From: Avi Kivity <avi@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Chris Webb <chris@arachsys.com>,
balbir@linux.vnet.ibm.com,
KVM development list <kvm@vger.kernel.org>,
Rik van Riel <riel@surriel.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kevin Wolf <kwolf@redhat.com>
Subject: Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter
Date: Wed, 17 Mar 2010 19:03:34 +0200 [thread overview]
Message-ID: <4BA10B66.1020705@redhat.com> (raw)
In-Reply-To: <20100317165854.GC29548@lst.de>
On 03/17/2010 06:58 PM, Christoph Hellwig wrote:
> On Wed, Mar 17, 2010 at 06:53:34PM +0200, Avi Kivity wrote:
>
>> Meanwhile I looked at the code, and it looks bad. There is an
>> IO_CMD_FDSYNC, but it isn't tagged, so we have to drain the queue before
>> issuing it. In any case, qemu doesn't use it as far as I could tell,
>> and even if it did, device-matter doesn't implement the needed
>> ->aio_fsync() operation.
>>
> No one implements it, and all surrounding code is dead wood. It would
> require us to do asynchronous pagecache operations, which involve
> major surgery of the VM code. Patches to do this were rejected multiple
> times.
>
Pity. What about the O_DIRECT aio case? It's ridiculous that you can
submit async write requests but have to wait synchronously for them to
actually hit the disk if you have a write cache.
--
error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Chris Webb <chris@arachsys.com>,
balbir@linux.vnet.ibm.com,
KVM development list <kvm@vger.kernel.org>,
Rik van Riel <riel@surriel.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kevin Wolf <kwolf@redhat.com>
Subject: Re: [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter
Date: Wed, 17 Mar 2010 19:03:34 +0200 [thread overview]
Message-ID: <4BA10B66.1020705@redhat.com> (raw)
In-Reply-To: <20100317165854.GC29548@lst.de>
On 03/17/2010 06:58 PM, Christoph Hellwig wrote:
> On Wed, Mar 17, 2010 at 06:53:34PM +0200, Avi Kivity wrote:
>
>> Meanwhile I looked at the code, and it looks bad. There is an
>> IO_CMD_FDSYNC, but it isn't tagged, so we have to drain the queue before
>> issuing it. In any case, qemu doesn't use it as far as I could tell,
>> and even if it did, device-matter doesn't implement the needed
>> ->aio_fsync() operation.
>>
> No one implements it, and all surrounding code is dead wood. It would
> require us to do asynchronous pagecache operations, which involve
> major surgery of the VM code. Patches to do this were rejected multiple
> times.
>
Pity. What about the O_DIRECT aio case? It's ridiculous that you can
submit async write requests but have to wait synchronously for them to
actually hit the disk if you have a write cache.
--
error compiling committee.c: too many arguments to function
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-03-17 17:05 UTC|newest]
Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-15 7:22 [PATCH][RF C/T/D] Unmapped page cache control - via boot parameter Balbir Singh
2010-03-15 7:22 ` Balbir Singh
2010-03-15 7:48 ` Avi Kivity
2010-03-15 7:48 ` Avi Kivity
2010-03-15 8:07 ` Balbir Singh
2010-03-15 8:07 ` Balbir Singh
2010-03-15 8:27 ` Avi Kivity
2010-03-15 8:27 ` Avi Kivity
2010-03-15 9:17 ` Balbir Singh
2010-03-15 9:17 ` Balbir Singh
