcontrol: fix excessive complexity in memory.stat reporting") added per-cpu drift to all memory cgroup stats and events shown in memory.stat and memory.events. For memory.stat this is acceptable. But memory.events issues file notifications, and somebody polling the file for changes will be confused when the counters in it are unchanged after a wakeup. Luckily, the events in memory.events - MEMCG_LOW, MEMCG_HIGH, MEMCG_MAX, MEMCG_OOM - are sufficiently rare and high-level that we don't need per-cpu buffering for them: MEMCG_HIGH and MEMCG_MAX would be the most frequent, but they're counting invocations of reclaim, which is a complex operation that touches many shared cachelines. This splits memory.events from the generic VM events and tracks them in their own, unbuffered atomic counters. That's also cleaner, as it eliminates the ugly enum nesting of VM and cgroup events. [hannes@cmpxchg.org: "array subscript is above array bounds"] Link: http://lkml.kernel.org/r/20180406155441.GA20806@cmpxchg.org Link: http://lkml.kernel.org/r/20180405175507.GA24817@cmpxchg.org Fixes: a983b5eb ("mm: memcontrol: fix excessive complexity in memory.stat reporting") Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org> Reported-by: NTejun Heo <tj@kernel.org> Acked-by: NTejun Heo <tj@kernel.org> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Roman Gushchin <guro@fb.com> Cc: Rik van Riel <riel@surriel.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Steven Rostedt 提交于
The trace event trace_mm_vmscan_lru_shrink_inactive() currently has 12 parameters! Seven of them are from the reclaim_stat structure. This structure is currently local to mm/vmscan.c. By moving it to the global vmstat.h header, we can also reference it from the vmscan tracepoints. In moving it, it brings down the overhead of passing so many arguments to the trace event. In the future, we may limit the number of arguments that a trace event may pass (ideally just 6, but more realistically it may be 8). Before this patch, the code to call the trace event is this: 0f 83 aa fe ff ff jae ffffffff811e6261 <shrink_inactive_list+0x1e1> 48 8b 45 a0 mov -0x60(%rbp),%rax 45 8b 64 24 20 mov 0x20(%r12),%r12d 44 8b 6d d4 mov -0x2c(%rbp),%r13d 8b 4d d0 mov -0x30(%rbp),%ecx 44 8b 75 cc mov -0x34(%rbp),%r14d 44 8b 7d c8 mov -0x38(%rbp),%r15d 48 89 45 90 mov %rax,-0x70(%rbp) 8b 83 b8 fe ff ff mov -0x148(%rbx),%eax 8b 55 c0 mov -0x40(%rbp),%edx 8b 7d c4 mov -0x3c(%rbp),%edi 8b 75 b8 mov -0x48(%rbp),%esi 89 45 80 mov %eax,-0x80(%rbp) 65 ff 05 e4 f7 e2 7e incl %gs:0x7ee2f7e4(%rip) # 15bd0 <__preempt_count> 48 8b 05 75 5b 13 01 mov 0x1135b75(%rip),%rax # ffffffff8231bf68 <__tracepoint_mm_vmscan_lru_shrink_inactive+0x28> 48 85 c0 test %rax,%rax 74 72 je ffffffff811e646a <shrink_inactive_list+0x3ea> 48 89 c3 mov %rax,%rbx 4c 8b 10 mov (%rax),%r10 89 f8 mov %edi,%eax 48 89 85 68 ff ff ff mov %rax,-0x98(%rbp) 89 f0 mov %esi,%eax 48 89 85 60 ff ff ff mov %rax,-0xa0(%rbp) 89 c8 mov %ecx,%eax 48 89 85 78 ff ff ff mov %rax,-0x88(%rbp) 89 d0 mov %edx,%eax 48 89 85 70 ff ff ff mov %rax,-0x90(%rbp) 8b 45 8c mov -0x74(%rbp),%eax 48 8b 7b 08 mov 0x8(%rbx),%rdi 48 83 c3 18 add $0x18,%rbx 50 push %rax 41 54 push %r12 41 55 push %r13 ff b5 78 ff ff ff pushq -0x88(%rbp) 41 56 push %r14 41 57 push %r15 ff b5 70 ff ff ff pushq -0x90(%rbp) 4c 8b 8d 68 ff ff ff mov -0x98(%rbp),%r9 4c 8b 85 60 ff ff ff mov -0xa0(%rbp),%r8 48 8b 4d 98 mov -0x68(%rbp),%rcx 48 8b 55 90 mov -0x70(%rbp),%rdx 8b 75 80 mov -0x80(%rbp),%esi 41 ff d2 callq *%r10 After the patch: 0f 83 a8 fe ff ff jae ffffffff811e626d <shrink_inactive_list+0x1cd> 8b 9b b8 fe ff ff mov -0x148(%rbx),%ebx 45 8b 64 24 20 mov 0x20(%r12),%r12d 4c 8b 6d a0 mov -0x60(%rbp),%r13 65 ff 05 f5 f7 e2 7e incl %gs:0x7ee2f7f5(%rip) # 15bd0 <__preempt_count> 4c 8b 35 86 5b 13 01 mov 0x1135b86(%rip),%r14 # ffffffff8231bf68 <__tracepoint_mm_vmscan_lru_shrink_inactive+0x28> 4d 85 f6 test %r14,%r14 74 2a je ffffffff811e6411 <shrink_inactive_list+0x371> 49 8b 06 mov (%r14),%rax 8b 4d 8c mov -0x74(%rbp),%ecx 49 8b 7e 08 mov 0x8(%r14),%rdi 49 83 c6 18 add $0x18,%r14 4c 89 ea mov %r13,%rdx 45 89 e1 mov %r12d,%r9d 4c 8d 45 b8 lea -0x48(%rbp),%r8 89 de mov %ebx,%esi 51 push %rcx 48 8b 4d 98 mov -0x68(%rbp),%rcx ff d0 callq *%rax Link: http://lkml.kernel.org/r/2559d7cb-ec60-1200-2362-04fa34fd02bb@fb.com Link: http://lkml.kernel.org/r/20180322121003.4177af15@gandalf.local.homeSigned-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org> Reported-by: NAlexei Starovoitov <ast@fb.com> Acked-by: NDavid Rientjes <rientjes@google.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexei Starovoitov <ast@fb.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrey Ryabinin 提交于
