user/sven/linux.git/include/linux/swap.h, branch v3.2.78

SHM_UNLOCK: fix Unevictable pages stranded after swap

2012-01-26T00:13:59Z

commit 245132643e1cfcd145bbc86a716c1818371fcb93 upstream. Commit cc39c6a9bbde ("mm: account skipped entries to avoid looping in find_get_pages") correctly fixed an infinite loop; but left a problem that find_get_pages() on shmem would return 0 (appearing to callers to mean end of tree) when it meets a run of nr_pages swap entries. The only uses of find_get_pages() on shmem are via pagevec_lookup(), called from invalidate_mapping_pages(), and from shmctl SHM_UNLOCK's scan_mapping_unevictable_pages(). The first is already commented, and not worth worrying about; but the second can leave pages on the Unevictable list after an unusual sequence of swapping and locking. Fix that by using shmem_find_get_pages_and_swap() (then ignoring the swap) instead of pagevec_lookup(). But I don't want to contaminate vmscan.c with shmem internals, nor shmem.c with LRU locking. So move scan_mapping_unevictable_pages() into shmem.c, renaming it shmem_unlock_mapping(); and rename check_move_unevictable_page() to check_move_unevictable_pages(), looping down an array of pages, oftentimes under the same lock. Leave out the "rotate unevictable list" block: that's a leftover from when this was used for /proc/sys/vm/scan_unevictable_pages, whose flawed handling involved looking at pages at tail of LRU. Was there significance to the sequence first ClearPageUnevictable, then test page_evictable, then SetPageUnevictable here? I think not, we're under LRU lock, and have no barriers between those. Signed-off-by: Hugh Dickins Reviewed-by: KOSAKI Motohiro Cc: Minchan Kim Cc: Rik van Riel Cc: Shaohua Li Cc: Eric Dumazet Cc: Johannes Weiner Cc: Michel Lespinasse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: change isolate mode from #define to bitwise type

2011-11-01T00:30:44Z

Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by: Minchan Kim Cc: Johannes Weiner Cc: KAMEZAWA Hiroyuki Cc: KOSAKI Motohiro Cc: Mel Gorman Cc: Rik van Riel Cc: Michal Hocko Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: Revert "memcg: add memory.vmscan_stat"

2011-09-15T01:09:38Z

Revert the post-3.0 commit 82f9d486e59f5 ("memcg: add memory.vmscan_stat"). The implementation of per-memcg reclaim statistics violates how memcg hierarchies usually behave: hierarchically. The reclaim statistics are accounted to child memcgs and the parent hitting the limit, but not to hierarchy levels in between. Usually, hierarchical statistics are perfectly recursive, with each level representing the sum of itself and all its children. Since this exports statistics to userspace, this may lead to confusion and problems with changing things after the release, so revert it now, we can try again later. Signed-off-by: Johannes Weiner Acked-by: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura Cc: Michal Hocko Cc: Ying Han Cc: Balbir Singh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

atomic: use

2011-07-26T23:49:47Z

This allows us to move duplicated code in (atomic_inc_not_zero() for now) to Signed-off-by: Arun Sharma Reviewed-by: Eric Dumazet Cc: Ingo Molnar Cc: David Miller Cc: Eric Dumazet Acked-by: Mike Frysinger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: add memory.vmscan_stat

2011-07-26T23:49:42Z

The commit log of 0ae5e89c60c9 ("memcg: count the soft_limit reclaim in...") says it adds scanning stats to memory.stat file. But it doesn't because we considered we needed to make a concensus for such new APIs. This patch is a trial to add memory.scan_stat. This shows - the number of scanned pages(total, anon, file) - the number of rotated pages(total, anon, file) - the number of freed pages(total, anon, file) - the number of elaplsed time (including sleep/pause time) for both of direct/soft reclaim. The biggest difference with oringinal Ying's one is that this file can be reset by some write, as # echo 0 ...../memory.scan_stat Example of output is here. This is a result after make -j 6 kernel under 300M limit. [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat scanned_pages_by_limit 9471864 scanned_anon_pages_by_limit 6640629 scanned_file_pages_by_limit 2831235 rotated_pages_by_limit 4243974 rotated_anon_pages_by_limit 3971968 rotated_file_pages_by_limit 272006 freed_pages_by_limit 2318492 freed_anon_pages_by_limit 962052 freed_file_pages_by_limit 1356440 elapsed_ns_by_limit 351386416101 scanned_pages_by_system 0 scanned_anon_pages_by_system 0 scanned_file_pages_by_system 0 rotated_pages_by_system 0 rotated_anon_pages_by_system 0 rotated_file_pages_by_system 0 freed_pages_by_system 0 freed_anon_pages_by_system 0 freed_file_pages_by_system 0 elapsed_ns_by_system 0 scanned_pages_by_limit_under_hierarchy 9471864 scanned_anon_pages_by_limit_under_hierarchy 6640629 scanned_file_pages_by_limit_under_hierarchy 2831235 rotated_pages_by_limit_under_hierarchy 4243974 rotated_anon_pages_by_limit_under_hierarchy 3971968 rotated_file_pages_by_limit_under_hierarchy 272006 freed_pages_by_limit_under_hierarchy 2318492 freed_anon_pages_by_limit_under_hierarchy 962052 freed_file_pages_by_limit_under_hierarchy 1356440 elapsed_ns_by_limit_under_hierarchy 351386416101 scanned_pages_by_system_under_hierarchy 0 scanned_anon_pages_by_system_under_hierarchy 0 scanned_file_pages_by_system_under_hierarchy 0 rotated_pages_by_system_under_hierarchy 0 rotated_anon_pages_by_system_under_hierarchy 0 rotated_file_pages_by_system_under_hierarchy 0 freed_pages_by_system_under_hierarchy 0 freed_anon_pages_by_system_under_hierarchy 0 freed_file_pages_by_system_under_hierarchy 0 elapsed_ns_by_system_under_hierarchy 0 total_xxxx is for hierarchy management. This will be useful for further memcg developments and need to be developped before we do some complicated rework on LRU/softlimit management. This patch adds a new struct memcg_scanrecord into scan_control struct. sc->nr_scanned at el is not designed for exporting information. For example, nr_scanned is reset frequentrly and incremented +2 at scanning mapped pages. To avoid complexity, I added a new param in scan_control which is for exporting scanning score. Signed-off-by: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura Cc: Michal Hocko Cc: Ying Han Cc: Andrew Bresticker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: export memory cgroup's swappiness with mem_cgroup_swappiness()

