From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: [PATCH] tools/libxc: send page-in requests in
 batches in linux_privcmd_map_foreign_bulk
Date: Thu, 26 Jan 2012 17:38:10 +0100
Message-ID: <20120126163810.GA9137@aepfle.de>
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To: Andres Lagar-Cavilla <andres@lagarcavilla.org>
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On Thu, Jan 26, Andres Lagar-Cavilla wrote:

> Olaf,
> if I get a pattern of errors in the err array of the form:
> 
> {ENOENT, EWHATEVER, ENOENT, EWHATEVER}
> with EWHATEVER != ENOENT
> 
> this patch does not optimize anything.

It will poke all gfns instead of a single one before going to sleep.

> Why not alloc a separate arr2 array, move the gfn's that failed with
> ENOENT there, and retry the whole new arr2 block? You only need to
> allocate arr2 once, to size num. That will batch always, everything.

The errors for gfns are most likely fragmented. Merging the gfns means
they will get a different addr. So the overall layout of arr and err
needs to remain the same.

Olaf