Messages in this thread | | | Subject | Re: [PATCH 4/13] memcg: force_empty moving account | From | Peter Zijlstra <> | Date | Mon, 22 Sep 2008 16:23:40 +0200 |
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On Mon, 2008-09-22 at 20:00 +0900, KAMEZAWA Hiroyuki wrote:
> + /* For avoiding race with speculative page cache handling. */ > + if (!PageLRU(page) || !get_page_unless_zero(page)) { > + list_move(&pc->lru, list); > + spin_unlock_irqrestore(&mz->lru_lock, flags); > + yield();
Gah, no way!
> + spin_lock_irqsave(&mz->lru_lock, flags); > + continue; > + } > + if (!trylock_page(page)) { > + list_move(&pc->lru, list); > put_page(page); > - if (--count <= 0) { > - count = FORCE_UNCHARGE_BATCH; > - cond_resched(); > - } > - } else > - cond_resched(); > - spin_lock_irqsave(&mz->lru_lock, flags); > + spin_unlock_irqrestore(&mz->lru_lock, flags); > + yield();
Seriously?!
> + spin_lock_irqsave(&mz->lru_lock, flags); > + continue; > + } > + if (mem_cgroup_move_account(page, pc, mem, &init_mem_cgroup)) { > + /* some confliction */ > + list_move(&pc->lru, list); > + unlock_page(page); > + put_page(page); > + spin_unlock_irqrestore(&mz->lru_lock, flags); > + yield();
Inflicting pain..
> + spin_lock_irqsave(&mz->lru_lock, flags); > + } else { > + unlock_page(page); > + put_page(page); > + } > + if (atomic_read(&mem->css.cgroup->count) > 0) > + break; > } > spin_unlock_irqrestore(&mz->lru_lock, flags);
do _NOT_ use yield() ever! unless you know what you're doing, and probably not even then.
NAK!
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