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33c3fc71c8
linux/fs
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Vladimir Davydov 33c3fc71c8 mm: introduce idle page tracking 
Knowing the portion of memory that is not used by a certain application or
memory cgroup (idle memory) can be useful for partitioning the system
efficiently, e.g.  by setting memory cgroup limits appropriately.
Currently, the only means to estimate the amount of idle memory provided
by the kernel is /proc/PID/{clear_refs,smaps}: the user can clear the
access bit for all pages mapped to a particular process by writing 1 to
clear_refs, wait for some time, and then count smaps:Referenced.  However,
this method has two serious shortcomings:

 - it does not count unmapped file pages
 - it affects the reclaimer logic

To overcome these drawbacks, this patch introduces two new page flags,
Idle and Young, and a new sysfs file, /sys/kernel/mm/page_idle/bitmap.
A page's Idle flag can only be set from userspace by setting bit in
/sys/kernel/mm/page_idle/bitmap at the offset corresponding to the page,
and it is cleared whenever the page is accessed either through page tables
(it is cleared in page_referenced() in this case) or using the read(2)
system call (mark_page_accessed()). Thus by setting the Idle flag for
pages of a particular workload, which can be found e.g.  by reading
/proc/PID/pagemap, waiting for some time to let the workload access its
working set, and then reading the bitmap file, one can estimate the amount
of pages that are not used by the workload.

The Young page flag is used to avoid interference with the memory
reclaimer.  A page's Young flag is set whenever the Access bit of a page
table entry pointing to the page is cleared by writing to the bitmap file.
If page_referenced() is called on a Young page, it will add 1 to its
return value, therefore concealing the fact that the Access bit was
cleared.

Note, since there is no room for extra page flags on 32 bit, this feature
uses extended page flags when compiled on 32 bit.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: kpageidle requires an MMU]
[akpm@linux-foundation.org: decouple from page-flags rework]
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Reviewed-by: Andres Lagar-Cavilla <andreslc@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Greg Thelen <gthelen@google.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-09-10 13:29:01 -07:00
..
9p 9p: fix return code of read() when count is 0 2015-08-23 14:21:36 -05:00
adfs fs/adfs: remove unneeded cast 2015-06-30 19:44:57 -07:00
affs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
afs net: Add a struct net parameter to sock_create_kern 2015-05-11 10:50:17 -04:00
autofs4 make simple_positive() public 2015-06-23 18:02:01 -04:00
befs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
bfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
cachefiles Merge branch 'fscache-fixes' into for-next 2015-06-23 18:01:30 -04:00
ceph fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
cifs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
coda fs: cleanup slight list_entry abuse 2015-06-23 18:01:59 -04:00
configfs configfs: fix kernel infoleak through user-controlled format string 2015-07-17 16:39:53 -07:00
cramfs
debugfs debugfs: Export bool read/write functions 2015-07-20 18:44:50 +01:00
devpts devpts: if initialization failed, don't crash when opening /dev/ptmx 2015-06-30 19:44:58 -07:00
dlm dlm for 4.3 2015-09-03 12:57:48 -07:00
ecryptfs Invalidate stale eCryptfs dcache entries caused by unlinked lower inodes 2015-09-08 11:26:17 -07:00
efivarfs Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2015-05-06 10:57:37 -07:00
efs fs/efs: femove unneeded cast 2015-06-25 17:00:42 -07:00
exofs pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
