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From: Eric Sandeen <sandeen@redhat.com>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dave Jones <davej@redhat.com>,
	"gnehzuil.liu" <gnehzuil.liu@gmail.com>,
	Zheng Liu <wenqing.lz@taobao.com>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] ext4: use percpu counter for extent cache count
Date: Fri, 01 Mar 2013 12:02:34 -0600	[thread overview]
Message-ID: <5130ED3A.30003@redhat.com> (raw)
In-Reply-To: <20130301180035.GB17920@thunk.org>

On 3/1/13 12:00 PM, Theodore Ts'o wrote:
> On Fri, Mar 01, 2013 at 10:42:25AM -0600, Eric Sandeen wrote:
>> Use a percpu counter rather than atomic types for shrinker accounting.
>> There's no need for ultimate accuracy in the shrinker, so this
>> should come a little more cheaply.  The percpu struct is somewhat
>> large, but there was a big gap before the cache-aligned
>> s_es_lru_lock anyway, and it fits nicely in there.
> 
> I thought about using percpu counters, but I was worried about the
> size on really big machines.  OTOH, it will be the really large NUMA
> machines where atomic_t will really hurt, so maybe we should use
> percpu countesr and not really worry about it.  It's on a per file
> system basis, so even if it is a few hundred bytes it shouldn't break
> the bank.
> 
> 						- Ted
> 

I was mostly keying off what quota felt was best, I guess.
I'm not wedded to either approach, it was just a thought.
So you can take it or leave it. :)

Thanks,
-Eric

  reply	other threads:[~2013-03-01 18:02 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-26 20:39 [GIT PULL] ext4 updates for 3.9 Theodore Ts'o
2013-02-27 12:47 ` Markus Trippelsdorf
2013-02-27 15:34   ` Theodore Ts'o
2013-02-27 15:44     ` Markus Trippelsdorf
2013-02-27 17:01       ` Markus Trippelsdorf
2013-02-27 17:10         ` gnehzuil.liu
2013-02-27 17:10           ` gnehzuil.liu
2013-02-27 17:22           ` Markus Trippelsdorf
2013-02-27 17:38             ` gnehzuil.liu
2013-02-27 17:38               ` gnehzuil.liu
2013-02-27 17:45               ` Markus Trippelsdorf
2013-02-27 17:52                 ` Linus Torvalds
2013-02-27 18:49                   ` Theodore Ts'o
2013-02-27 18:56                     ` Markus Trippelsdorf
2013-02-27 19:19                       ` Dave Jones
2013-02-27 19:27                         ` Zheng Liu
2013-02-27 19:29                         ` Theodore Ts'o
2013-02-27 20:12                           ` [GIT PULL URGENT] ext4 regression fix " Linus Torvalds
2013-02-27 20:15                             ` Theodore Ts'o
2013-02-27 20:23                               ` Linus Torvalds
2013-02-27 20:41                                 ` Borislav Petkov
2013-03-01  3:30                             ` Dave Jones
2013-03-01  4:00                               ` Theodore Ts'o
2013-03-01  5:00                                 ` [PATCH] ext4: optimize ext4_es_shrink() Theodore Ts'o
2013-03-01 16:11                                   ` Dave Jones
2013-03-01 16:26                                     ` Theodore Ts'o
2013-03-01 16:40                                       ` Dave Jones
2013-03-01 16:40                                   ` Eric Sandeen
2013-03-01 16:42                                   ` [PATCH] ext4: use percpu counter for extent cache count Eric Sandeen
2013-03-01 18:00                                     ` Theodore Ts'o
2013-03-01 18:02                                       ` Eric Sandeen [this message]
2013-03-02 15:26                                         ` Theodore Ts'o
2013-03-03 16:39                                           ` Zheng Liu
2013-03-04 16:11                                           ` Eric Sandeen
2013-03-02 19:54                                 ` [GIT PULL URGENT] ext4 regression fix for 3.9 Linus Torvalds
2013-03-02 23:15                                   ` Theodore Ts'o
2013-02-27 20:14                           ` Theodore Ts'o
2013-02-27 20:58                           ` [GIT PULL] ext4 updates " Dmitry Monakhov
2013-02-27 21:30                             ` Theodore Ts'o
2013-03-01 15:41                             ` Eric Sandeen
2013-02-28 13:18                           ` Dave Chinner
2013-02-27 18:57                     ` Dave Jones
2013-02-27 19:04                       ` Theodore Ts'o
2013-02-27 19:11                         ` Dave Jones
2013-02-27 19:19                           ` Theodore Ts'o
2013-02-27 18:59                     ` Zheng Liu
2013-02-27 19:06                     ` Borislav Petkov

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