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SubjectRe: [PATCH v5 5/9] memcg: add dirty page accounting infrastructure
On Fri, Feb 25, 2011 at 01:35:56PM -0800, Greg Thelen wrote:
> Add memcg routines to track dirty, writeback, and unstable_NFS pages.
> These routines are not yet used by the kernel to count such pages.
> A later change adds kernel calls to these new routines.
>
> Signed-off-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
> ---
> Changelog since v1:
> - Renamed "nfs"/"total_nfs" to "nfs_unstable"/"total_nfs_unstable" in per cgroup
> memory.stat to match /proc/meminfo.
> - Rename (for clarity):
> - mem_cgroup_write_page_stat_item -> mem_cgroup_page_stat_item
> - mem_cgroup_read_page_stat_item -> mem_cgroup_nr_pages_item
> - Remove redundant comments.
> - Made mem_cgroup_move_account_page_stat() inline.
>
> include/linux/memcontrol.h | 5 ++-
> mm/memcontrol.c | 87 ++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 83 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 3da48ae..e1f70a9 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -25,9 +25,12 @@ struct page_cgroup;
> struct page;
> struct mm_struct;
>
> -/* Stats that can be updated by kernel. */
> +/* mem_cgroup page counts accessed by kernel. */

I confused by 'kernel', 'access'?
So, What's the page counts accessed by user?
I don't like such words.

Please, clarify the comment.
'Stats of page that can be tracking by memcg' or whatever.

> enum mem_cgroup_page_stat_item {
> MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
> + MEMCG_NR_FILE_DIRTY, /* # of dirty pages in page cache */
> + MEMCG_NR_FILE_WRITEBACK, /* # of pages under writeback */
> + MEMCG_NR_FILE_UNSTABLE_NFS, /* # of NFS unstable pages */
> };
>
> extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 1c2704a..38f786b 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -92,8 +92,11 @@ enum mem_cgroup_stat_index {
> */
> MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
> MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
> - MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
> MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
> + MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
> + MEM_CGROUP_STAT_FILE_DIRTY, /* # of dirty pages in page cache */
> + MEM_CGROUP_STAT_FILE_WRITEBACK, /* # of pages under writeback */
> + MEM_CGROUP_STAT_FILE_UNSTABLE_NFS, /* # of NFS unstable pages */
> MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
> MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */
> MEM_CGROUP_STAT_NSTATS,
> @@ -1622,6 +1625,44 @@ void mem_cgroup_update_page_stat(struct page *page,
> ClearPageCgroupFileMapped(pc);
> idx = MEM_CGROUP_STAT_FILE_MAPPED;
> break;
> +
> + case MEMCG_NR_FILE_DIRTY:
> + /* Use Test{Set,Clear} to only un/charge the memcg once. */
> + if (val > 0) {
> + if (TestSetPageCgroupFileDirty(pc))
> + val = 0;
> + } else {
> + if (!TestClearPageCgroupFileDirty(pc))
> + val = 0;
> + }
> + idx = MEM_CGROUP_STAT_FILE_DIRTY;
> + break;
> +
> + case MEMCG_NR_FILE_WRITEBACK:
> + /*
> + * This counter is adjusted while holding the mapping's
> + * tree_lock. Therefore there is no race between settings and
> + * clearing of this flag.
> + */
> + if (val > 0)
> + SetPageCgroupFileWriteback(pc);
> + else
> + ClearPageCgroupFileWriteback(pc);
> + idx = MEM_CGROUP_STAT_FILE_WRITEBACK;
> + break;
> +
> + case MEMCG_NR_FILE_UNSTABLE_NFS:
> + /* Use Test{Set,Clear} to only un/charge the memcg once. */
> + if (val > 0) {
> + if (TestSetPageCgroupFileUnstableNFS(pc))
> + val = 0;
> + } else {
> + if (!TestClearPageCgroupFileUnstableNFS(pc))
> + val = 0;
> + }
> + idx = MEM_CGROUP_STAT_FILE_UNSTABLE_NFS;
> + break;

This part can be simplified by some macro work.
But it's another issue.

> +
> default:
> BUG();
> }
> @@ -2181,6 +2222,17 @@ void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail)
> }
> #endif
>
> +static inline
> +void mem_cgroup_move_account_page_stat(struct mem_cgroup *from,
> + struct mem_cgroup *to,
> + enum mem_cgroup_stat_index idx)
> +{
> + preempt_disable();
> + __this_cpu_dec(from->stat->count[idx]);
> + __this_cpu_inc(to->stat->count[idx]);
> + preempt_enable();
> +}
> +
> /**
> * mem_cgroup_move_account - move account of the page
> * @page: the page
> @@ -2229,13 +2281,18 @@ static int mem_cgroup_move_account(struct page *page,
>
> move_lock_page_cgroup(pc, &flags);
>
> - if (PageCgroupFileMapped(pc)) {
> - /* Update mapped_file data for mem_cgroup */
> - preempt_disable();
> - __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
> - __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
> - preempt_enable();
> - }
> + if (PageCgroupFileMapped(pc))
> + mem_cgroup_move_account_page_stat(from, to,
> + MEM_CGROUP_STAT_FILE_MAPPED);
> + if (PageCgroupFileDirty(pc))
> + mem_cgroup_move_account_page_stat(from, to,
> + MEM_CGROUP_STAT_FILE_DIRTY);
> + if (PageCgroupFileWriteback(pc))
> + mem_cgroup_move_account_page_stat(from, to,
> + MEM_CGROUP_STAT_FILE_WRITEBACK);
> + if (PageCgroupFileUnstableNFS(pc))
> + mem_cgroup_move_account_page_stat(from, to,
> + MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
> mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages);
> if (uncharge)
> /* This is not "cancel", but cancel_charge does all we need. */
> @@ -3681,6 +3738,9 @@ enum {
> MCS_PGPGIN,
> MCS_PGPGOUT,
> MCS_SWAP,
> + MCS_FILE_DIRTY,
> + MCS_WRITEBACK,
> + MCS_UNSTABLE_NFS,
> MCS_INACTIVE_ANON,
> MCS_ACTIVE_ANON,
> MCS_INACTIVE_FILE,
> @@ -3703,6 +3763,9 @@ struct {
> {"pgpgin", "total_pgpgin"},
> {"pgpgout", "total_pgpgout"},
> {"swap", "total_swap"},
> + {"dirty", "total_dirty"},
> + {"writeback", "total_writeback"},
> + {"nfs_unstable", "total_nfs_unstable"},
> {"inactive_anon", "total_inactive_anon"},
> {"active_anon", "total_active_anon"},
> {"inactive_file", "total_inactive_file"},
> @@ -3732,6 +3795,14 @@ mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
> s->stat[MCS_SWAP] += val * PAGE_SIZE;
> }
>
> + /* dirty stat */
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY);
> + s->stat[MCS_FILE_DIRTY] += val * PAGE_SIZE;
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_WRITEBACK);
> + s->stat[MCS_WRITEBACK] += val * PAGE_SIZE;
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
> + s->stat[MCS_UNSTABLE_NFS] += val * PAGE_SIZE;
> +
> /* per zone stat */
> val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
> s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
> --
> 1.7.3.1
>

--
Kind regards,
Minchan Kim


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