[Devel] Re: [PATCH 05/10] memcg: add dirty page accounting infrastructure
Minchan Kim
minchan.kim at gmail.com
Tue Oct 5 09:09:29 PDT 2010
On Sun, Oct 03, 2010 at 11:58:00PM -0700, 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 at google.com>
> Signed-off-by: Andrea Righi <arighi at develer.com>
> ---
> include/linux/memcontrol.h | 3 +
> mm/memcontrol.c | 89 ++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 84 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 7c7bec4..6303da1 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -28,6 +28,9 @@ struct mm_struct;
> /* Stats that can be updated by kernel. */
> enum mem_cgroup_write_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 267d774..f40839f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -85,10 +85,13 @@ 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_PGPGIN_COUNT, /* # of pages paged in */
> MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
> 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 */
> /* incremented at every pagein/pageout */
> MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
> @@ -1626,6 +1629,48 @@ 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))
> + /* already set */
Nitpick.
The comment doesn't give any useful information.
It looks like redundant.
> + val = 0;
> + } else {
> + if (!TestClearPageCgroupFileDirty(pc))
> + /* already cleared */
Ditto
> + 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))
> + /* already set */
Ditto
> + val = 0;
> + } else {
> + if (!TestClearPageCgroupFileUnstableNFS(pc))
> + /* already cleared */
Ditto
> + val = 0;
> + }
> + idx = MEM_CGROUP_STAT_FILE_UNSTABLE_NFS;
> + break;
> +
> default:
> BUG();
> }
> @@ -2133,6 +2178,16 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
> memcg_check_events(mem, pc->page);
> }
>
> +static 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
> * @pc: page_cgroup of the page.
> @@ -2159,13 +2214,18 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
> VM_BUG_ON(!PageCgroupUsed(pc));
> VM_BUG_ON(pc->mem_cgroup != from);
>
> - 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, pc, false);
> if (uncharge)
> /* This is not "cancel", but cancel_charge does all we need. */
> @@ -3545,6 +3605,9 @@ enum {
> MCS_PGPGIN,
> MCS_PGPGOUT,
> MCS_SWAP,
> + MCS_FILE_DIRTY,
> + MCS_WRITEBACK,
> + MCS_UNSTABLE_NFS,
> MCS_INACTIVE_ANON,
> MCS_ACTIVE_ANON,
> MCS_INACTIVE_FILE,
> @@ -3567,6 +3630,9 @@ struct {
> {"pgpgin", "total_pgpgin"},
> {"pgpgout", "total_pgpgout"},
> {"swap", "total_swap"},
> + {"dirty", "total_dirty"},
> + {"writeback", "total_writeback"},
> + {"nfs", "total_nfs"},
> {"inactive_anon", "total_inactive_anon"},
> {"active_anon", "total_active_anon"},
> {"inactive_file", "total_inactive_file"},
> @@ -3596,6 +3662,13 @@ mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
> s->stat[MCS_SWAP] += val * PAGE_SIZE;
> }
>
> + 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;
> --
> 1.7.1
>
> --
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>
--
Kind regards,
Minchan Kim
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