exportfs VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) 2015-02-22 11:38:41 -05:00
ext2 ext2: huge page fault support 2015-09-08 15:35:28 -07:00
ext4 ext4: start transaction before calling into DAX 2015-09-08 15:35:28 -07:00
f2fs Merge tag 'for-f2fs-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs 2015-09-03 13:10:22 -07:00
fat writeback: separate out include/linux/backing-dev-defs.h 2015-06-02 08:33:34 -06:00
freevxfs freevxfs: Grammar s/an negative/a negative/ 2015-08-07 13:59:24 +02:00
fscache FS-Cache: Retain the netfs context in the retrieval op earlier 2015-04-02 14:28:53 +01:00
fuse fs/fuse: fix ioctl type confusion 2015-08-16 12:35:44 -07:00
gfs2 fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hfsplus fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hostfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
hpfs hpfs: update ctime and mtime on directory modification 2015-09-03 11:55:30 -07:00
hugetlbfs hugetlbfs: add hugetlbfs_fallocate() 2015-09-08 15:35:28 -07:00
isofs VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
jbd2 jbd2: limit number of reserved credits 2015-08-04 11:21:52 -04:00
jffs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
jfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2015-09-03 12:28:30 -07:00
kernfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
lockd lockd: NLM grace period shouldn't block NFSv4 opens 2015-08-13 10:22:06 -04:00
logfs block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
minix Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
ncpfs ncpfs: successful rename() should invalidate caches for parents 2015-06-14 11:31:39 -04:00
nfs NFS client updates for Linux 4.3 2015-09-07 14:02:24 -07:00
nfs_common lockd: NLM grace period shouldn't block NFSv4 opens 2015-08-13 10:22:06 -04:00
nfsd NFS client updates for Linux 4.3 2015-09-07 14:02:24 -07:00
nilfs2 block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
nls
notify Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
ntfs ntfs: delete unnecessary checks before calling iput() 2015-09-04 16:54:41 -07:00
ocfs2 fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
omfs omfs: fix potential integer overflow in allocator 2015-05-28 18:25:19 -07:00
openpromfs
overlayfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
proc mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
pstore Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-07-03 15:20:57 -07:00
qnx4
qnx6 pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
quota Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
ramfs VFS: normal filesystems (and lustre): d_inode() annotations 2015-04-15 15:06:57 -04:00
reiserfs fs: create and use seq_show_option for escaping 2015-09-04 16:54:41 -07:00
romfs make new_sync_{read,write}() static 2015-04-11 22:29:40 -04:00
squashfs fs: cleanup slight list_entry abuse 2015-06-23 18:01:59 -04:00
sysfs vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
sysv pagemap.h: move dir_pages() over there 2015-06-23 18:02:00 -04:00
tracefs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
ubifs This pull request includes the following UBI/UBIFS changes: 2015-06-25 14:11:34 -07:00
udf udf: Don't modify filesystem for read-only mounts 2015-08-20 14:58:35 +02:00
ufs ufs_inode_get{frag,block}(): get rid of 'phys' argument 2015-07-06 17:40:05 -04:00
xfs xfs: huge page fault support 2015-09-08 15:35:28 -07:00
aio.c mm: move ->mremap() from file_operations to vm_operations_struct 2015-09-04 16:54:41 -07:00
anon_inodes.c
attr.c
bad_inode.c don't bother with most of the bad_file_ops methods 2015-02-20 04:03:58 -05:00
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-04-26 17:22:07 -07:00
binfmt_script.c
block_dev.c Merge branch 'akpm' (patches from Andrew) 2015-09-08 17:52:23 -07:00
buffer.c fs: use helper bio_add_page() instead of open coding on bi_io_vec 2015-08-13 12:32:00 -06:00
