Messages in this thread | | | Date | Tue, 19 Jun 2012 09:02:01 +0900 | From | Kamezawa Hiroyuki <> | Subject | Re: [PATCH] mm/memcg: add unlikely to mercg->move_charge_at_immigrate |
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(2012/06/18 22:19), Wanpeng Li wrote: > On Mon, Jun 18, 2012 at 05:09:36PM +0400, Glauber Costa wrote: >> On 06/18/2012 05:10 PM, Wanpeng Li wrote: >>> From: Wanpeng Li<liwp@linux.vnet.ibm.com> >>> >>> move_charge_at_immigrate feature is disabled by default. Charges >>> are moved only when you move mm->owner and it also add additional >>> overhead. >> >> How big is this overhead? >> >> That's hardly a fast path. And if it happens to matter, it will be >> just bigger when you enable it, and the compiler start giving the >> wrong hints to the code. > > Thank you for your quick response. > > Oh, Maybe I should just write comments "move_charge_at_immigrate feature > is disabled by default. So add "unlikely", in order to compiler can optimize." >
This doesn't affect the performance. likely/unlikely which doesn't affect performance is never welcomed.
Thanks, -Kame
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