Re: [patch 2/3] memcg: prevent endless loop when charging huge pagesto near-limit group

From: Minchan Kim
Date: Mon Jan 31 2011 - 17:42:52 EST

On Mon, Jan 31, 2011 at 11:03 PM, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> If reclaim after a failed charging was unsuccessful, the limits are
> checked again, just in case they settled by means of other tasks.
> This is all fine as long as every charge is of size PAGE_SIZE, because
> in that case, being below the limit means having at least PAGE_SIZE
> bytes available.
> But with transparent huge pages, we may end up in an endless loop
> where charging and reclaim fail, but we keep going because the limits
> are not yet exceeded, although not allowing for a huge page.
> Fix this up by explicitely checking for enough room, not just whether
> we are within limits.
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Minchan Kim <>

Kind regards,
Minchan Kim
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