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* trylock_super(): replacement for grab_super_passive()Konstantin Khlebnikov2015-02-221-22/+18
| | | | | | | | | | | | | | | | | | | | | | | | | I've noticed significant locking contention in memory reclaimer around sb_lock inside grab_super_passive(). Grab_super_passive() is called from two places: in icache/dcache shrinkers (function super_cache_scan) and from writeback (function __writeback_inodes_wb). Both are required for progress in memory allocator. Grab_super_passive() acquires sb_lock to increment sb->s_count and check sb->s_instances. It seems sb->s_umount locked for read is enough here: super-block deactivation always runs under sb->s_umount locked for write. Protecting super-block itself isn't a problem: in super_cache_scan() sb is protected by shrinker_rwsem: it cannot be freed if its slab shrinkers are still active. Inside writeback super-block comes from inode from bdi writeback list under wb->list_lock. This patch removes locking sb_lock and checks s_instances under s_umount: generic_shutdown_super() unlinks it under sb->s_umount locked for write. New variant is called trylock_super() and since it only locks semaphore, callers must call up_read(&sb->s_umount) instead of drop_super(sb) when they're done. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2015-02-171-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc VFS updates from Al Viro: "This cycle a lot of stuff sits on topical branches, so I'll be sending more or less one pull request per branch. This is the first pile; more to follow in a few. In this one are several misc commits from early in the cycle (before I went for separate branches), plus the rework of mntput/dput ordering on umount, switching to use of fs_pin instead of convoluted games in namespace_unlock()" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch the IO-triggering parts of umount to fs_pin new fs_pin killing logics allow attaching fs_pin to a group not associated with some superblock get rid of the second argument of acct_kill() take count and rcu_head out of fs_pin dcache: let the dentry count go down to zero without taking d_lock pull bumping refcount into ->kill() kill pin_put() mode_t whack-a-mole: chelsio file->f_path.dentry is pinned down for as long as the file is open... get rid of lustre_dump_dentry() gut proc_register() a bit kill d_validate() ncpfs: get rid of d_validate() nonsense selinuxfs: don't open-code d_genocide()
| * allow attaching fs_pin to a group not associated with some superblockAl Viro2015-01-251-2/+2
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'akpm' (patches from Andrew)Linus Torvalds2015-02-121-19/+28
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge third set of updates from Andrew Morton: - the rest of MM [ This includes getting rid of the numa hinting bits, in favor of just generic protnone logic. Yay. - Linus ] - core kernel - procfs - some of lib/ (lots of lib/ material this time) * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (104 commits) lib/lcm.c: replace include lib/percpu_ida.c: remove redundant includes lib/strncpy_from_user.c: replace module.h include lib/stmp_device.c: replace module.h include lib/sort.c: move include inside #if 0 lib/show_mem.c: remove redundant include lib/radix-tree.c: change to simpler include lib/plist.c: remove redundant include lib/nlattr.c: remove redundant include lib/kobject_uevent.c: remove redundant include lib/llist.c: remove redundant include lib/md5.c: simplify include lib/list_sort.c: rearrange includes lib/genalloc.c: remove redundant include lib/idr.c: remove redundant include lib/halfmd4.c: simplify includes lib/dynamic_queue_limits.c: simplify includes lib/sort.c: use simpler includes lib/interval_tree.c: simplify includes hexdump: make it return number of bytes placed in buffer ...
| * | fs: shrinker: always scan at least one object of each typeVladimir Davydov2015-02-121-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In super_cache_scan() we divide the number of objects of particular type by the total number of objects in order to distribute pressure among As a result, in some corner cases we can get nr_to_scan=0 even if there are some objects to reclaim, e.g. dentries=1, inodes=1, fs_objects=1, nr_to_scan=1/3=0. This is unacceptable for per memcg kmem accounting, because this means that some objects may never get reclaimed after memcg death, preventing it from being freed. This patch therefore assures that super_cache_scan() will scan at least one object of each type if any. [akpm@linux-foundation.org: add comment] Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | fs: make shrinker memcg awareVladimir Davydov2015-02-121-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, to make any list_lru-based shrinker memcg aware we should only initialize its list_lru as memcg aware. Let's do it for the general FS shrinker (super_block::s_shrink). There are other FS-specific shrinkers that use list_lru for storing objects, such as XFS and GFS2 dquot cache shrinkers, but since they reclaim objects that are shared among different cgroups, there is no point making them memcg aware. It's a big question whether we should account them to memcg at all. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | list_lru: organize all list_lrus to listVladimir Davydov2015-02-121-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To make list_lru memcg aware, we need all list_lrus to be kept on a list protected by a mutex, so that we could sleep while walking over the list. Therefore after this change list_lru_destroy may sleep. Fortunately, there is only one user that calls it from an atomic context - it's put_super - and we can easily fix it by calling list_lru_destroy before put_super in destroy_locked_super - anyway we don't longer need lrus by that time. Another point that should be noted is that list_lru_destroy is allowed to be called on an uninitialized zeroed-out object, in which case it is a no-op. Before this patch this was guaranteed by kfree, but now we need an explicit check there. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | fs: consolidate {nr,free}_cached_objects args in shrink_controlVladimir Davydov2015-02-121-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We are going to make FS shrinkers memcg-aware. To achieve that, we will have to pass the memcg to scan to the nr_cached_objects and free_cached_objects VFS methods, which currently take only the NUMA node to scan. Since the shrink_control structure already holds the node, and the memcg to scan will be added to it when we introduce memcg-aware vmscan, let us consolidate the methods' arguments in this structure to keep things clean. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| * | list_lru: introduce list_lru_shrink_{count,walk}Vladimir Davydov2015-02-121-13/+11
