From: Olaf Hering <olaf@aepfle.de>
To: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Cc: xen-devel@lists.xensource.com
Subject: Re: [PATCH 2 of 4] xenpaging: use wait queues
Date: Fri, 2 Dec 2011 17:43:57 +0100 [thread overview]
Message-ID: <20111202164357.GA29226@aepfle.de> (raw)
In-Reply-To: <fa38d847359784f92a266c98b7855924.squirrel@webmail.lagarcavilla.org>
On Fri, Dec 02, Andres Lagar-Cavilla wrote:
> > The pager is in the process of writing the gfn to disk after successful
> > nomination. Its next step is the eviction, which will now fail because
> > the p2mt is not p2m_ram_paging_out anymore. It is already prepared for
> > that failure.
> > The previous MEM_EVENT_FLAG_EVICT_FAIL was not needed in the first
> > place.
> Yes it was! The biggest source of overhead is I/O. Tell the pager to stop
> I/O early. Otherwise, you've done the paging out I/O pointlessly, to find
> out only when you try to finalize the eviction.
I'm not sure how to inform the pager, its most likely in the middle of
write(). Since such an event is rare (in my testing at least) I wonder
wether its worth to make it complicated?
Olaf
next prev parent reply other threads:[~2011-12-02 16:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.3014.1322742146.12970.xen-devel@lists.xensource.com>
2011-12-01 15:17 ` [PATCH 2 of 4] xenpaging: use wait queues Andres Lagar-Cavilla
2011-12-01 18:46 ` Olaf Hering
2011-12-01 20:02 ` Andres Lagar-Cavilla
2011-12-02 16:30 ` Andres Lagar-Cavilla
2011-12-02 16:43 ` Olaf Hering [this message]
2011-12-02 17:23 ` Andres Lagar-Cavilla
2011-12-02 17:34 ` Olaf Hering
2011-12-01 11:09 [PATCH 0 of 4] RFC: wait queue usage Olaf Hering
2011-12-01 11:09 ` [PATCH 2 of 4] xenpaging: use wait queues Olaf Hering
2011-12-15 12:28 ` Tim Deegan
2011-12-15 12:40 ` Olaf Hering
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