char_dev.c fs/char_dev.c: fix incorrect documentation for unregister_chrdev_region 2015-08-05 13:49:35 -07:00
compat_binfmt_elf.c
compat_ioctl.c ioctl_compat: handle FITRIM 2015-07-09 11:42:21 -07:00
compat.c
coredump.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
dax.c Merge branch 'akpm' (patches from Andrew) 2015-09-08 17:52:23 -07:00
dcache.c dcache: Reduce the scope of i_lock in d_splice_alias 2015-08-21 02:34:37 -04:00
dcookies.c
direct-io.c block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
drop_caches.c inode: convert inode_sb_list_lock to per-sb 2015-08-17 18:39:46 -04:00
eventfd.c eventfd: don't take the spinlock in eventfd_poll 2015-02-17 14:34:52 -08:00
eventpoll.c epoll: optimize setting task running after blocking 2015-02-13 21:21:40 -08:00
exec.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
fcntl.c
fhandle.c vfs: read file_handle only once in handle_to_path 2015-06-02 10:29:07 -07:00
file_table.c fs, file table: reinit files_stat.max_files after deferred memory initialisation 2015-08-07 04:39:40 +03:00
file.c fs/file.c: __fget() and dup2() atomicity rules 2015-07-01 02:31:08 -04:00
filesystems.c
fs_pin.c fs_pin: Allow for the possibility that m_list or s_list go unused. 2015-04-09 11:39:55 -05:00
fs_struct.c
fs-writeback.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-09-05 20:34:28 -07:00
inode.c inode: don't softlockup when evicting inodes 2015-08-18 10:20:09 -07:00
internal.h inode: rename i_wb_list to i_io_list 2015-08-17 23:38:10 -04:00
ioctl.c fsioctl.c: make generic_block_fiemap() signal-tolerant 2015-02-10 14:30:30 -08:00
Kconfig fs: Remove ext3 filesystem driver 2015-07-23 20:59:40 +02:00
Kconfig.binfmt mm: split ET_DYN ASLR from mmap ASLR 2015-04-14 16:49:05 -07:00
libfs.c fs: Set the size of empty dirs to 0. 2015-08-12 15:28:45 -05:00
locks.c fs: fix fs/locks.c kernel-doc warning 2015-08-31 16:27:25 -04:00
Makefile userfaultfd: buildsystem activation 2015-09-04 16:54:41 -07:00
mbcache.c
mount.h fs: use seq_open_private() for proc_mounts 2015-06-30 19:44:56 -07:00
mpage.c block: remove bio_get_nr_vecs() 2015-08-13 12:32:04 -06:00
namei.c vfs: Test for and handle paths that are unreachable from their mnt_root 2015-08-21 03:20:10 -04:00
namespace.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2015-09-01 16:13:25 -07:00
no-block.c
nsfs.c nsfs: Add a show_path method to fix mountinfo 2015-07-11 11:09:00 -05:00
open.c vfs: Commit to never having exectuables on proc and sysfs. 2015-07-10 10:39:25 -05:00
pipe.c VFS: assorted weird filesystems: d_inode() annotations 2015-04-15 15:06:58 -04:00
pnode.c mnt: Don't propagate unmounts to locked mounts 2015-04-02 20:34:20 -05:00
pnode.h mnt: Clarify and correct the disconnect logic in umount_tree 2015-07-22 20:33:27 -05:00
posix_acl.c fs/posix_acl.c: make posix_acl_create() safer and cleaner 2015-06-23 18:01:07 -04:00
proc_namespace.c fs: use seq_open_private() for proc_mounts 2015-06-30 19:44:56 -07:00
read_write.c new_sync_write(): discard ->ki_pos unless the return value is positive 2015-04-11 22:29:46 -04:00
readdir.c
select.c locking/arch: Rename set_mb() to smp_store_mb() 2015-05-19 08:32:00 +02:00
seq_file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2015-07-04 19:36:06 -07:00
signalfd.c signalfd: fix information leak in signalfd_copyinfo 2015-08-07 04:39:40 +03:00
splice.c Merge branch 'akpm' (patches from Andrew) 2015-06-24 20:47:21 -07:00
stack.c
stat.c VFS: assorted d_backing_inode() annotations 2015-04-15 15:06:59 -04:00
statfs.c
super.c Merge branch 'superblock-scaling' of git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-next into for-next 2015-08-21 02:31:20 -04:00
sync.c
timerfd.c
userfaultfd.c userfaultfd: avoid missing wakeups during refile in userfaultfd_read 2015-09-04 16:54:41 -07:00
utimes.c
xattr.c evm: fix potential race when removing xattrs 2015-05-21 13:28:47 -04:00