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kmem accounting of memcg is unusable now, because it lacks slab shrinker support. That means when we hit the limit we will get ENOMEM w/o any chance to recover. What we should do then is to call shrink_slab, which would reclaim old inode/dentry caches from this cgroup. This is what this patch set is intended to do. Basically, it does two things. First, it introduces the notion of per-memcg slab shrinker. A shrinker that wants to reclaim objects per cgroup should mark itself as SHRINKER_MEMCG_AWARE. Then it will be passed the memory cgroup to scan from in shrink_control->memcg. For such shrinkers shrink_slab iterates over the whole cgroup subtree under the target cgroup and calls the shrinker for each kmem-active memory cgroup. Secondly, this patch set makes the list_lru structure per-memcg. It's done transparently to list_lru users - everything they have to do is to tell list_lru_init that they want memcg-aware list_lru. Then the list_lru will automatically distribute objects among per-memcg lists basing on which cgroup the object is accounted to. This way to make FS shrinkers (icache, dcache) memcg-aware we only need to make them use memcg-aware list_lru, and this is what this patch set does. As before, this patch set only enables per-memcg kmem reclaim when the pressure goes from memory.limit, not from memory.kmem.limit. Handling memory.kmem.limit is going to be tricky due to GFP_NOFS allocations, and it is still unclear whether we will have this knob in the unified hierarchy. This patch (of 9): NUMA aware slab shrinkers use the list_lru structure to distribute objects coming from different NUMA nodes to different lists. Whenever such a shrinker needs to count or scan objects from a particular node, it issues commands like this: count = list_lru_count_node(lru, sc->nid); freed = list_lru_walk_node(lru, sc->nid, isolate_func, isolate_arg, &sc->nr_to_scan); where sc is an instance of the shrink_control structure passed to it from vmscan. To simplify this, let's add special list_lru functions to be used by shrinkers, list_lru_shrink_count() and list_lru_shrink_walk(), which consolidate the nid and nr_to_scan arguments in the shrink_control structure. This will also allow us to avoid patching shrinkers that use list_lru when we make shrink_slab() per-memcg - all we will have to do is extend the shrink_control structure to include the target memcg and make list_lru_shrink_{count,walk} handle this appropriately. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Make super_blocks and sb_lock staticAl Viro2015-02-021-2/+2
| | | | | | | | | | | | | | | | The only user outside of fs/super.c is gone now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
* | fs: remove default_backing_dev_infoChristoph Hellwig2015-01-201-6/+2
|/ | | | | | | | | | | | | | | | | | Now that default_backing_dev_info is not used for writeback purposes we can git rid of it easily: - instead of using it's name for tracing unregistered bdi we just use "unknown" - btrfs and ceph can just assign the default read ahead window themselves like several other filesystems already do. - we can assign noop_backing_dev_info as the default one in alloc_super. All filesystems already either assigned their own or noop_backing_dev_info. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2014-10-131-0/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "The big thing in this pile is Eric's unmount-on-rmdir series; we finally have everything we need for that. The final piece of prereqs is delayed mntput() - now filesystem shutdown always happens on shallow stack. Other than that, we have several new primitives for iov_iter (Matt Wilcox, culled from his XIP-related series) pushing the conversion to ->read_iter()/ ->write_iter() a bit more, a bunch of fs/dcache.c cleanups and fixes (including the external name refcounting, which gives consistent behaviour of d_move() wrt procfs symlinks for long and short names alike) and assorted cleanups and fixes all over the place. This is just the first pile; there's a lot of stuff from various people that ought to go in this window. Starting with unionmount/overlayfs mess... ;-/" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (60 commits) fs/file_table.c: Update alloc_file() comment vfs: Deduplicate code shared by xattr system calls operating on paths reiserfs: remove pointless forward declaration of struct nameidata don't need that forward declaration of struct nameidata in dcache.h anymore take dname_external() into fs/dcache.c let path_init() failures treated the same way as subsequent link_path_walk() fix misuses of f_count() in ppp and netlink ncpfs: use list_for_each_entry() for d_subdirs walk vfs: move getname() from callers to do_mount() gfs2_atomic_open(): skip lookups on hashed dentry [infiniband] remove pointless assignments gadgetfs: saner API for gadgetfs_create_file() f_fs: saner API for ffs_sb_create_file() jfs: don't hash direct inode [s390] remove pointless assignment of ->f_op in vmlogrdr ->open() ecryptfs: ->f_op is never NULL android: ->f_op is never NULL nouveau: __iomem misannotations missing annotation in fs/file.c fs: namespace: suppress 'may be used uninitialized' warnings ...
