From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Rik van Riel <riel@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Johannes Weiner <hannes@cmpxchg.org>, Jan Kara <jack@suse.cz>,
Mel Gorman <mgorman@techsingularity.net>,
Peter Zijlstra <peterz@infradead.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: page_waitqueue() considered harmful
Date: Tue, 27 Sep 2016 02:11:32 +0300 [thread overview]
Message-ID: <20160926231132.GA17069@node.shutemov.name> (raw)
In-Reply-To: <1474925009.17726.61.camel@redhat.com>
On Mon, Sep 26, 2016 at 05:23:29PM -0400, Rik van Riel wrote:
> On Mon, 2016-09-26 at 13:58 -0700, Linus Torvalds wrote:
>
> > Is there really any reason for that incredible indirection? Do we
> > really want to make the page_waitqueue() be a per-zone thing at all?
> > Especially since all those wait-queues won't even be *used* unless
> > there is actual IO going on and people are really getting into
> > contention on the page lock.. Why isn't the page_waitqueue() just one
> > statically sized array?
>
> Why are we touching file pages at all during fork()?
We are not.
Unless the vma has private pages (vma->anon_vma is not NULL).
See first lines for copy_page_range().
We probably can go futher and skip non-private pages within file VMA.
But we would need to touch struct page in this case, so it doesn't make
sense.
--
Kirill A. Shutemov
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next prev parent reply other threads:[~2016-09-26 23:11 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-26 20:58 page_waitqueue() considered harmful Linus Torvalds
2016-09-26 21:23 ` Rik van Riel
2016-09-26 21:30 ` Linus Torvalds
2016-09-26 23:11 ` Kirill A. Shutemov [this message]
2016-09-27 1:01 ` Rik van Riel
2016-09-27 7:30 ` Peter Zijlstra
2016-09-27 8:54 ` Mel Gorman
2016-09-27 9:11 ` Kirill A. Shutemov
2016-09-27 9:42 ` Mel Gorman
2016-09-27 9:52 ` Minchan Kim
2016-09-27 12:11 ` Kirill A. Shutemov
2016-09-29 8:01 ` Peter Zijlstra
2016-09-29 12:55 ` Nicholas Piggin
2016-09-29 13:16 ` Peter Zijlstra
2016-09-29 13:54 ` Nicholas Piggin
2016-09-29 15:05 ` Rik van Riel
2016-09-27 8:03 ` Jan Kara
2016-09-27 8:31 ` Mel Gorman
2016-09-27 14:34 ` Peter Zijlstra
2016-09-27 15:08 ` Nicholas Piggin
2016-09-27 16:31 ` Linus Torvalds
2016-09-27 16:49 ` Peter Zijlstra
2016-09-28 10:45 ` Mel Gorman
2016-09-28 11:11 ` Peter Zijlstra
2016-09-28 16:10 ` Linus Torvalds
2016-09-29 13:08 ` Peter Zijlstra
2016-10-03 10:47 ` Mel Gorman
2016-09-27 14:53 ` Nicholas Piggin
2016-09-27 15:17 ` Nicholas Piggin
2016-09-27 16:52 ` Peter Zijlstra
2016-09-27 17:06 ` Nicholas Piggin
2016-09-28 7:05 ` Peter Zijlstra
2016-09-28 11:05 ` Paul E. McKenney
2016-09-28 11:16 ` Peter Zijlstra
2016-09-28 12:58 ` Paul E. McKenney
2016-09-29 1:31 ` Nicholas Piggin
2016-09-29 2:12 ` Paul E. McKenney
2016-09-29 6:21 ` Peter Zijlstra
2016-09-29 6:42 ` Nicholas Piggin
2016-09-29 7:14 ` Peter Zijlstra
2016-09-29 7:43 ` Peter Zijlstra
2016-09-28 7:40 ` Mel Gorman
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