To Mel ====== Mel, I have identified the overly aggressive behavior you noticed to be a bug in the at-least-one-pass patch, that would ask the shrinkers to scan the full batch even when total_scan < batch. They would do their best for it, and eventually succeed. I also went further, and made that the behavior of direct reclaim only - The only case that really matter for memcg, and one in which we could argue that we are more or less desperate for small squeezes in memory. Thank you very much for spotting this. Running postmark on the final result (at least on my 2-node box) show something a lot saner. We are still stealing more inodes than before, but by a factor of around 15 %. Since the correct balance is somewhat heuristic anyway - I personally think this is acceptable. But I am waiting to hear from you on this matter. Meanwhile, I am investigating further to try to pinpoint where exactly this comes from. It might either be because of the new node-aware behavior, or because of the increased calculation precision in the first patch. In particular, I haven't done anything about your comment regarding MAX_NODES array. After the memcg patches are applying, fixing this is a lot easier, because memcg already departs from a static MAX_NODES array to a dynamic one. I wanted, however, to keep the noise introduction down in something that I expect to be merged soon. I would suggest merging a patch that fixes that on top of the series, instead of the middle, if you really think it matters. I, of course, commit to doing this in that case. The work ======== Hi, This patchset implements targeted shrinking for memcg when kmem limits are present. So far, we've been accounting kernel objects but failing allocations when short of memory. This is because our only option would be to call the global shrinker, depleting objects from all caches and breaking isolation. The main idea is to associate per-memcg lists with each of the LRUs. The main LRU still provides a single entry point and when adding or removing an element from the LRU, we use the page information to figure out which memcg it belongs to and relay it to the right list. Base work: ========== Please note that this builds upon the recent work from Dave Chinner that sanitizes the LRU shrinking API and make the shrinkers node aware. Node awareness is not *strictly* needed for my work, but I still perceive it as an advantage. The API unification is a major need, and I build upon it heavily. That allows us to manipulate the LRUs without knowledge of the underlying objects with ease. This time, I am including that work here as a baseline. Main changes from *v4: * Fixed a bug in user-generated memcg pressure * Fixed overly-agressive slab shrinker behavior spotted by Mel Gorman * Various other fixes and comments by Mel Gorman Main changes from *v3: * Merged suggestions from mailing list. * Removed the memcg-walking code from LRU. vmscan now drives all the hierarchy decisions, which makes more sense * lazily free the old memcg arrays (needs now to be saved in struct lru). Since we need to call synchronize_rcu, calling it for every LRU can become expensive * Moved the dead memcg shrinker to vmpressure. Already independently sent to linux-mm for review. * Changed locking convention for LRU_RETRY. It now needs to return locked, which silents warnings about possible lock unbalance (although previous code was correct) Main changes from *v2: * shrink dead memcgs when global pressure kicks in. Uses the new lru API. * bugfixes and comments from the mailing list. * proper hierarchy-aware walk in shrink_slab. Main changes from *v1: * merged comments from the mailing list * reworked lru-memcg API * effective proportional shrinking * sanitized locking on the memcg side * bill user memory first when kmem == umem * various bugfixes Dave Chinner (17): dcache: convert dentry_stat.nr_unused to per-cpu counters dentry: move to per-sb LRU locks dcache: remove dentries from LRU before putting on dispose list mm: new shrinker API shrinker: convert superblock shrinkers to new API list: add a new LRU list type inode: convert inode lru list to generic lru list code. dcache: convert to use new lru list infrastructure list_lru: per-node list infrastructure shrinker: add node awareness fs: convert inode and dentry shrinking to be node aware xfs: convert buftarg LRU to generic code xfs: convert dquot cache lru to list_lru fs: convert fs shrinkers to new scan/count API drivers: convert shrinkers to new count/scan API shrinker: convert remaining shrinkers to count/scan API shrinker: Kill old ->shrink API. Glauber Costa (14): super: fix calculation of shrinkable objects for small numbers vmscan: take at least one pass with shrinkers hugepage: convert huge zero page shrinker to new shrinker API vmscan: also shrink slab in memcg pressure memcg,list_lru: duplicate LRUs upon kmemcg creation lru: add an element to a memcg list list_lru: per-memcg walks memcg: per-memcg kmem shrinking memcg: scan cache objects hierarchically super: targeted memcg reclaim memcg: move initialization to memcg creation vmpressure: in-kernel notifications memcg: reap dead memcgs upon global memory pressure. memcg: debugging facility to access dangling memcgs Documentation/cgroups/memory.txt | 16 + arch/x86/kvm/mmu.c | 28 +- drivers/gpu/drm/i915/i915_dma.c | 4 +- drivers/gpu/drm/i915/i915_gem.c | 67 +++- drivers/gpu/drm/ttm/ttm_page_alloc.c | 48 ++- drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 55 ++- drivers/md/bcache/btree.c | 30 +- drivers/md/bcache/sysfs.c | 2 +- drivers/md/dm-bufio.c | 65 ++-- drivers/staging/android/ashmem.c | 46 ++- drivers/staging/android/lowmemorykiller.c | 40 +- drivers/staging/zcache/zcache-main.c | 29 +- fs/dcache.c | 234 +++++++----- fs/drop_caches.c | 1 + fs/ext4/extents_status.c | 30 +- fs/gfs2/glock.c | 30 +- fs/gfs2/main.c | 3 +- fs/gfs2/quota.c | 14 +- fs/gfs2/quota.h | 4 +- fs/inode.c | 175 ++++----- fs/internal.h | 5 + fs/mbcache.c | 53 +-- fs/nfs/dir.c | 20 +- fs/nfs/internal.h | 4 +- fs/nfs/super.c | 3 +- fs/nfsd/nfscache.c | 31 +- fs/quota/dquot.c | 39 +- fs/super.c | 107 ++++-- fs/ubifs/shrinker.c | 20 +- fs/ubifs/super.c | 3 +- fs/ubifs/ubifs.h | 3 +- fs/xfs/xfs_buf.c | 169 ++++---- fs/xfs/xfs_buf.h | 5 +- fs/xfs/xfs_dquot.c | 7 +- fs/xfs/xfs_icache.c | 4 +- fs/xfs/xfs_icache.h | 2 +- fs/xfs/xfs_qm.c | 275 ++++++------- fs/xfs/xfs_qm.h | 4 +- fs/xfs/xfs_super.c | 12 +- include/linux/dcache.h | 4 + include/linux/fs.h | 25 +- include/linux/list_lru.h | 134 +++++++ include/linux/memcontrol.h | 45 +++ include/linux/shrinker.h | 44 ++- include/linux/swap.h | 2 + include/linux/vmpressure.h | 6 + include/trace/events/vmscan.h | 4 +- init/Kconfig | 17 + lib/Makefile | 2 +- lib/list_lru.c | 430 +++++++++++++++++++++ mm/huge_memory.c | 17 +- mm/memcontrol.c | 614 +++++++++++++++++++++++++++--- mm/memory-failure.c | 2 + mm/slab_common.c | 1 - mm/vmpressure.c | 52 ++- mm/vmscan.c | 334 +++++++++++----- net/sunrpc/auth.c | 45 ++- 57 files changed, 2537 insertions(+), 928 deletions(-) create mode 100644 include/linux/list_lru.h create mode 100644 lib/list_lru.c -- 1.8.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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