From: Nikita Danilov <nikita@clusterfs.com>
To: "liyu@LAN" <liyu@ccoss.com.cn>
Cc: linux-kernel@vger.kernel.org
Subject: Re: one question about LRU mechanism
Date: Wed, 15 Jun 2005 15:29:15 +0400 [thread overview]
Message-ID: <17072.4363.161693.887061@gargle.gargle.HOWL> (raw)
In-Reply-To: <1118817991.5828.23.camel@liyu.ccoss.com.cn>
liyu@LAN writes:
[...]
>
> /************************************************************/
> while (scan++ < nr_to_scan && !list_empty(src)) {
> page = lru_to_page(src);
> prefetchw_prev_lru_page(page, src, flags);
>
> if (!TestClearPageLRU(page))
> BUG();
> list_del(&page->lru);
[...]
>
> /***************************************************/
> while (scan++ < nr_to_scan && !list_empty(src->prev)) {
list_empty(something) and list_empty(something->prev) are equivalent for
well-formed lists.
list_empty(src) check in isolate_lru_pages() is for pathological case
when active list becomes empty. Also active and inactive lists are not
LRU, they are closer to second-chance-FIFO, it is _together_ that they
emulate LRU.
Nikita.
prev parent reply other threads:[~2005-06-15 11:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-15 5:12 liyu@WAN
2005-06-15 5:25 ` William Lee Irwin III
2005-06-15 6:46 ` liyu@LAN
2005-06-15 7:29 ` William Lee Irwin III
2005-06-15 7:57 ` Paolo Ornati
2005-06-15 11:29 ` Nikita Danilov [this message]
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