memcg reclaim may alter pgdat->flags based on the state of LRU lists in cgroup and its children. PGDAT_WRITEBACK may force kswapd to sleep congested_wait(), PGDAT_DIRTY may force kswapd to writeback filesystem pages. But the worst here is PGDAT_CONGESTED, since it may force all direct reclaims to stall in wait_iff_congested(). Note that only kswapd have powers to clear any of these bits. This might just never happen if cgroup limits configured that way. So all direct reclaims will stall as long as we have some congested bdi in the system. Leave all pgdat->flags manipulations to kswapd. kswapd scans the whole pgdat, only kswapd can clear pgdat->flags once node is balanced, thus it's reasonable to leave all decisions about node state to kswapd. Why only kswapd? Why not allow to global direct reclaim change these flags? It is because currently only kswapd can clear these flags. I'm less worried about the case when PGDAT_CONGESTED falsely not set, and more worried about the case when it falsely set. If direct reclaimer sets PGDAT_CONGESTED, do we have guarantee that after the congestion problem is sorted out, kswapd will be woken up and clear the flag? It seems like there is no such guarantee. E.g. direct reclaimers may eventually balance pgdat and kswapd simply won't wake up (see wakeup_kswapd()). Moving pgdat->flags manipulation to kswapd, means that cgroup2 recalim now loses its congestion throttling mechanism. Add per-cgroup congestion state and throttle cgroup2 reclaimers if memcg is in congestion state. Currently there is no need in per-cgroup PGDAT_WRITEBACK and PGDAT_DIRTY bits since they alter only kswapd behavior. The problem could be easily demonstrated by creating heavy congestion in one cgroup: echo "+memory" > /sys/fs/cgroup/cgroup.subtree_control mkdir -p /sys/fs/cgroup/congester echo 512M > /sys/fs/cgroup/congester/memory.max echo $$ > /sys/fs/cgroup/congester/cgroup.procs /* generate a lot of diry data on slow HDD */ while true; do dd if=/dev/zero of=/mnt/sdb/zeroes bs=1M count=1024; done & .... while true; do dd if=/dev/zero of=/mnt/sdb/zeroes bs=1M count=1024; done & and some job in another cgroup: mkdir /sys/fs/cgroup/victim echo 128M > /sys/fs/cgroup/victim/memory.max # time cat /dev/sda > /dev/null real 10m15.054s user 0m0.487s sys 1m8.505s According to the tracepoint in wait_iff_congested(), the 'cat' spent 50% of the time sleeping there. With the patch, cat don't waste time anymore: # time cat /dev/sda > /dev/null real 5m32.911s user 0m0.411s sys 0m56.664s [aryabinin@virtuozzo.com: congestion state should be per-node] Link: http://lkml.kernel.org/r/20180406135215.10057-1-aryabinin@virtuozzo.com [ayabinin@virtuozzo.com: make congestion state per-cgroup-per-node instead of just per-cgroup[ Link: http://lkml.kernel.org/r/20180406180254.8970-2-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20180323152029.11084-5-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: NShakeel Butt <shakeelb@google.com> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tejun Heo <tj@kernel.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrey Ryabinin 提交于
We have separate LRU list for each memory cgroup. Memory reclaim iterates over cgroups and calls shrink_inactive_list() every inactive LRU list. Based on the state of a single LRU shrink_inactive_list() may flag the whole node as dirty,congested or under writeback. This is obviously wrong and hurtful. It's especially hurtful when we have possibly small congested cgroup in system. Than *all* direct reclaims waste time by sleeping in wait_iff_congested(). And the more memcgs in the system we have the longer memory allocation stall is, because wait_iff_congested() called on each lru-list scan. Sum reclaim stats across all visited LRUs on node and flag node as dirty, congested or under writeback based on that sum. Also call congestion_wait(), wait_iff_congested() once per pgdat scan, instead of once per lru-list scan. This only fixes the problem for global reclaim case. Per-cgroup reclaim may alter global pgdat flags too, which is wrong. But that is separate issue and will be addressed in the next patch. This change will not have any effect on a systems with all workload concentrated in a single cgroup. [aryabinin@virtuozzo.com: check nr_writeback against all nr_taken, not just file] Link: http://lkml.kernel.org/r/20180406180254.8970-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20180323152029.11084-4-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: NShakeel Butt <shakeelb@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrey Ryabinin 提交于
