From: Theodore Ts'o <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: Zheng Liu <gnehzuil.liu@gmail.com>,
linux-ext4@vger.kernel.org,
Andreas Dilger <adilger.kernel@dilger.ca>,
Zheng Liu <wenqing.lz@taobao.com>
Subject: Re: [PATCH v3 4/6] ext4: change lru to round-robin in extent status tree shrinker
Date: Wed, 3 Sep 2014 18:38:05 -0400 [thread overview]
Message-ID: <20140903223805.GD12154@thunk.org> (raw)
In-Reply-To: <20140903221402.GD19005@quack.suse.cz>
On Thu, Sep 04, 2014 at 12:14:02AM +0200, Jan Kara wrote:
> > I didn't think we were allowed to reschedule or sleep while in
> > shrinker context?
> I believe we are allowed to sleep in the shrinker if appropriate gfp
> flags are set (__GFP_WAIT) and we enter extent cache shrinker only if
> __GFP_FS is set which guarantees __GFP_WAIT.
I must be missing something. How is this guaranteed?
I can see how we can determine what gfp_mask was used in the
allocation which triggered the shrinker callback, by checking
shrink->gfp_mask, but I don't see anything that guarantees that the
extent cache shrinker is only entered if __GFP_FS is set.
I guess we could add something like:
if ((shrink->gfp_mask & __GFP_WAIT) == 0)
return 0;
to the beginning of ext4_es_scan(), but we're not doing that at the
moment.
- Ted
next prev parent reply other threads:[~2014-09-03 22:38 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-07 3:35 [PATCH v3 0/6] ext4: extents status tree shrinker improvement Zheng Liu
2014-08-07 3:35 ` [PATCH v3 1/6] ext4: improve extents status tree trace point Zheng Liu
2014-09-02 2:25 ` Theodore Ts'o
2014-08-07 3:35 ` [PATCH v3 2/6] ext4: track extent status tree shrinker delay statictics Zheng Liu
2014-08-27 13:26 ` Jan Kara
2014-09-04 12:10 ` Zheng Liu
2014-09-04 15:49 ` Theodore Ts'o
2014-08-07 3:35 ` [PATCH v3 3/6] ext4: cache extent hole in extent status tree for ext4_da_map_blocks() Zheng Liu
2014-08-27 13:55 ` Jan Kara
2014-09-04 13:05 ` Zheng Liu
2014-09-02 2:43 ` Theodore Ts'o
2014-09-04 13:04 ` Zheng Liu
2014-09-04 15:54 ` Theodore Ts'o
2014-08-07 3:35 ` [PATCH v3 4/6] ext4: change lru to round-robin in extent status tree shrinker Zheng Liu
2014-08-27 15:01 ` Jan Kara
2014-09-03 3:37 ` Theodore Ts'o
2014-09-03 15:31 ` Jan Kara
2014-09-03 20:00 ` Theodore Ts'o
2014-09-03 22:14 ` Jan Kara
2014-09-03 22:38 ` Theodore Ts'o [this message]
[not found] ` <20140904071553.GA26930@quack.suse.cz>
2014-09-04 15:44 ` Theodore Ts'o
2014-09-08 15:47 ` Jan Kara
2014-08-07 3:35 ` [PATCH v3 5/6] ext4: use a list to track all reclaimable objects for extent status tree Zheng Liu
2014-08-27 15:13 ` Jan Kara
2014-09-03 3:44 ` Theodore Ts'o
2014-08-07 3:35 ` [PATCH v3 6/6] ext4: use a garbage collection algorithm to manage object Zheng Liu
2014-08-27 15:24 ` Jan Kara
2014-10-20 14:48 ` [PATCH v3 0/6] ext4: extents status tree shrinker improvement Theodore Ts'o
2014-10-21 10:22 ` Jan Kara
2014-10-21 15:58 ` 刘峥(文卿)
2014-11-03 16:10 ` Jan Kara
2014-11-07 2:38 ` Zheng Liu
2014-11-13 23:40 ` Theodore Ts'o
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