diff options
Diffstat (limited to 'mm/thrash.c')
| -rw-r--r-- | mm/thrash.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/mm/thrash.c b/mm/thrash.c index fabf2d0f5169..e53f7d02c17c 100644 --- a/mm/thrash.c +++ b/mm/thrash.c @@ -6,7 +6,7 @@ * Released under the GPL, see the file COPYING for details. * * Simple token based thrashing protection, using the algorithm - * described in: http://www.cs.wm.edu/~sjiang/token.pdf + * described in: http://www.cse.ohio-state.edu/hpcs/WWW/HTML/publications/abs05-1.html * * Sep 2006, Ashwin Chaugule <ashwin.chaugule@celunite.com> * Improved algorithm to pass token: @@ -30,8 +30,6 @@ 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) @@ -55,6 +53,8 @@ void grab_swap_token(struct mm_struct *mm) { int current_interval; unsigned int old_prio = mm->token_priority; + static unsigned int global_faults; + static unsigned int last_aging; global_faults++; @@ -67,6 +67,17 @@ void grab_swap_token(struct mm_struct *mm) if (!swap_token_mm) goto replace_token; + /* + * Usually, we don't need priority aging because long interval faults + * makes priority decrease quickly. But there is one exception. If the + * token owner task is sleeping, it never make long interval faults. + * Thus, we need a priority aging mechanism instead. The requirements + * of priority aging are + * 1) An aging interval is reasonable enough long. Too short aging + * interval makes quick swap token lost and decrease performance. + * 2) The swap token owner task have to get priority aging even if + * it's under sleep. + */ if ((global_faults - last_aging) > TOKEN_AGING_INTERVAL) { swap_token_mm->token_priority /= 2; last_aging = global_faults; |