From: Linus Torvalds <torvalds@osdl.org>
To: Andrew Morton <akpm@osdl.org>
Cc: manfred@colorfullife.com, davej@redhat.com, wli@holomorphy.com,
linux-kernel@vger.kernel.org
Subject: Re: dentry bloat.
Date: Sat, 8 May 2004 12:13:09 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.58.0405081208330.3271@ppc970.osdl.org> (raw)
In-Reply-To: <20040508120148.1be96d66.akpm@osdl.org>
On Sat, 8 May 2004, Andrew Morton wrote:
>
> I think we can simply take ->d_lock a bit earlier in __d_lookup. That will
> serialise against d_move(), fixing the problem which you mention, and also
> makes d_movecount go away.
If you do that, RCU basically loses most of it's meaning.
You'll be taking a lock for - and dirtying in the cache - every single
dentry on the hash chain, which is pretty much guaranteed to be slower
than just taking the dcache_lock _once_, even if that one jumps across
CPU's a lot.
In other words, no, I don't think that's a good idea. We really want to
take the dentry lock only after we're pretty sure we have the right
dentry. Otherwise the dentry chains will be bouncing from CPU to CPU all
the time.
Linus
next prev parent reply other threads:[~2004-05-08 19:13 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20040506200027.GC26679@redhat.com>
[not found] ` <20040506150944.126bb409.akpm@osdl.org>
[not found] ` <409B1511.6010500@colorfullife.com>
2004-05-08 8:23 ` Andrew Morton
2004-05-08 9:23 ` Andrew Morton
2004-05-08 10:11 ` Andrew Morton
2004-05-08 10:12 ` Andrew Morton
2004-05-08 10:28 ` viro
2004-05-08 10:41 ` Andrew Morton
2004-05-08 10:52 ` Andrew Morton
2004-05-08 10:31 ` Manfred Spraul
2004-05-08 17:28 ` Linus Torvalds
2004-05-08 18:19 ` David S. Miller
2004-05-08 19:01 ` Andrew Morton
2004-05-08 19:13 ` Linus Torvalds [this message]
2004-05-08 19:27 ` Andrew Morton
2004-05-08 19:27 ` Linus Torvalds
2004-05-08 20:42 ` Dipankar Sarma
2004-05-08 20:55 ` Andrew Morton
2004-05-08 21:19 ` Dipankar Sarma
2004-05-09 0:10 ` Andrew Morton
2004-05-09 2:55 ` Linus Torvalds
2004-05-09 3:12 ` David S. Miller
2004-05-09 3:53 ` Linus Torvalds
2004-05-09 21:03 ` Matt Mackall
2004-05-10 8:27 ` Helge Hafting
2004-05-10 8:32 ` Arjan van de Ven
2004-05-10 9:46 ` Andrew Morton
2004-05-10 14:54 ` Matt Mackall
2004-05-10 16:26 ` Paul E. McKenney
2004-05-10 18:34 ` Dipankar Sarma
2004-05-09 4:12 ` Andrew Morton
2004-05-09 4:25 ` Linus Torvalds
2004-05-09 4:36 ` Andrew Morton
2004-05-09 5:14 ` Linus Torvalds
2004-05-09 7:36 ` Rodolfo Guluarte Hale
2004-05-09 9:10 ` Guennadi Liakhovetski
2004-05-09 9:23 ` viro
2004-05-09 15:35 ` Linus Torvalds
2004-05-09 18:11 ` Matt Mackall
2004-05-09 22:08 ` Francois Romieu
2004-05-09 23:51 ` Paul Jackson
2004-05-10 7:17 ` Florian Weimer
2004-05-10 14:12 ` Rik van Riel
2004-05-09 4:43 ` Linus Torvalds
2004-05-09 7:28 ` Manfred Spraul
2004-05-09 15:33 ` Dipankar Sarma
2004-05-09 22:17 ` viro
2004-05-09 22:27 ` Andrew Morton
2004-05-11 5:26 ` Maneesh Soni
2004-05-10 18:39 ` Dipankar Sarma
2004-05-11 5:17 ` Maneesh Soni
2004-05-08 20:13 ` Dipankar Sarma
2004-10-06 12:58 ` Maneesh Soni
2004-05-11 20:22 ` Andrew Morton
2004-05-14 10:33 ` Raghavan
2004-05-14 10:50 ` Paul Jackson
2004-05-14 11:04 ` Jens Axboe
2004-05-14 11:14 ` Paul Jackson
2004-05-14 11:24 ` Jens Axboe
2004-05-14 11:30 ` Paul Jackson
2004-05-14 11:24 ` Dipankar Sarma
2004-05-14 11:18 ` Dipankar Sarma
2004-05-14 14:44 ` Linus Torvalds
2004-05-08 21:00 ` Dipankar Sarma
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