From: Theodore Ts'o <tytso@mit.edu>
To: Nikolay Borisov <kernel@kyup.com>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] ext4: make use of sb_getblk_gfp
Date: Thu, 2 Jul 2015 10:17:54 -0400 [thread overview]
Message-ID: <20150702141754.GA9456@thunk.org> (raw)
In-Reply-To: <5594D742.6040202@kyup.com>
On Thu, Jul 02, 2015 at 09:16:34AM +0300, Nikolay Borisov wrote:
>
> Just a question that popped to my mind after discussing with a colleague
> - Is GFP_NOFS enough here or should it be GFP_NOIO? Presumably the
> latter is a stronger guarantee that we are not going to hit any
> fs/writeback related code?
GFP_NOFS is fine here; file system code calls the I/O codepaths, but
device driver code doesn't call fs code. Put another way, if there
are pages that are backed by a block device, which can be cleaned
without going through the FS code paths, it's fine to let that happen
while we are inside file system code.
- Ted
next prev parent reply other threads:[~2015-07-02 14:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-30 6:26 [PATCH 1/2] bufferhead: Add _gfp version for sb_getblk() Nikolay Borisov
2015-06-30 6:26 ` [PATCH 2/2] ext4: make use of sb_getblk_gfp Nikolay Borisov
2015-07-02 6:14 ` Theodore Ts'o
2015-07-02 6:16 ` Nikolay Borisov
2015-07-02 14:17 ` Theodore Ts'o [this message]
2015-07-02 6:14 ` [PATCH 1/2] bufferhead: Add _gfp version for sb_getblk() Theodore Ts'o
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