Re: [PATCH] mm/swap: add independed bio pool for swap

From: Konstantin Khlebnikov
Date: Thu Dec 20 2012 - 04:29:38 EST


Andrew Morton wrote:
On Mon, 17 Dec 2012 20:45:13 -0800 (PST)
Hugh Dickins<hughd@xxxxxxxxxx> wrote:

On Fri, 14 Dec 2012, Konstantin Khlebnikov wrote:

This bio pool guarantees reclaiming progress for anonymous pages.
All avaliable bio in fs_bio_set may be borrowed by writeback which may
never ends, because disk too slow or broken. I have seen this situation in
real life in system where was a lot of bio requests to a loop device which
laying on top of special fuse-based filesystem.

Hmm, perhaps, I'm not at all sure.

It probably maybe perhaps makes sense. Of course, you're screwed if
one of your swap devices is "disk too slow or broken".

My crystal ball tells me that the 2015 kernel will have a bioset per
physical device...


I predict that they also will be per-cpu. Well... probably maybe we should
just wait for this shining future. I leave this to your discretion...
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