Messages in this thread Patch in this message | | | Date | Wed, 22 Apr 2009 12:16:41 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [PATCH] memcg: remove trylock_page_cgroup |
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How about this ? worth to be tested, I think. -Kame == From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Before synchronized-LRU patch, mem cgroup had its own LRU lock. And there was a code which does # assume mz as per zone struct of memcg.
spin_lock mz->lru_lock lock_page_cgroup(pc). and lock_page_cgroup(pc) spin_lock mz->lru_lock
because we cannot locate "mz" until we see pc->page_cgroup, we used trylock(). But now, we don't have mz->lru_lock. All cgroup uses zone->lru_lock for handling list. Moreover, manipulation of LRU depends on global LRU now and we can isolate page from LRU by very generic way.(isolate_lru_page()). So, this kind of trylock is not necessary now.
I thought I removed all trylock in synchronized-LRU patch but there is still one. This patch removes trylock used in memcontrol.c and its definition. If someone needs, he should add this again with enough reason.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- include/linux/page_cgroup.h | 5 ----- mm/memcontrol.c | 3 +-- 2 files changed, 1 insertion(+), 7 deletions(-)
Index: mmotm-2.6.30-Apr21/include/linux/page_cgroup.h =================================================================== --- mmotm-2.6.30-Apr21.orig/include/linux/page_cgroup.h +++ mmotm-2.6.30-Apr21/include/linux/page_cgroup.h @@ -61,11 +61,6 @@ static inline void lock_page_cgroup(stru bit_spin_lock(PCG_LOCK, &pc->flags); } -static inline int trylock_page_cgroup(struct page_cgroup *pc) -{ - return bit_spin_trylock(PCG_LOCK, &pc->flags); -} - static inline void unlock_page_cgroup(struct page_cgroup *pc) { bit_spin_unlock(PCG_LOCK, &pc->flags); Index: mmotm-2.6.30-Apr21/mm/memcontrol.c =================================================================== --- mmotm-2.6.30-Apr21.orig/mm/memcontrol.c +++ mmotm-2.6.30-Apr21/mm/memcontrol.c @@ -1148,8 +1148,7 @@ static int mem_cgroup_move_account(struc from_mz = mem_cgroup_zoneinfo(from, nid, zid); to_mz = mem_cgroup_zoneinfo(to, nid, zid); - if (!trylock_page_cgroup(pc)) - return ret; + lock_page_cgroup(pc); if (!PageCgroupUsed(pc)) goto out;
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