Only kswapd can have non-zero nr_immediate, and current_may_throttle() is always true for kswapd (PF_LESS_THROTTLE bit is never set) thus it's enough to check stat.nr_immediate only. Link: http://lkml.kernel.org/r/20180315164553.17856-4-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrey Ryabinin 提交于
Update some comments that became stale since transiton from per-zone to per-node reclaim. Link: http://lkml.kernel.org/r/20180315164553.17856-2-aryabinin@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 4月, 2018 3 次提交
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由 David Rientjes 提交于
Kswapd will not wakeup if per-zone watermarks are not failing or if too many previous attempts at background reclaim have failed. This can be true if there is a lot of free memory available. For high- order allocations, kswapd is responsible for waking up kcompactd for background compaction. If the zone is not below its watermarks or reclaim has recently failed (lots of free memory, nothing left to reclaim), kcompactd does not get woken up. When __GFP_DIRECT_RECLAIM is not allowed, allow kcompactd to still be woken up even if kswapd will not reclaim. This allows high-order allocations, such as thp, to still trigger background compaction even when the zone has an abundance of free memory. Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803111659420.209721@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Tetsuo Handa 提交于
Since we no longer use return value of shrink_slab() for normal reclaim, the comment is no longer true. If some do_shrink_slab() call takes unexpectedly long (root cause of stall is currently unknown) when register_shrinker()/unregister_shrinker() is pending, trying to drop caches via /proc/sys/vm/drop_caches could become infinite cond_resched() loop if many mem_cgroup are defined. For safety, let's not pretend forward progress. Link: http://lkml.kernel.org/r/201802202229.GGF26507.LVFtMSOOHFJOQF@I-love.SAKURA.ne.jpSigned-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: NMichal Hocko <mhocko@suse.com> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
When page_mapping() is called and the mapping is dereferenced in page_evicatable() through shrink_active_list(), it is possible for the inode to be truncated and the embedded address space to be freed at the same time. This may lead to the following race. CPU1 CPU2 truncate(inode) shrink_active_list() ... page_evictable(page) truncate_inode_page(mapping, page); delete_from_page_cache(page) spin_lock_irqsave(&mapping->tree_lock, flags); __delete_from_page_cache(page, NULL) page_cache_tree_delete(..) ... mapping = page_mapping(page); page->mapping = NULL; ... spin_unlock_irqrestore(&mapping->tree_lock, flags); page_cache_free_page(mapping, page) put_page(page) if (put_page_testzero(page)) -> false - inode now has no pages and can be freed including embedded address_space mapping_unevictable(mapping) test_bit(AS_UNEVICTABLE, &mapping->flags); - we've dereferenced mapping which is potentially already free. Similar race exists between swap cache freeing and page_evicatable() too. The address_space in inode and swap cache will be freed after a RCU grace period. So the races are fixed via enclosing the page_mapping() and address_space usage in rcu_read_lock/unlock(). Some comments are added in code to make it clear what is protected by the RCU read lock. Link: http://lkml.kernel.org/r/20180212081227.1940-1-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com> Reviewed-by: NJan Kara <jack@suse.cz> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 23 3月, 2018 1 次提交
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由 Andrey Ryabinin 提交于
