From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx134.postini.com [74.125.245.134]) by kanga.kvack.org (Postfix) with SMTP id 77B1F6B0033 for ; Wed, 19 Jun 2013 20:26:13 -0400 (EDT) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 20 Jun 2013 05:51:15 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp03.in.ibm.com (Postfix) with ESMTP id B4C621258053 for ; Thu, 20 Jun 2013 05:55:04 +0530 (IST) Received: from d28av03.in.ibm.com (d28av03.in.ibm.com [9.184.220.65]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r5K0QCWQ32768026 for ; Thu, 20 Jun 2013 05:56:13 +0530 Received: from d28av03.in.ibm.com (loopback [127.0.0.1]) by d28av03.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r5K0Q4HF026634 for ; Thu, 20 Jun 2013 10:26:05 +1000 Date: Thu, 20 Jun 2013 08:26:03 +0800 From: Wanpeng Li Subject: Re: [PATCH] slub: do not put a slab to cpu partial list when cpu_partial is 0 Message-ID: <20130620002603.GA2640@hacker.(null)> Reply-To: Wanpeng Li References: <1371623635-26575-1-git-send-email-iamjoonsoo.kim@lge.com> <51c1652d.246e320a.4057.ffffed4fSMTPIN_ADDED_BROKEN@mx.google.com> <20130619085250.GC12231@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130619085250.GC12231@lge.com> Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim Cc: Pekka Enberg , Christoph Lameter , Matt Mackall , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Jun 19, 2013 at 05:52:50PM +0900, Joonsoo Kim wrote: >On Wed, Jun 19, 2013 at 04:00:32PM +0800, Wanpeng Li wrote: >> On Wed, Jun 19, 2013 at 03:33:55PM +0900, Joonsoo Kim wrote: >> >In free path, we don't check number of cpu_partial, so one slab can >> >be linked in cpu partial list even if cpu_partial is 0. To prevent this, >> >we should check number of cpu_partial in put_cpu_partial(). >> > >> >> How about skip get_partial entirely? put_cpu_partial is called >> in two paths, one is during refill cpu partial lists in alloc >> slow path, the other is in free slow path. And cpu_partial is 0 >> just in debug mode. >> >> - alloc slow path, there is unnecessary to call get_partial >> since cpu partial lists won't be used in debug mode. >> - free slow patch, new.inuse won't be true in debug mode >> which lead to put_cpu_partial won't be called. >> > >In debug mode, put_cpu_partial() can't be called already on both path. >But, if we assign 0 to cpu_partial via sysfs, put_cpu_partial() will be called >on free slow path. On alloc slow path, it can't be called, because following >test in get_partial_node() is always failed. > >available > s->cpu_partial / 2 Is it always true? We can freeze slab from partial list, and s->cpu_partial is 0. Regards, Wanpeng Li > >Thanks. > >> Regards, >> Wanpeng Li >> >> >Signed-off-by: Joonsoo Kim >> > >> >diff --git a/mm/slub.c b/mm/slub.c >> >index 57707f0..7033b4f 100644 >> >--- a/mm/slub.c >> >+++ b/mm/slub.c >> >@@ -1955,6 +1955,9 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) >> > int pages; >> > int pobjects; >> > >> >+ if (!s->cpu_partial) >> >+ return; >> >+ >> > do { >> > pages = 0; >> > pobjects = 0; >> >-- >> >1.7.9.5 >> > >> >-- >> >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/ . >> >Don't email: email@kvack.org >> >> -- >> 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/ . >> Don't email: email@kvack.org -- 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/ . Don't email: email@kvack.org