| * fs: Fix theoretical division by 0 in super_cache_scan().Tetsuo Handa2014-10-091-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | total_objects could be 0 and is used as a denom. While total_objects is a "long", total_objects == 0 unlikely happens for 3.12 and later kernels because 32-bit architectures would not be able to hold (1 << 32) objects. However, total_objects == 0 may happen for kernels between 3.1 and 3.11 because total_objects in prune_super() was an "int" and (e.g.) x86_64 architecture might be able to hold (1 << 32) objects. Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: stable <stable@kernel.org> # 3.1+ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | percpu_counter: add @gfp to percpu_counter_init()Tejun Heo2014-09-081-1/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | Percpu allocator now supports allocation mask. Add @gfp to percpu_counter_init() so that !GFP_KERNEL allocation masks can be used with percpu_counters too. We could have left percpu_counter_init() alone and added percpu_counter_init_gfp(); however, the number of users isn't that high and introducing _gfp variants to all percpu data structures would be quite ugly, so let's just do the conversion. This is the one with the most users. Other percpu data structures are a lot easier to convert. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: x86@kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org>
* Merge branch 'for_linus' of ↵Linus Torvalds2014-08-131-1/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull quota, reiserfs, UDF updates from Jan Kara: "Scalability improvements for quota, a few reiserfs fixes, and couple of misc cleanups (udf, ext2)" * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: reiserfs: Fix use after free in journal teardown reiserfs: fix corruption introduced by balance_leaf refactor udf: avoid redundant memcpy when writing data in ICB fs/udf: re-use hex_asc_upper_{hi,lo} macros fs/quota: kernel-doc warning fixes udf: use linux/uaccess.h fs/ext2/super.c: Drop memory allocation cast quota: remove dqptr_sem quota: simplify remove_inode_dquot_ref() quota: avoid unnecessary dqget()/dqput() calls quota: protect Q_GETFMT by dqonoff_mutex
| * quota: remove dqptr_semNiu Yawei2014-07-151-1/+0
| | | | | | | | | | | | | | | | | | | | Remove dqptr_sem to make quota code scalable: Remove the dqptr_sem, accessing inode->i_dquot now protected by dquot_srcu, and changing inode->i_dquot is now serialized by dq_data_lock. Signed-off-by: Lai Siyao <lai.siyao@intel.com> Signed-off-by: Niu Yawei <yawei.niu@intel.com> Signed-off-by: Jan Kara <jack@suse.cz>
* | make fs/{namespace,super}.c forget about acct.hAl Viro2014-08-071-2/+1
| | | | | | | | | | | | | | These externs belong in fs/internal.h. Rename (they are not acct-specific anymore) and move them over there. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | drop ->s_umount around acct_auto_close()Al Viro2014-08-071-4/+14
| | | | | | | | | | | | | | | | | | | | just repeat the frozen check after regaining it, and check that sb is still alive. If several threads hit acct_auto_close() at the same time, acct_auto_close() will survive that just fine. And we really don't want to play with writes and closing the file with ->s_umount held exclusive - it's a deadlock country. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | acct: get rid of acct_listAl Viro2014-08-071-1/+1
|/ | | | | | | | Put these suckers on per-vfsmount and per-superblock lists instead. Note: right now it's still acct_lock for everything, but that's going to change. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/superblock: avoid locking counting inodes and dentries before reclaiming themTim Chen2014-06-041-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We remove the call to grab_super_passive in call to super_cache_count. This becomes a scalability bottleneck as multiple threads are trying to do memory reclamation, e.g. when we are doing large amount of file read and page cache is under pressure. The cached objects quickly got reclaimed down to 0 and we are aborting the cache_scan() reclaim. But counting creates a log jam acquiring the sb_lock. We are holding the shrinker_rwsem which ensures the safety of call to list_lru_count_node() and s_op->nr_cached_objects. The shrinker is unregistered now before ->kill_sb() so the operation is safe when we are doing unmount. The impact will depend heavily on the machine and the workload but for a small machine using postmark tuned to use 4xRAM size the results were 3.15.0-rc5 3.15.0-rc5 vanilla shrinker-v1r1 Ops/sec Transactions 21.00 ( 0.00%) 24.00 ( 14.29%) Ops/sec FilesCreate 39.00 ( 0.00%) 44.00 ( 12.82%) Ops/sec CreateTransact 10.00 ( 0.00%) 12.00 ( 20.00%) Ops/sec FilesDeleted 6202.00 ( 0.00%) 6202.00 ( 0.00%) Ops/sec DeleteTransact 11.00 ( 0.00%) 12.00 ( 9.09%) Ops/sec DataRead/MB 25.97 ( 0.00%) 29.10 ( 12.05%) Ops/sec DataWrite/MB 49.99 ( 0.00%) 56.02 ( 12.06%) ffsb running in a configuration that is meant to simulate a mail server showed 3.15.0-rc5 3.15.0-rc5 vanilla shrinker-v1r1 Ops/sec readall 9402.63 ( 0.00%) 9567.97 ( 1.76%) Ops/sec create 4695.45 ( 0.00%) 4735.00 ( 