Commit 726d061f ("mm: vmscan: kick flushers when we encounter dirty pages on the LRU") added flusher invocation to shrink_inactive_list() when many dirty pages on the LRU are encountered. However, shrink_inactive_list() doesn't wake up flushers for legacy cgroup reclaim, so the next commit bbef9384 ("mm: vmscan: remove old flusher wakeup from direct reclaim path") removed the only source of flusher's wake up in legacy mem cgroup reclaim path. This leads to premature OOM if there is too many dirty pages in cgroup: # mkdir /sys/fs/cgroup/memory/test # echo $$ > /sys/fs/cgroup/memory/test/tasks # echo 50M > /sys/fs/cgroup/memory/test/memory.limit_in_bytes # dd if=/dev/zero of=tmp_file bs=1M count=100 Killed dd invoked oom-killer: gfp_mask=0x14000c0(GFP_KERNEL), nodemask=(null), order=0, oom_score_adj=0 Call Trace: dump_stack+0x46/0x65 dump_header+0x6b/0x2ac oom_kill_process+0x21c/0x4a0 out_of_memory+0x2a5/0x4b0 mem_cgroup_out_of_memory+0x3b/0x60 mem_cgroup_oom_synchronize+0x2ed/0x330 pagefault_out_of_memory+0x24/0x54 __do_page_fault+0x521/0x540 page_fault+0x45/0x50 Task in /test killed as a result of limit of /test memory: usage 51200kB, limit 51200kB, failcnt 73 memory+swap: usage 51200kB, limit 9007199254740988kB, failcnt 0 kmem: usage 296kB, limit 9007199254740988kB, failcnt 0 Memory cgroup stats for /test: cache:49632KB rss:1056KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:49500KB writeback:0KB swap:0KB inactive_anon:0KB active_anon:1168KB inactive_file:24760KB active_file:24960KB unevictable:0KB Memory cgroup out of memory: Kill process 3861 (bash) score 88 or sacrifice child Killed process 3876 (dd) total-vm:8484kB, anon-rss:1052kB, file-rss:1720kB, shmem-rss:0kB oom_reaper: reaped process 3876 (dd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB Wake up flushers in legacy cgroup reclaim too. Link: http://lkml.kernel.org/r/20180315164553.17856-1-aryabinin@virtuozzo.com Fixes: bbef9384 ("mm: vmscan: remove old flusher wakeup from direct reclaim path") Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com> Tested-by: NShakeel Butt <shakeelb@google.com> Acked-by: NMichal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 22 2月, 2018 1 次提交
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由 Shakeel Butt 提交于
When a thread mlocks an address space backed either by file pages which are currently not present in memory or swapped out anon pages (not in swapcache), a new page is allocated and added to the local pagevec (lru_add_pvec), I/O is triggered and the thread then sleeps on the page. On I/O completion, the thread can wake on a different CPU, the mlock syscall will then sets the PageMlocked() bit of the page but will not be able to put that page in unevictable LRU as the page is on the pagevec of a different CPU. Even on drain, that page will go to evictable LRU because the PageMlocked() bit is not checked on pagevec drain. The page will eventually go to right LRU on reclaim but the LRU stats will remain skewed for a long time. This patch puts all the pages, even unevictable, to the pagevecs and on the drain, the pages will be added on their LRUs correctly by checking their evictability. This resolves the mlocked pages on pagevec of other CPUs issue because when those pagevecs will be drained, the mlocked file pages will go to unevictable LRU. Also this makes the race with munlock easier to resolve because the pagevec drains happen in LRU lock. However there is still one place which makes a page evictable and does PageLRU check on that page without LRU lock and needs special attention. TestClearPageMlocked() and isolate_lru_page() in clear_page_mlock(). #0: __pagevec_lru_add_fn #1: clear_page_mlock SetPageLRU() if (!TestClearPageMlocked()) return smp_mb() // <--required // inside does PageLRU if (!PageMlocked()) if (isolate_lru_page()) move to evictable LRU putback_lru_page() else move to unevictable LRU In '#1', TestClearPageMlocked() provides full memory barrier semantics and thus the PageLRU check (inside isolate_lru_page) can not be reordered before it. In '#0', without explicit memory barrier, the PageMlocked() check can be reordered before SetPageLRU(). If that happens, '#0' can put a page in unevictable LRU and '#1' might have just cleared the Mlocked bit of that page but fails to isolate as PageLRU fails as '#0' still hasn't set PageLRU bit of that page. That page will be stranded on the unevictable LRU. There is one (good) side effect though. Without this patch, the pages allocated for System V shared memory segment are added to evictable LRUs even after shmctl(SHM_LOCK) on that segment. This patch will correctly put such pages to unevictable LRU. Link: http://lkml.kernel.org/r/20171121211241.18877-1-shakeelb@google.comSigned-off-by: NShakeel Butt <shakeelb@google.com> Acked-by: NVlastimil Babka <vbabka@suse.cz> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Shaohua Li <shli@fb.com> Cc: Jan Kara <jack@suse.cz> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 2月, 2018 1 次提交