2011-07-26T23:49:42Z

Each memory cgroup has a 'swappiness' value which can be accessed by get_swappiness(memcg). The major user is try_to_free_mem_cgroup_pages() and swappiness is passed by argument. It's propagated by scan_control. get_swappiness() is a static function but some planned updates will need to get swappiness from files other than memcontrol.c This patch exports get_swappiness() as mem_cgroup_swappiness(). With this, we can remove the argument of swapiness from try_to_free... and drop swappiness from scan_control. only memcg uses it. Signed-off-by: KAMEZAWA Hiroyuki Cc: Daisuke Nishimura Cc: Balbir Singh Cc: Michal Hocko Cc: Ying Han Cc: Shaohua Li Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move shmem prototypes to shmem_fs.h

2011-06-28T01:00:12Z

Before adding any more global entry points into shmem.c, gather such prototypes into shmem_fs.h. Remove mm's own declarations from swap.h, but for now leave the ones in mm.h: because shmem_file_setup() and shmem_zero_setup() are called from various places, and we should not force other subsystems to update immediately. Signed-off-by: Hugh Dickins Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmscan,memcg: memcg aware swap token

2011-06-16T03:03:59Z

Currently, memcg reclaim can disable swap token even if the swap token mm doesn't belong in its memory cgroup. It's slightly risky. If an admin creates very small mem-cgroup and silly guy runs contentious heavy memory pressure workload, every tasks are going to lose swap token and then system may become unresponsive. That's bad. This patch adds 'memcg' parameter into disable_swap_token(). and if the parameter doesn't match swap token, VM doesn't disable it. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memcg: count the soft_limit reclaim in global background reclaim

2011-05-27T00:12:35Z

The global kswapd scans per-zone LRU and reclaims pages regardless of the cgroup. It breaks memory isolation since one cgroup can end up reclaiming pages from another cgroup. Instead we should rely on memcg-aware target reclaim including per-memcg kswapd and soft_limit hierarchical reclaim under memory pressure. In the global background reclaim, we do soft reclaim before scanning the per-zone LRU. However, the return value is ignored. This patch is the first step to skip shrink_zone() if soft_limit reclaim does enough work. This is part of the effort which tries to reduce reclaiming pages in global LRU in memcg. The per-memcg background reclaim patchset further enhances the per-cgroup targetting reclaim, which I should have V4 posted shortly. Try running multiple memory intensive workloads within seperate memcgs. Watch the counters of soft_steal in memory.stat. $ cat /dev/cgroup/A/memory.stat | grep 'soft' soft_steal 240000 soft_scan 240000 total_soft_steal 240000 total_soft_scan 240000 This patch: In the global background reclaim, we do soft reclaim before scanning the per-zone LRU. However, the return value is ignored. We would like to skip shrink_zone() if soft_limit reclaim does enough work. Also, we need to make the memory pressure balanced across per-memcg zones, like the logic vm-core. This patch is the first step where we start with counting the nr_scanned and nr_reclaimed from soft_limit reclaim into the global scan_control. Signed-off-by: Ying Han Cc: KOSAKI Motohiro Cc: Minchan Kim Cc: Rik van Riel Cc: Mel Gorman Cc: KAMEZAWA Hiroyuki Cc: Balbir Singh Acked-by: Daisuke Nishimura Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block

2011-03-24T17:16:26Z

* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}