2010-03-15 9:27 ` Avi Kivity
2010-03-15 9:27 ` Avi Kivity
2010-03-15 10:45 ` Balbir Singh
2010-03-15 10:45 ` Balbir Singh
2010-03-15 18:48 ` Anthony Liguori
2010-03-15 18:48 ` Anthony Liguori
2010-03-16 9:05 ` Avi Kivity
2010-03-16 9:05 ` Avi Kivity
2010-03-19 7:23 ` Dave Hansen
2010-03-19 7:23 ` Dave Hansen
2010-03-15 20:23 ` Chris Webb
2010-03-15 20:23 ` Chris Webb
2010-03-15 23:43 ` Anthony Liguori
2010-03-15 23:43 ` Anthony Liguori
2010-03-16 0:43 ` Christoph Hellwig
2010-03-16 0:43 ` Christoph Hellwig
2010-03-16 1:27 ` Anthony Liguori
2010-03-16 1:27 ` Anthony Liguori
2010-03-16 8:19 ` Christoph Hellwig
2010-03-16 8:19 ` Christoph Hellwig
2010-03-17 15:14 ` Chris Webb
2010-03-17 15:14 ` Chris Webb
2010-03-17 15:55 ` Anthony Liguori
2010-03-17 15:55 ` Anthony Liguori
2010-03-17 16:27 ` Chris Webb
2010-03-17 16:27 ` Chris Webb
2010-03-22 21:04 ` Chris Webb
2010-03-22 21:04 ` Chris Webb
2010-03-22 21:07 ` Avi Kivity
2010-03-22 21:07 ` Avi Kivity
2010-03-22 21:10 ` Chris Webb
2010-03-22 21:10 ` Chris Webb
2010-03-17 16:27 ` Balbir Singh
2010-03-17 16:27 ` Balbir Singh
2010-03-17 17:05 ` Vivek Goyal
2010-03-17 17:05 ` Vivek Goyal
2010-03-17 19:11 ` Chris Webb
2010-03-17 19:11 ` Chris Webb
2010-03-16 3:16 ` Balbir Singh
2010-03-16 3:16 ` Balbir Singh
2010-03-16 9:17 ` Avi Kivity
2010-03-16 9:17 ` Avi Kivity
2010-03-16 9:54 ` Kevin Wolf
2010-03-16 9:54 ` Kevin Wolf
2010-03-16 10:16 ` Avi Kivity
2010-03-16 10:16 ` Avi Kivity
2010-03-16 10:26 ` Christoph Hellwig
2010-03-16 10:26 ` Christoph Hellwig
2010-03-16 10:36 ` Avi Kivity
2010-03-16 10:36 ` Avi Kivity
2010-03-16 10:44 ` Christoph Hellwig
2010-03-16 10:44 ` Christoph Hellwig
2010-03-16 11:08 ` Avi Kivity
2010-03-16 11:08 ` Avi Kivity
2010-03-16 14:27 ` Balbir Singh
2010-03-16 14:27 ` Balbir Singh
2010-03-16 15:59 ` Avi Kivity
2010-03-16 15:59 ` Avi Kivity
2010-03-17 8:49 ` Christoph Hellwig
2010-03-17 8:49 ` Christoph Hellwig
2010-03-17 9:10 ` Avi Kivity
2010-03-17 9:10 ` Avi Kivity
2010-03-17 15:24 ` Chris Webb
2010-03-17 15:24 ` Chris Webb
2010-03-17 16:22 ` Avi Kivity
2010-03-17 16:22 ` Avi Kivity
2010-03-17 16:40 ` Avi Kivity
2010-03-17 16:40 ` Avi Kivity
2010-03-17 16:47 ` Chris Webb
2010-03-17 16:47 ` Chris Webb
2010-03-17 16:53 ` Avi Kivity
2010-03-17 16:53 ` Avi Kivity
2010-03-17 16:58 ` Christoph Hellwig
2010-03-17 16:58 ` Christoph Hellwig
2010-03-17 17:03 ` Avi Kivity [this message]
2010-03-17 17:03 ` Avi Kivity
2010-03-17 16:57 ` Christoph Hellwig
2010-03-17 16:57 ` Christoph Hellwig
2010-03-17 17:06 ` Avi Kivity
2010-03-17 17:06 ` Avi Kivity
2010-03-17 16:52 ` Christoph Hellwig
2010-03-17 16:52 ` Christoph Hellwig
2010-03-17 17:02 ` Avi Kivity
2010-03-17 17:02 ` Avi Kivity
2010-03-15 15:46 ` Randy Dunlap
2010-03-15 15:46 ` Randy Dunlap
2010-03-16 3:21 ` Balbir Singh
2010-03-16 3:21 ` Balbir Singh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4BA10B66.1020705@redhat.com \
--to=avi@redhat.com \
--cc=balbir@linux.vnet.ibm.com \
--cc=chris@arachsys.com \
--cc=hch@lst.de \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=kvm@vger.kernel.org \
--cc=kwolf@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=riel@surriel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.