0.84%) Ops/sec delete 173.72 ( 0.00%) 179.83 ( 3.52%) Ops/sec Transactions 14271.80 ( 0.00%) 14482.81 ( 1.48%) Ops/sec Read 37.00 ( 0.00%) 37.60 ( 1.62%) Ops/sec Write 18.20 ( 0.00%) 18.30 ( 0.55%) Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Chinner <david@fromorbit.com> Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Jan Kara <jack@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs/superblock: unregister sb shrinker before ->kill_sb()Dave Chinner2014-06-041-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This series is aimed at regressions noticed during reclaim activity. The first two patches are shrinker patches that were posted ages ago but never merged for reasons that are unclear to me. I'm posting them again to see if there was a reason they were dropped or if they just got lost. Dave? Time? The last patch adjusts proportional reclaim. Yuanhan Liu, can you retest the vm scalability test cases on a larger machine? Hugh, does this work for you on the memcg test cases? Based on ext4, I get the following results but unfortunately my larger test machines are all unavailable so this is based on a relatively small machine. postmark 3.15.0-rc5 3.15.0-rc5 vanilla proportion-v1r4 Ops/sec Transactions 21.00 ( 0.00%) 25.00 ( 19.05%) Ops/sec FilesCreate 39.00 ( 0.00%) 45.00 ( 15.38%) Ops/sec CreateTransact 10.00 ( 0.00%) 12.00 ( 20.00%) Ops/sec FilesDeleted 6202.00 ( 0.00%) 6202.00 ( 0.00%) Ops/sec DeleteTransact 11.00 ( 0.00%) 12.00 ( 9.09%) Ops/sec DataRead/MB 25.97 ( 0.00%) 30.02 ( 15.59%) Ops/sec DataWrite/MB 49.99 ( 0.00%) 57.78 ( 15.58%) ffsb (mail server simulator) 3.15.0-rc5 3.15.0-rc5 vanilla proportion-v1r4 Ops/sec readall 9402.63 ( 0.00%) 9805.74 ( 4.29%) Ops/sec create 4695.45 ( 0.00%) 4781.39 ( 1.83%) Ops/sec delete 173.72 ( 0.00%) 177.23 ( 2.02%) Ops/sec Transactions 14271.80 ( 0.00%) 14764.37 ( 3.45%) Ops/sec Read 37.00 ( 0.00%) 38.50 ( 4.05%) Ops/sec Write 18.20 ( 0.00%) 18.50 ( 1.65%) dd of a large file 3.15.0-rc5 3.15.0-rc5 vanilla proportion-v1r4 WallTime DownloadTar 75.00 ( 0.00%) 61.00 ( 18.67%) WallTime DD 423.00 ( 0.00%) 401.00 ( 5.20%) WallTime Delete 2.00 ( 0.00%) 5.00 (-150.00%) stutter (times mmap latency during large amounts of IO) 3.15.0-rc5 3.15.0-rc5 vanilla proportion-v1r4 Unit >5ms Delays 80252.0000 ( 0.00%) 81523.0000 ( -1.58%) Unit Mmap min 8.2118 ( 0.00%) 8.3206 ( -1.33%) Unit Mmap mean 17.4614 ( 0.00%) 17.2868 ( 1.00%) Unit Mmap stddev 24.9059 ( 0.00%) 34.6771 (-39.23%) Unit Mmap max 2811.6433 ( 0.00%) 2645.1398 ( 5.92%) Unit Mmap 90% 20.5098 ( 0.00%) 18.3105 ( 10.72%) Unit Mmap 93% 22.9180 ( 0.00%) 20.1751 ( 11.97%) Unit Mmap 95% 25.2114 ( 0.00%) 22.4988 ( 10.76%) Unit Mmap 99% 46.1430 ( 0.00%) 43.5952 ( 5.52%) Unit Ideal Tput 85.2623 ( 0.00%) 78.8906 ( 7.47%) Unit Tput min 44.0666 ( 0.00%) 43.9609 ( 0.24%) Unit Tput mean 45.5646 ( 0.00%) 45.2009 ( 0.80%) Unit Tput stddev 0.9318 ( 0.00%) 1.1084 (-18.95%) Unit Tput max 46.7375 ( 0.00%) 46.7539 ( -0.04%) This patch (of 3): We will like to unregister the sb shrinker before ->kill_sb(). This will allow cached objects to be counted without call to grab_super_passive() to update ref count on sb. We want to avoid locking during memory reclamation especially when we are skipping the memory reclaim when we are out of cached objects. This is safe because grab_super_passive does a try-lock on the sb->s_umount now, and so if we are in the unmount process, it won't ever block. That means what used to be a deadlock and races we were avoiding by using grab_super_passive() is now: shrinker umount down_read(shrinker_rwsem) down_write(sb->s_umount) shrinker_unregister down_write(shrinker_rwsem) <blocks> grab_super_passive(sb) down_read_trylock(sb->s_umount) <fails> <shrinker aborts> .... <shrinkers finish running> up_read(shrinker_rwsem) <unblocks> <removes shrinker> up_write(shrinker_rwsem) ->kill_sb() .... So it is safe to deregister the shrinker before ->kill_sb(). Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Chinner <david@fromorbit.com> Tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Jan Kara <jack@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: Don't return 0 from get_anon_bdevThomas Bächler2014-04-161-1/+4
| | | | | | | | | | | | | | | | | | | | Commit 9e30cc9595303b27b48 removed an internal mount. This has the side-effect that rootfs now has FSID 0. Many userspace utilities assume that st_dev in struct stat is never 0, so this change breaks a number of tools in early userspace. Since we don't know how many userspace programs are affected, make sure that FSID is at least 1. References: http://article.gmane.org/gmane.linux.kernel/1666905 References: http://permalink.gmane.org/gmane.linux.utilities.util-linux-ng/8557 Cc: 3.14 <stable@vger.kernel.org> Signed-off-by: Thomas Bächler <thomas@archlinux.