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From: Rik van Riel <riel@redhat.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ken Chen <kenchen@google.com>, Ying Han <yinghan@google.com>,
	Hugh Dickins <hughd@google.com>, Nick Piggin <npiggin@gmail.com>,
	linux-mm@kvack.org, Minchan Kim <minchan.kim@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: don't flush TLB when propagate PTE access bit to struct page.
Date: Thu, 28 Oct 2010 23:43:12 -0400	[thread overview]
Message-ID: <4CCA42D0.5090603@redhat.com> (raw)
In-Reply-To: <20101029114529.4d3a8b9c.kamezawa.hiroyu@jp.fujitsu.com>

On 10/28/2010 10:45 PM, KAMEZAWA Hiroyuki wrote:

> Hmm. Without flushing anywhere in memory reclaim path, a process which
> cause page fault and enter vmscan will not see his own recent access bit on
> pages in LRU ?

Worse still, because kernel threads do a lazy mmu switch, even
page faulting in the process will not cause the TLB entries to
be flushed.

> I think it should be flushed at least once..

A periodic flush may make sense.

Maybe something along the lines of if the TLB has not been
flushed for over a second (we can see that in timer or scheduler
code), flush it?

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  reply	other threads:[~2010-10-29  3:43 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-27 17:21 [PATCH] mm: don't flush TLB when propagate PTE access bit to struct page Ying Han
2010-10-27 18:05 ` Rik van Riel
2010-10-27 18:22   ` Nick Piggin
2010-10-27 18:37     ` Nick Piggin
2010-10-27 19:13       ` Hugh Dickins
2010-10-27 20:35         ` Ying Han
2010-10-28  0:11           ` KAMEZAWA Hiroyuki
2010-10-29  1:30             ` Ken Chen
2010-10-29  2:45               ` KAMEZAWA Hiroyuki
2010-10-29  3:43                 ` Rik van Riel [this message]
2010-10-29  4:27                   ` Minchan Kim
2010-10-29 12:31                     ` Rik van Riel
2010-10-29 13:03                       ` Minchan Kim
2010-10-29 13:15                         ` Rik van Riel
2010-10-30  0:20                           ` Minchan Kim
2010-10-27 20:19   ` Ying Han
2010-10-28 11:53     ` Rik van Riel

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