From: Ben Gamari <bgamari@gmail.com>
To: Mel Gorman <mel@csn.ul.ie>, Andrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan.kim@gmail.com>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Rik van Riel <riel@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Nick Piggin <npiggin@kernel.dk>
Subject: Re: [RFC 1/2] deactive invalidated pages
Date: Tue, 23 Nov 2010 09:55:49 -0500 [thread overview]
Message-ID: <87k4k49jii.fsf@gmail.com> (raw)
In-Reply-To: <20101123093859.GE19571@csn.ul.ie>
On Tue, 23 Nov 2010 09:38:59 +0000, Mel Gorman <mel@csn.ul.ie> wrote:
> > If it's mapped pagecache then the user was being a bit silly (or didn't
> > know that some other process had mapped the file). In which case we
> > need to decide what to do - leave the page alone, deactivate it, or
> > half-deactivate it as this patch does.
> >
>
> What are the odds of an fadvise() user having used mincore() in advance
> to determine if the page was in use by another process? I would guess
> "low" so this half-deactivate gives a chance for the page to be promoted
> again as well as a chance for the flusher threads to clean the page if
> it really is to be reclaimed.
>
Do we really want to make the user jump through such hoops as using
mincore() just to get the kernel to handle use-once pages properly?
I hope the answer is no. I know that fadvise isn't supposed to be a
magic bullet, but it would be nice if more processes would use it to
indicate their access patterns and the only way that will happen is if
it is reasonably straightforward to use.
- Ben
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next prev parent reply other threads:[~2010-11-23 14:55 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-21 14:30 [RFC 1/2] deactive invalidated pages Minchan Kim
2010-11-21 14:30 ` [RFC 2/2] Prevent promotion of page in madvise_dontneed Minchan Kim
2010-11-21 14:38 ` Minchan Kim
2010-11-21 16:34 ` Ben Gamari
2010-11-22 0:31 ` Minchan Kim
2010-11-22 22:21 ` Andrew Morton
2010-11-23 4:57 ` Minchan Kim
2010-11-23 9:50 ` Mel Gorman
2010-11-23 23:49 ` Minchan Kim
2010-11-21 15:21 ` [RFC 1/2] deactive invalidated pages Ben Gamari
2010-11-23 7:16 ` KOSAKI Motohiro
2010-11-23 13:48 ` Ben Gamari
2010-11-23 23:48 ` Minchan Kim
2010-11-23 14:49 ` [RFC PATCH] fadvise support in rsync Ben Gamari
2010-11-23 15:35 ` Pádraig Brady
2010-11-24 0:17 ` KOSAKI Motohiro
2010-11-23 14:49 ` [PATCH 1/3] Add fadvise interface wrapper Ben Gamari
2010-11-23 14:49 ` [PATCH 2/3] Inform kernel of FADV_DONTNEED hint in sender Ben Gamari
2010-11-23 14:49 ` [PATCH 3/3] Inform kernel of FADV_DONTNEED hint in receiver Ben Gamari
2010-11-22 1:17 ` [RFC 1/2] deactive invalidated pages Rik van Riel
2010-11-22 22:14 ` Andrew Morton
2010-11-23 4:52 ` Minchan Kim
2010-11-23 5:01 ` Andrew Morton
2010-11-23 5:23 ` Minchan Kim
2010-11-23 5:22 ` Andrew Morton
2010-11-23 5:45 ` Minchan Kim
2010-11-23 5:48 ` Andrew Morton
2010-11-23 6:05 ` Minchan Kim
2010-11-23 7:15 ` Andrew Morton
2010-11-23 7:44 ` Minchan Kim
2010-11-23 7:53 ` Andrew Morton
2010-11-23 8:02 ` Minchan Kim
2010-11-23 9:43 ` Mel Gorman
2010-11-23 23:32 ` Minchan Kim
2010-11-23 9:38 ` Mel Gorman
2010-11-23 14:55 ` Ben Gamari [this message]
2010-11-23 14:58 ` Mel Gorman
2010-11-23 20:35 ` Andrew Morton
2010-11-23 22:10 ` Mel Gorman
2010-11-23 23:45 ` Minchan Kim
2010-11-24 18:01 ` Mel Gorman
2010-11-23 7:16 ` KOSAKI Motohiro
2010-11-23 7:40 ` Minchan Kim
2010-11-23 7:42 ` Andrew Morton
2010-11-23 8:01 ` KOSAKI Motohiro
2010-11-23 8:44 ` Minchan Kim
2010-11-23 9:02 ` KOSAKI Motohiro
2010-11-23 9:05 ` Minchan Kim
2010-11-23 9:07 ` Minchan Kim
2010-11-23 14:57 ` Ben Gamari
2010-11-24 0:13 ` KOSAKI Motohiro
2010-11-23 9:28 ` Mel Gorman
2010-11-23 23:24 ` Minchan Kim
2010-11-24 10:02 ` Mel Gorman
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