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: H. Peter Anvin <hpa@zytor.com> Tested-by: Alexandre Demers <alexandre.f.demers@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fs: push sync_filesystem() down to the file system's remount_fs()Theodore Ts'o2014-03-131-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the no-op "mount -o mount /dev/xxx" operation when the file system is already mounted read-write causes an implied, unconditional syncfs(). This seems pretty stupid, and it's certainly documented or guaraunteed to do this, nor is it particularly useful, except in the case where the file system was mounted rw and is getting remounted read-only. However, it's possible that there might be some file systems that are actually depending on this behavior. In most file systems, it's probably fine to only call sync_filesystem() when transitioning from read-write to read-only, and there are some file systems where this is not needed at all (for example, for a pseudo-filesystem or something like romfs). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: linux-fsdevel@vger.kernel.org Cc: Christoph Hellwig <hch@infradead.org> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Evgeniy Dushistov <dushistov@mail.ru> Cc: Jan Kara <jack@suse.cz> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Anders Larsen <al@alarsen.net> Cc: Phillip Lougher <phillip@squashfs.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: xfs@oss.sgi.com Cc: linux-btrfs@vger.kernel.org Cc: linux-cifs@vger.kernel.org Cc: samba-technical@lists.samba.org Cc: codalist@coda.cs.cmu.edu Cc: linux-ext4@vger.kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net Cc: fuse-devel@lists.sourceforge.net Cc: cluster-devel@redhat.com Cc: linux-mtd@lists.infradead.org Cc: jfs-discussion@lists.sourceforge.net Cc: linux-nfs@vger.kernel.org Cc: linux-nilfs@vger.kernel.org Cc: linux-ntfs-dev@lists.sourceforge.net Cc: ocfs2-devel@oss.oracle.com Cc: reiserfs-devel@vger.kernel.org
* fs/super.c: sync ro remount after blocking writersAndrew Ruder2014-01-311-1/+2
| | | | | | | | | | | | | | | | | | Move sync_filesystem() after sb_prepare_remount_readonly(). If writers sneak in anywhere from sync_filesystem() to sb_prepare_remount_readonly() it can cause inodes to be dirtied and writeback to occur well after sys_mount() has completely successfully. This was spotted by corrupted ubifs filesystems on reboot, but appears that it can cause issues with any filesystem using writeback. Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> CC: Richard Weinberger <richard@nod.at> Co-authored-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Ruder <andrew.ruder@elecsyscorp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/super.c: fix WARN on alloc_super() fail pathVladimir Davydov2014-01-211-1/+2
| | | | | | | | | | | | | | On fail path alloc_super() calls destroy_super(), which issues a warning if the sb's s_mounts list is not empty, in particular if it has not been initialized. That said s_mounts must be initialized in alloc_super() before any possible failure, but currently it is initialized close to the end of the function leading to a useless warning dumped to log if either percpu_counter_init() or list_lru_init() fails. Let's fix this. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* get rid of s_files and files_lockAl Viro2013-11-091-13/+2
| | | | | | | | The only thing we need it for is alt-sysrq-r (emergency remount r/o) and these days we can do just as well without going through the list of files. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make freeing super_block rcu-delayedAl Viro2013-10-241-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* uninline destroy_super(), consolidate alloc_super()Al Viro2013-10-241-120/+86
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/super.c: fix lru_list leak for realAl Viro2013-10-011-2/+2
| | | | | | | | | Freeing ->s_{inode,dentry}_lru in deactivate_locked_super() is wrong; the right place is destroy_super(). As it is, we leak them if sget() decides that new superblock it has allocated (and never shown to anybody) isn't needed and should be freed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* super: fix for destroy lrusGlauber Costa2013-09-101-0/+3
| | | | | | | | | | | | This patch adds the missing call to list_lru_destroy (spotted by Li Zhong) and moves the deletion to after the shrinker is unregistered, as correctly spotted by Dave Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Dave Chinner <dchinner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* list_lru: dynamically adjust node arraysGlauber Costa2013-09-101-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently use a compile-time constant to size the node array for the list_lru structure. Due to this, we don't need to allocate any memory at initialization time. But as a consequence, the structures that contain embedded list_lru lists can become way too big (the superblock for instance contains two of them). This patch aims at ameliorating this situation by dynamically allocating the node arrays with the firmware provided nr_node_ids. Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: convert inode and dentry shrinking to be node awareDave Chinner2013-09-101-9/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that the shrinker is passing a node in the scan control structure, we can pass this to the the generic LRU list code to isolate reclaim to the lists on matching nodes. