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From: Christoph Hellwig <hch@infradead.org>
To: Bryan Donlan <bdonlan@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	John Stultz <john.stultz@linaro.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Robert Love <rlove@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>, Mel Gorman <mel@csn.ul.ie>,
	Dave Hansen <dave@linux.vnet.ibm.com>,
	Rik van Riel <riel@redhat.com>, Eric Anholt <eric@anholt.net>,
	Jesse Barnes <jbarnes@virtuousgeek.org>
Subject: Re: [RFC][PATCH] Anonymous shared memory (ashmem) subsystem
Date: Mon, 18 Jul 2011 23:36:02 -0400	[thread overview]
Message-ID: <20110719033602.GA4867@infradead.org> (raw)
In-Reply-To: <CAF_S4t_oOwsuPJdMXv+wPVhzecUag=TOWj1-KtFJqYUZOCBbog@mail.gmail.com>

On Mon, Jul 18, 2011 at 11:32:42PM -0400, Bryan Donlan wrote:
> The pinning stuff seems like a reasonable idea to me, but why should
> it be limited to ashmem using a private ioctl? If it were a proper
> syscall, I could see automatic discarding being useful in on-disk
> filesystems as well, for managing persistent caches.

Exactly.

> But yes, tmpfs
> already solved the problem of getting a shared-memory file descriptor
> - just open a random-name file in tmpfs, unlink it, and start passing
> it around.

Indeed.  And as mentioned before using /dev/zero as the file will
get you a pre-unlinked tmpfs fd without any races, and without the
need of actually mounting shmem into any namespace.

  reply	other threads:[~2011-07-19  3:36 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-18 18:54 [RFC][PATCH] Anonymous shared memory (ashmem) subsystem John Stultz
2011-07-19  2:19 ` Christoph Hellwig
2011-07-19  3:32   ` Bryan Donlan
2011-07-19  3:36     ` Christoph Hellwig [this message]
2011-07-19 15:37       ` Dave Hansen
2011-07-19 15:41         ` Christoph Hellwig
2011-07-19 21:58           ` John Stultz
2011-07-19 14:33 ` Christoph Lameter
2011-07-19 15:55 ` Arnd Bergmann

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