On Fri, Feb 10, 2017 at 06:23:35PM +0100, Vlastimil Babka wrote: > When detecting whether compaction has succeeded in forming a high-order page, > __compact_finished() employs a watermark check, followed by an own search for > a suitable page in the freelists. This is not ideal for two reasons: > > - The watermark check also searches high-order freelists, but has a less > strict > criteria wrt fallback. It's therefore redundant and waste of cycles. This > was > different in the past when high-order watermark check attempted to apply > reserves to high-order pages. > > - The watermark check might actually fail due to lack of order-0 pages. > Compaction can't help with that, so there's no point in continuing because > of > that. It's possible that high-order page still exists and it terminates. > > This patch therefore removes the watermark check. This should save some cycles > and terminate compaction sooner in some cases. > > Signed-off-by: Vlastimil Babka <vba...@suse.cz>
Acked-by: Johannes Weiner <han...@cmpxchg.org>