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* dcache: convert to use new lru list infrastructureDave Chinner2013-09-101-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [glommer@openvz.org: don't reintroduce double decrement of nr_unused_dentries, adapted for new LRU return codes] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* inode: convert inode lru list to generic lru list code.Dave Chinner2013-09-101-7/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [glommer@openvz.org: adapted for new LRU return codes] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* shrinker: convert superblock shrinkers to new APIDave Chinner2013-09-101-31/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert superblock shrinker to use the new count/scan API, and propagate the API changes through to the filesystem callouts. The filesystem callouts already use a count/scan API, so it's just changing counters to longs to match the VM API. This requires the dentry and inode shrinker callouts to be converted to the count/scan API. This is mainly a mechanical change. [glommer@openvz.org: use mult_frac for fractional proportions, build fixes] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* dentry: move to per-sb LRU locksDave Chinner2013-09-101-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the dentry LRUs being per-sb structures, there is no real need for a global dentry_lru_lock. The locking can be made more fine-grained by moving to a per-sb LRU lock, isolating the LRU operations of different filesytsems completely from each other. The need for this is independent of any performance consideration that may arise: in the interest of abstracting the lru operations away, it is mandatory that each lru works around its own lock instead of a global lock for all of them. [glommer@openvz.org: updated changelog ] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* super: fix calculation of shrinkable objects for small numbersGlauber Costa2013-09-101-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sysctl knob sysctl_vfs_cache_pressure is used to determine which percentage of the shrinkable objects in our cache we should actively try to shrink. It works great in situations in which we have many objects (at least more than 100), because the aproximation errors will be negligible. But if this is not the case, specially when total_objects < 100, we may end up concluding that we have no objects at all (total / 100 = 0, if total < 100). This is certainly not the biggest killer in the world, but may matter in very low kernel memory situations. Signed-off-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* prune_super(): sb->s_op is never NULLAl Viro2013-09-071-1/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* direct-io: Implement generic deferred AIO completionsChristoph Hellwig2013-09-041-9/+9
| | | | | | | | | | | | | | | | | | | | | | | Add support to the core direct-io code to defer AIO completions to user context using a workqueue. This replaces opencoded and less efficient code in XFS and ext4 (we save a memory allocation for each direct IO) and will be needed to properly support O_(D)SYNC for AIO. The communication between the filesystem and the direct I/O code requires a new buffer head flag, which is a bit ugly but not avoidable until the direct I/O code stops abusing the buffer_head structure for communicating with the filesystems. Currently this creates a per-superblock unbound workqueue for these completions, which is taken from an earlier patch by Jan Kara. I'm not really convinced about this use and would prefer a "normal" global workqueue with a high concurrency limit, but this needs further discussion. JK: Fixed ext4 part, dynamic allocation of the workqueue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* livelock avoidance in sget()Al Viro2013-07-201-15/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric Sandeen has found a nasty livelock in sget() - take a mount(2) about to fail. The superblock is on ->fs_supers, ->s_umount is held exclusive, ->s_active is 1. Along comes two more processes, trying to mount the same thing; sget() in each is picking that superblock, bumping ->s_count and trying to grab ->s_umount. ->s_active is 3 now. Original mount(2) finally gets to deactivate_locked_super() on failure; ->s_active is 2, superblock is still ->fs_supers because shutdown will *not* happen until ->s_active hits 0. ->s_umount is dropped and now we have two processes chasing each other: s_active = 2, A acquired ->s_umount, B blocked A sees that the damn thing is stillborn, does deactivate_locked_super() s_active = 1, A drops ->s_umount, B gets it A restarts the search and finds the same superblock. And bumps it ->s_active. s_active = 2, B holds ->s_umount, A blocked on trying to get it ... and we are in the earlier situation with A and B switched places. The root cause, of course, is that ->s_active should not grow until we'd got MS_BORN. Then failing ->mount() will have deactivate_locked_super() shut the damn thing down. Fortunately, it's easy to do - the key point is that grab_super() is called only for superblocks currently on ->fs_supers, so it can bump ->s_count and grab ->s_umount first, then check MS_BORN and bump ->s_active; we must never increment ->s_count for superblocks past ->kill_sb(), but grab_super() is never called for those. The bug is pretty old; we would've caught it by now, if not for accidental exclusion between sget() for block filesystems; the things like cgroup or e.g. mtd-based filesystems don't have anything of that sort, so they get bitten. The right way to deal with that is obviously to fix sget()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* hlist: drop the node parameter from iteratorsSasha Levin2013-02-271-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* idr: remove MAX_IDR_MASK and move left MAX_IDR_* into idr.cTejun Heo2013-02-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MAX_IDR_MASK is another weirdness in the idr interface. As idr covers whole positive integer range, it's defined as 0x7fffffff or INT_MAX. Its usage in idr_find(), idr_replace() and idr_remove() is bizarre. They basically mask off the sign bit and operate on the rest, so if the caller, by accident, passes in a negative number, the sign bit will be masked off and the remaining part will be used as if that was the input, which is worse than crashing. The constant is visible in idr.h and there are several users in the kernel. * drivers/i2c/i2c-core.c:i2c_add_numbered_adapter() Basically used to test if adap->nr is a negative number which isn't -1 and returns -EINVAL if so. idr_alloc() already has negative @start checking (w/ WARN_ON_ONCE), so this can go away. * drivers/infiniband/core/cm.c:cm_alloc_id() drivers/infiniband/hw/mlx4/cm.c:id_map_alloc() Used to wrap cyclic @start. Can be replaced with max(next, 0). Note that this type of cyclic allocation using idr is buggy. These are prone to spurious -ENOSPC failure after the first wraparound. * fs/super.c:get_anon_bdev() The ID allocated from ida is masked off before being tested whether it's inside valid range. ida allocated ID can never be a negative number and the masking is unnecessary. Update idr_*() functions to fail with -EINVAL when negative @id is specified and update other MAX_IDR_MASK users as described above. This leaves MAX_IDR_MASK without any user, remove it and relocate other MAX_IDR_* constants to lib/idr.c. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jean Delvare <khali@linux-fr.org> Cc: Roland Dreier <roland@kernel.org> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Hal Rosenstock <hal.rosenstock@gmail.com> Cc: "Marciniszyn, Mike" <mike.marciniszyn@intel.com> Cc: Jack Morgenstein <jackm@dev.mellanox.co.il> Cc: Or Gerlitz <ogerlitz@mellanox.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Wolfram Sang <wolfram@the-dreams.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: drop lock/unlock superMarco Stornelli2012-10-091-23/+0
| | | | | | | Removed s_lock from super_block and removed lock/unlock super. Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* idr: rename MAX_LEVEL to MAX_IDR_LEVELFengguang Wu2012-10-061-1/+1
| | | | | | | | | | | | | | | | | | | | To avoid name conflicts: drivers/video/riva/fbdev.c:281:9: sparse: preprocessor token MAX_LEVEL redefined While at it, also make the other names more consistent and add parentheses. [akpm@linux-foundation.org: repair fallout] [sfr@canb.auug.org.au: IB/mlx4: fix for MAX_ID_MASK to MAX_IDR_MASK name change] Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: walter harms <wharms@bfs.de> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Roland Dreier <roland@purestorage.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: push rcu_barrier() from deactivate_locked_super() to filesystemsKirill A. Shutemov2012-10-021-6/+0
| | | | | | | | | | | | | | | There's no reason to call rcu_barrier() on every deactivate_locked_super(). We only need to make sure that all delayed rcu free inodes are flushed before we destroy related cache. Removing rcu_barrier() from deactivate_locked_super() affects some fast paths. E.g. on my machine exit_group() of a last process in IPC namespace takes 0.07538s. rcu_barrier() takes 0.05188s of that time. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: kill write_super and sync_supersArtem Bityutskiy2012-08-041-40/+0
| | | | | | | | | | | | | | | | | | | | | | | Finally we can kill the 'sync_supers' kernel thread along with the '->write_super()' superblock operation because all the users are gone. Now every file-system is supposed to self-manage own superblock and its dirty state. The nice thing about killing this thread is that it improves power management. Indeed, 'sync_supers' is a source of monotonic system wake-ups - it woke up every 5 seconds no matter what - even if there were no dirty superblocks and even if there were no file-systems using this service (e.g., btrfs and journalled ext4 do not need it). So it was wasting power most of the time. And because the thread was in the core of the kernel, all systems had to have it. So I am quite happy to make it go away. Interestingly, this thread is a left-over from the pdflush kernel thread which was a self-forking kernel thread responsible for all the write-back in old Linux kernels. It was turned into per-block device BDI threads, and 'sync_supers' was a left-over. Thus, R.I.P, pdflush as well. Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-08-011-22/+230
