From d7911ef30cb7bec52234c2b7a5c275ac8f07905a Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Wed, 15 Jun 2011 15:08:15 -0700 Subject: vmscan: implement swap token priority aging While testing for memcg aware swap token, I observed a swap token was often grabbed an intermittent running process (eg init, auditd) and they never release a token. Why? Some processes (eg init, auditd, audispd) wake up when a process exiting. And swap token can be get first page-in process when a process exiting makes no swap token owner. Thus such above intermittent running process often get a token. And currently, swap token priority is only decreased at page fault path. Then, if the process sleep immediately after to grab swap token, the swap token priority never be decreased. That's obviously undesirable. This patch implement very poor (and lightweight) priority aging. It only be affect to the above corner case and doesn't change swap tendency workload performance (eg multi process qsbench load) Signed-off-by: KOSAKI Motohiro Reviewed-by: Rik van Riel Reviewed-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/thrash.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/thrash.c b/mm/thrash.c index 17d9e29e4c9c..fabf2d0f5169 100644 --- a/mm/thrash.c +++ b/mm/thrash.c @@ -25,10 +25,13 @@ #include +#define TOKEN_AGING_INTERVAL (0xFF) + static DEFINE_SPINLOCK(swap_token_lock); struct mm_struct *swap_token_mm; struct mem_cgroup *swap_token_memcg; static unsigned int global_faults; +static unsigned int last_aging; #ifdef CONFIG_CGROUP_MEM_RES_CTLR static struct mem_cgroup *swap_token_memcg_from_mm(struct mm_struct *mm) @@ -64,6 +67,11 @@ void grab_swap_token(struct mm_struct *mm) if (!swap_token_mm) goto replace_token; + if ((global_faults - last_aging) > TOKEN_AGING_INTERVAL) { + swap_token_mm->token_priority /= 2; + last_aging = global_faults; + } + if (mm == swap_token_mm) { mm->token_priority += 2; goto update_priority; @@ -81,7 +89,7 @@ void grab_swap_token(struct mm_struct *mm) goto replace_token; update_priority: - trace_update_swap_token_priority(mm, old_prio); + trace_update_swap_token_priority(mm, old_prio, swap_token_mm); out: mm->faultstamp = global_faults; @@ -94,6 +102,7 @@ replace_token: trace_replace_swap_token(swap_token_mm, mm); swap_token_mm = mm; swap_token_memcg = swap_token_memcg_from_mm(mm); + last_aging = global_faults; goto out; } -- cgit v1.2.3-70-g09d2