lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

memcg: fix shmem's swap accounting

Browse Source 
Now, you can see following even when swap accounting is enabled.

 1. Create Group 01, and 02.
 2. allocate a "file" on tmpfs by a task under 01.
 3. swap out the "file" (by memory pressure)
 4. Read "file" from a task in group 02.
 5. the charge of "file" is moved to group 02.

This is not ideal behavior. This is because SwapCache which was loaded
by read-ahead is not taken into account..

This is a patch to fix shmem's swapcache behavior.
  - remove mem_cgroup_cache_charge_swapin().
  - Add SwapCache handler routine to mem_cgroup_cache_charge().
    By this, shmem's file cache is charged at add_to_page_cache()
    with GFP_NOWAIT.
  - pass the page of swapcache to shrink_mem_cgroup.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki
2009-01-07 18:08:35 -08:00
committed by Linus Torvalds
parent 544122e5e0
commit b5a84319a4
4 changed files with 76 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
mm/shmem.c
View File

@@ -929,11 +929,11 @@ found:
if (!inode)
goto out;
/*
* Charge page using GFP_HIGHUSER_MOVABLE while we can wait.
* charged back to the user(not to caller) when swap account is used.
* Charge page using GFP_KERNEL while we can wait.
* Charged back to the user(not to caller) when swap account is used.
* add_to_page_cache() will be called with GFP_NOWAIT.
*/
error = mem_cgroup_cache_charge_swapin(page, current->mm, GFP_KERNEL,
true);
error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
if (error)
goto out;
error = radix_tree_preload(GFP_KERNEL);
@@ -1270,16 +1270,6 @@ repeat:
goto repeat;
}
wait_on_page_locked(swappage);
/*
* We want to avoid charge at add_to_page_cache().
* charge against this swap cache here.
*/
if (mem_cgroup_cache_charge_swapin(swappage,
current->mm, gfp & GFP_RECLAIM_MASK, false)) {
page_cache_release(swappage);
error = -ENOMEM;
goto failed;
}
page_cache_release(swappage);
goto repeat;
}
@@ -1334,15 +1324,19 @@ repeat:
} else {
shmem_swp_unmap(entry);
spin_unlock(&info->lock);
unlock_page(swappage);
page_cache_release(swappage);
if (error == -ENOMEM) {
/* allow reclaim from this memory cgroup */
error = mem_cgroup_shrink_usage(current->mm,
error = mem_cgroup_shrink_usage(swappage,
current->mm,
gfp);
if (error)
if (error) {
unlock_page(swappage);
page_cache_release(swappage);
goto failed;
}
}
unlock_page(swappage);
page_cache_release(swappage);
goto repeat;
}
} else if (sgp == SGP_READ && !filepage) {