From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f47.google.com (mail-la0-f47.google.com [209.85.215.47]) by kanga.kvack.org (Postfix) with ESMTP id 16F006B00CC for ; Tue, 19 May 2015 11:24:32 -0400 (EDT) Received: by lagr1 with SMTP id r1so29551133lag.0 for ; Tue, 19 May 2015 08:24:31 -0700 (PDT) Received: from mail-wg0-x232.google.com (mail-wg0-x232.google.com. [2a00:1450:400c:c00::232]) by mx.google.com with ESMTPS id e5si5085219wix.88.2015.05.19.08.24.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 19 May 2015 08:24:29 -0700 (PDT) Received: by wgjc11 with SMTP id c11so22246098wgj.0 for ; Tue, 19 May 2015 08:24:29 -0700 (PDT) Date: Tue, 19 May 2015 17:27:10 +0200 From: Michal Hocko Subject: Re: [PATCH] mm, memcg: Optionally disable memcg by default using Kconfig Message-ID: <20150519152710.GK6203@dhcp22.suse.cz> References: <20150519104057.GC2462@suse.de> <20150519141807.GA9788@cmpxchg.org> <20150519145340.GI6203@dhcp22.suse.cz> <20150519151302.GG2462@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150519151302.GG2462@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Tejun Heo , cgroups@vger.kernel.org On Tue 19-05-15 16:13:02, Mel Gorman wrote: [...] > :ffffffff811c160f: je ffffffff811c1630 > :ffffffff811c1611: xor %eax,%eax > :ffffffff811c1613: xor %ebx,%ebx > 1 1.7e-05 :ffffffff811c1615: mov %rbx,(%r12) > 7 1.2e-04 :ffffffff811c1619: add $0x10,%rsp > 1211 0.0203 :ffffffff811c161d: pop %rbx > 5 8.4e-05 :ffffffff811c161e: pop %r12 > 5 8.4e-05 :ffffffff811c1620: pop %r13 > 1249 0.0210 :ffffffff811c1622: pop %r14 > 7 1.2e-04 :ffffffff811c1624: pop %rbp > 5 8.4e-05 :ffffffff811c1625: retq > :ffffffff811c1626: nopw %cs:0x0(%rax,%rax,1) > 295 0.0050 :ffffffff811c1630: mov (%rdi),%rax > 160703 2.6973 :ffffffff811c1633: mov %edx,%r13d Huh, what? Even if this was off by one and the preceding instruction has consumed the time. This would be reading from page->flags but the page should be hot by the time we got here, no? > #### MEL: I was surprised to see this atrocity. It's a PageSwapCache check > #### /usr/src/linux-4.0-vanilla/./arch/x86/include/asm/bitops.h:311 > #### /usr/src/linux-4.0-vanilla/include/linux/page-flags.h:261 > #### /usr/src/linux-4.0-vanilla/mm/memcontrol.c:5473 -- Michal Hocko SUSE Labs -- 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