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From: Jim Meyering <jim@meyering.net>
To: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>,
	Jaegeuk Hanse <jaegeuk.hanse@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Theodore Ts'o <tytso@mit.edu>, Zheng Liu <wenqing.lz@taobao.com>,
	Jeff liu <jeff.liu@oracle.com>, Paul Eggert <eggert@cs.ucla.edu>,
	Christoph Hellwig <hch@infradead.org>,
	Josef Bacik <josef@redhat.com>, Andi Kleen <andi@firstfloor.org>,
	Andreas Dilger <adilger@dilger.ca>,
	Marco Stornelli <marco.stornelli@gmail.com>,
	Chris Mason <chris.mason@fusionio.com>,
	Sunil Mushran <sunil.mushran@oracle.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] tmpfs: support SEEK_DATA and SEEK_HOLE (reprise)
Date: Thu, 29 Nov 2012 21:17:51 +0100	[thread overview]
Message-ID: <87ip8o17v4.fsf@rho.meyering.net> (raw)
In-Reply-To: <20121129195206.GB6434@dastard> (Dave Chinner's message of "Fri, 30 Nov 2012 06:52:07 +1100")

Dave Chinner wrote:
...
>> So, yes, GNU cp will soon use this feature.
>
> It would be nice if utilities like grep used it, too, because having
> grep burn gigabytes of memory scanning holes in large files and
> then going OOM is, well, kind of nasty:
>
> $ xfs_io -f -c "truncate 1t" blah
> $ ls -l
> total 0
> -rw-r--r-- 1 dave dave 1.0T Nov 30 06:42 blah
> $ grep foo blah
> grep: memory exhausted
> $ $ grep -V
> grep (GNU grep) 2.12

Hi Dave,

Yes, adapting grep is also on the road map.
That precise case was one of my arguments for making SEEK_DATA/SEEK_HOLE
support more widespread.

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  reply	other threads:[~2012-11-29 20:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-29  1:22 Hugh Dickins
2012-11-29  1:29 ` Jaegeuk Hanse
2012-11-29  2:02   ` Hugh Dickins
2012-11-29  4:15     ` Jim Meyering
2012-11-29  4:42       ` Jeff Liu
2012-11-29  6:53         ` Jim Meyering
2012-11-29  7:27           ` Jeff Liu
2012-11-29 19:52       ` Dave Chinner
2012-11-29 20:17         ` Jim Meyering [this message]
2012-11-29  2:44 ` Dave Chinner
2012-11-29  4:22   ` Hugh Dickins
2012-11-29 22:59 ` Andrew Morton
2012-11-29 23:29   ` Hugh Dickins
2012-11-30  0:18     ` Andrew Morton

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