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From: Christoph Hellwig <hch@infradead.org>
To: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 3/14] tmpfs: take control of its truncate_range
Date: Fri, 3 Jun 2011 01:16:09 -0400	[thread overview]
Message-ID: <20110603051609.GC16721@infradead.org> (raw)
In-Reply-To: <alpine.LSU.2.00.1106010940590.23468@sister.anvils>

On Wed, Jun 01, 2011 at 09:58:18AM -0700, Hugh Dickins wrote:
> (i915 isn't really doing hole-punching there, I think it just found it
> a useful interface to remove the page-and-swapcache without touching
> i_size.  Parentheses because it makes no difference to your point.)

Keeping i_size while removing pages on tmpfs fits the defintion of hole
punching for me.  Not that it matters anyway.

> When I say "shmem", I am including the !SHMEM-was-TINY_SHMEM case too,
> which goes to ramfs.  Currently i915 has been configured to disable that
> possibility, though we insisted on it originally: there may or may not be
> good reason for disabling it - may just be a side-effect of the rather
> twisted unintuitive SHMEM/TMPFS dependencies.

Hmm, the two different implementations make everything harder.  Also
because we don't even implement the hole punching in !SHMEM tmpfs.

> Fine, I'll add tmpfs PUNCH_HOLE later on.  And wire up madvise MADV_REMOVE
> to fallocate PUNCH_HOLE, yes?

Yeah.  One thing I've noticed is that the hole punching doesn't seem
to do the unmap_mapping_range.  It might be worth to audit that from the
VM point of view.

> Would you like me to remove the ->truncate_range method from
> inode_operations completely?

Doing that would be nice.  Do we always have the required file struct
for ->fallocate in the callers?

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  reply	other threads:[~2011-06-03  5:16 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-31  0:33 [PATCH 0/14] mm: tmpfs and trunc changes, affecting drm Hugh Dickins
2011-05-31  0:35 ` [PATCH 1/14] mm: invalidate_mapping_pages flush cleancache Hugh Dickins
2011-05-31 15:49   ` Dan Magenheimer
2011-05-31 17:05     ` Hugh Dickins
2011-05-31 21:08       ` Chris Mason
2011-05-31 22:01         ` Hugh Dickins
2011-05-31  0:36 ` [PATCH 2/14] mm: move vmtruncate_range to truncate.c Hugh Dickins
2011-06-01  0:36   ` Christoph Hellwig
2011-05-31  0:39 ` [PATCH 3/14] tmpfs: take control of its truncate_range Hugh Dickins
2011-06-01  0:39   ` Christoph Hellwig
2011-06-01 16:58     ` Hugh Dickins
2011-06-03  5:16       ` Christoph Hellwig [this message]
2011-06-06  5:37         ` Hugh Dickins
2011-05-31  0:40 ` [PATCH 4/14] tmpfs: add shmem_read_mapping_page_gfp Hugh Dickins
2011-06-01  0:42   ` Christoph Hellwig
2011-06-01 17:02     ` Hugh Dickins
2011-05-31  0:42 ` [PATCH 5/14] drm/ttm: use shmem_read_mapping_page Hugh Dickins
2011-05-31  0:43 ` [PATCH 6/14] drm/i915: " Hugh Dickins
2011-05-31  0:45 ` [PATCH 7/14] drm/i915: adjust to new truncate_range Hugh Dickins
2011-06-01  0:43   ` Christoph Hellwig
2011-06-01 17:04     ` Hugh Dickins
2011-05-31  0:46 ` [PATCH 8/14] drm/i915: more struct_mutex locking Hugh Dickins
2011-05-31  0:48 ` [PATCH 9/14] mm: cleanup descriptions of filler arg Hugh Dickins
2011-05-31  0:49 ` [PATCH 10/14] mm: truncate functions are in truncate.c Hugh Dickins
2011-05-31  0:51 ` [PATCH 11/14] mm: tidy vmtruncate_range and related functions Hugh Dickins
2011-05-31  0:52 ` [PATCH 12/14] mm: consistent truncate and invalidate loops Hugh Dickins
2011-05-31  0:54 ` [PATCH 13/14] mm: pincer in truncate_inode_pages_range Hugh Dickins
2011-05-31  0:55 ` [PATCH 14/14] tmpfs: no need to use i_lock Hugh Dickins
2011-05-31 16:08   ` Tim Chen
2011-06-06  4:21 [PATCH 0/14] mm: tmpfs and trunc changes, affecting drm Hugh Dickins
2011-06-06  4:26 ` [PATCH 3/14] tmpfs: take control of its truncate_range Hugh Dickins

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