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull second vfs pile from Al Viro: "The stuff in there: fsfreeze deadlock fixes by Jan (essentially, the deadlock reproduced by xfstests 068), symlink and hardlink restriction patches, plus assorted cleanups and fixes. Note that another fsfreeze deadlock (emergency thaw one) is *not* dealt with - the series by Fernando conflicts a lot with Jan's, breaks userland ABI (FIFREEZE semantics gets changed) and trades the deadlock for massive vfsmount leak; this is going to be handled next cycle. There probably will be another pull request, but that stuff won't be in it." Fix up trivial conflicts due to unrelated changes next to each other in drivers/{staging/gdm72xx/usb_boot.c, usb/gadget/storage_common.c} * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits) delousing target_core_file a bit Documentation: Correct s_umount state for freeze_fs/unfreeze_fs fs: Remove old freezing mechanism ext2: Implement freezing btrfs: Convert to new freezing mechanism nilfs2: Convert to new freezing mechanism ntfs: Convert to new freezing mechanism fuse: Convert to new freezing mechanism gfs2: Convert to new freezing mechanism ocfs2: Convert to new freezing mechanism xfs: Convert to new freezing code ext4: Convert to new freezing mechanism fs: Protect write paths by sb_start_write - sb_end_write fs: Skip atime update on frozen filesystem fs: Add freezing handling to mnt_want_write() / mnt_drop_write() fs: Improve filesystem freezing handling switch the protection of percpu_counter list to spinlock nfsd: Push mnt_want_write() outside of i_mutex btrfs: Push mnt_want_write() outside of i_mutex fat: Push mnt_want_write() outside of i_mutex ...
| * fs: Remove old freezing mechanismJan Kara2012-07-311-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | Now that all users are converted, we can remove functions, variables, and constants defined by the old freezing mechanism. BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa <kamal@canonical.com> Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com> Tested-by: Dann Frazier <dann.frazier@canonical.com> Tested-by: Massimo Morana <massimo.morana@canonical.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fs: Improve filesystem freezing handlingJan Kara2012-07-311-21/+230
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | vfs_check_frozen() tests are racy since the filesystem can be frozen just after the test is performed. Thus in write paths we can end up marking some pages or inodes dirty even though the file system is already frozen. This creates problems with flusher thread hanging on frozen filesystem. Another problem is that exclusion between ->page_mkwrite() and filesystem freezing has been handled by setting page dirty and then verifying s_frozen. This guaranteed that either the freezing code sees the faulted page, writes it, and writeprotects it again or we see s_frozen set and bail out of page fault. This works to protect from page being marked writeable while filesystem freezing is running but has an unpleasant artefact of leaving dirty (although unmodified and writeprotected) pages on frozen filesystem resulting in similar problems with flusher thread as the first problem. This patch aims at providing exclusion between write paths and filesystem freezing. We implement a writer-freeze read-write semaphore in the superblock. Actually, there are three such semaphores because of lock ranking reasons - one for page fault handlers (->page_mkwrite), one for all other writers, and one of internal filesystem purposes (used e.g. to track running transactions). Write paths which should block freezing (e.g. directory operations, ->aio_write(), ->page_mkwrite) hold reader side of the semaphore. Code freezing the filesystem takes the writer side. Only that we don't really want to bounce cachelines of the semaphores between CPUs for each write happening. So we implement the reader side of the semaphore as a per-cpu counter and the writer side is implemented using s_writers.frozen superblock field. [AV: microoptimize sb_start_write(); we want it fast in normal case] BugLink: https://bugs.launchpad.net/bugs/897421 Tested-by: Kamal Mostafa <kamal@canonical.com> Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com> Tested-by: Dann Frazier <dann.frazier@canonical.com> Tested-by: Massimo Morana <massimo.morana@canonical.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | vmscan: remove obsolete shrink_control commentMinchan Kim2012-07-311-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 09f363c7 ("vmscan: fix shrinker callback bug in fs/super.c") fixed a shrinker callback which was returning -1 when nr_to_scan is zero, which caused excessive slab scanning. But 635697c6 ("vmscan: fix initial shrinker size handling") fixed the problem, again so we can freely return -1 although nr_to_scan is zero. So let's revert 09f363c7 because the comment added in 09f363c7 made an unnecessary rule. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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