From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id CF3846B002C for ; Tue, 11 Oct 2011 05:47:06 -0400 (EDT) Subject: RE: [PATCH] slub: remove a minus instruction in get_partial_node From: "Alex,Shi" In-Reply-To: References: <1317290716.4188.1227.camel@debian> <6E3BC7F7C9A4BF4286DD4C043110F30B5FD97584A4@shsmsx502.ccr.corp.intel.com> <1318042113.27949.97.camel@debian> Content-Type: text/plain; charset="UTF-8" Date: Tue, 11 Oct 2011 17:50:52 +0800 Message-ID: <1318326652.27949.725.camel@debian> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter Cc: Pekka Enberg , "linux-mm@kvack.org" , "Chen, Tim C" , "Huang, Ying" On Tue, 2011-10-11 at 01:11 +0800, Christoph Lameter wrote: > On Sat, 8 Oct 2011, Alex,Shi wrote: > > > On Mon, 2011-10-03 at 21:55 +0800, Christoph Lameter wrote: > > > On Sun, 2 Oct 2011, Shi, Alex wrote: > > > > > > > > A slab on the partial lists always has objects available. Why would it be > > > > > zero? > > > > > > > > Um, my mistaken. The reason should be: if code is here, the slab will be per cpu slab. > > > > It is no chance to be in per cpu partial and no relationship with per cpu partial. So > > > > no reason to use this value as a criteria for filling per cpu partial. > > > > > > I am not sure I understand you. The point of the code is to count the > > > objects available in the per cpu partial pages so that we can limit the > > > number of pages we fetch from the per node partial list. > > > > Maybe my understanding is incorrect for PCP. :) > > What I thought is: when object == null, the page we got from node > > partial list will be added into cpu slab. It has no chance to become per > > cpu partial page. And it has no relationship with further per cpu > > partial count checking. Since even 'available > cpu_partial/2', it > > doesn't mean per cpu partial objects number > cpu_partial/2. > > acquire_slab should not return NULL unless something seriously goes wrong. > I think we can remove the] > > if (!t) > > statement to avoid futher confusion? That is another story. Wondering if a page freeing by discard_slab impact this or not. I don't fully understand the slub page alloc/free now, may study this later. :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org