From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Al Viro <viro@ZenIV.linux.org.uk>, linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Dave Chinner <david@fromorbit.com>,
Ming Lei <ming.lei@canonical.com>
Subject: Re: __vmalloc() vs. GFP_NOIO/GFP_NOFS
Date: Mon, 4 Jan 2016 22:40:51 +0900 [thread overview]
Message-ID: <568A7663.80407@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20160103071246.GK9938@ZenIV.linux.org.uk>
On 2016/01/03 16:12, Al Viro wrote:
> Those, AFAICS, are such callers with GFP_NOIO; however, there's a shitload
> of GFP_NOFS ones. XFS uses memalloc_noio_save(), but a _lot_ of other
> callers do not. For example, all call chains leading to ceph_kvmalloc()
> pass GFP_NOFS and none of them is under memalloc_noio_save(). The same
> goes for GFS2 __vmalloc() callers, etc. Again, quite a few of those probably
> do not need GFP_NOFS at all, but those that do would appear to have
> hard-to-trigger deadlocks.
>
> Why do we do that in callers, though? I.e. why not do something like this:
This problem is not specific to vmalloc(). It is difficult for
non-fs developers to determine whether they need to use GFP_NOFS than
GFP_KERNEL in their code. Can't we annotate GFP_NOFS/GFP_NOIO sections like
http://marc.info/?l=linux-mm&m=142797559822655 ?
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prev parent reply other threads:[~2016-01-04 13:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-03 7:12 __vmalloc() vs. GFP_NOIO/GFP_NOFS Al Viro
2016-01-03 16:56 ` Al Viro
2016-01-03 20:12 ` Dave Chinner
2016-01-03 20:35 ` Al Viro
2016-01-05 15:35 ` Michal Hocko
2016-01-04 13:40 ` Tetsuo Handa [this message]
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