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由 Mike Rapoport 提交于
Link: http://lkml.kernel.org/r/1516700871-22279-4-git-send-email-rppt@linux.vnet.ibm.comSigned-off-by: NMike Rapoport <rppt@linux.vnet.ibm.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 01 2月, 2018 3 次提交
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由 Mel Gorman 提交于
Minchan Kim asked the following question -- what locks protects address_space destroying when race happens between inode trauncation and __isolate_lru_page? Jan Kara clarified by describing the race as follows CPU1 CPU2 truncate(inode) __isolate_lru_page() ... truncate_inode_page(mapping, page); delete_from_page_cache(page) spin_lock_irqsave(&mapping->tree_lock, flags); __delete_from_page_cache(page, NULL) page_cache_tree_delete(..) ... mapping = page_mapping(page); page->mapping = NULL; ... spin_unlock_irqrestore(&mapping->tree_lock, flags); page_cache_free_page(mapping, page) put_page(page) if (put_page_testzero(page)) -> false - inode now has no pages and can be freed including embedded address_space if (mapping && !mapping->a_ops->migratepage) - we've dereferenced mapping which is potentially already free. The race is theoretically possible but unlikely. Before the delete_from_page_cache, truncate_cleanup_page is called so the page is likely to be !PageDirty or PageWriteback which gets skipped by the only caller that checks the mappping in __isolate_lru_page. Even if the race occurs, a substantial amount of work has to happen during a tiny window with no preemption but it could potentially be done using a virtual machine to artifically slow one CPU or halt it during the critical window. This patch should eliminate the race with truncation by try-locking the page before derefencing mapping and aborting if the lock was not acquired. There was a suggestion from Huang Ying to use RCU as a side-effect to prevent mapping being freed. However, I do not like the solution as it's an unconventional means of preserving a mapping and it's not a context where rcu_read_lock is obviously protecting rcu data. Link: http://lkml.kernel.org/r/20180104102512.2qos3h5vqzeisrek@techsingularity.net Fixes: c8244935 ("mm: compaction: make isolate_lru_page() filter-aware again") Signed-off-by: NMel Gorman <mgorman@techsingularity.net> Acked-by: NMinchan Kim <minchan@kernel.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Jan Kara <jack@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Jan Kara 提交于
Remove unused function pgdat_reclaimable_pages() and node_page_state_snapshot() which becomes unused as well. Link: http://lkml.kernel.org/r/20171122094416.26019-1-jack@suse.czSigned-off-by: NJan Kara <jack@suse.cz> Acked-by: NMichal Hocko <mhocko@suse.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Minchan Kim 提交于
Shakeel Butt reported he has observed in production systems that the job loader gets stuck for 10s of seconds while doing a mount operation. It turns out that it was stuck in register_shrinker() because some unrelated job was under memory pressure and was spending time in shrink_slab(). Machines have a lot of shrinkers registered and jobs under memory pressure have to traverse all of those memcg-aware shrinkers and affect unrelated jobs which want to register their own shrinkers. To solve the issue, this patch simply bails out slab shrinking if it is found that someone wants to register a shrinker in parallel. A downside is it could cause unfair shrinking between shrinkers. However, it should be rare and we can add compilcated logic if we find it's not enough. [akpm@linux-foundation.org: tweak code comment] Link: http://lkml.kernel.org/r/20171115005602.GB23810@bbox Link: http://lkml.kernel.org/r/1511481899-20335-1-git-send-email-minchan@kernel.orgSigned-off-by: NMinchan Kim <minchan@kernel.org> Signed-off-by: NShakeel Butt <shakeelb@google.com> Reported-by: NShakeel Butt <shakeelb@google.com> Tested-by: NShakeel Butt <shakeelb@google.com> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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