Re: [PATCH] xen: Fix selfballooning and ensure it doesn't go too far

From: Konrad Rzeszutek Wilk
Date: Mon Sep 26 2011 - 13:23:32 EST


On Sat, Sep 24, 2011 at 01:58:08PM -0700, Dan Magenheimer wrote:
> [PATCH] xen: Fix selfballooning and ensure it doesn't go too far
>
> The balloon driver's "current_pages" is very different from
> totalram_pages. Self-ballooning needs to be driven by
> the latter. Also, Committed_AS doesn't account for pages
> used by the kernel so enforce a floor for when there
> are little or no user-space threads using memory.

Hey Dan,
..
> + floor_pages = totalreserve_pages +
> + (roundup_pow_of_two(max_pfn) >> 5);

Would it make sense to make the shift be a runtime argument
in case some users report problems with that calculation?

> + /* don't balloon too far, lest OOMs occur... */
> + if (tgt_pages < floor_pages)
> + tgt_pages = floor_pages;
> + balloon_set_new_target(tgt_pages +
> + balloon_stats.current_pages - totalram_pages);
> reset_timer = true;
> }
> #ifdef CONFIG_FRONTSWAP

Otherwise it looks OK to me. Would you like me to queue it up
for 3.1-rc7?
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