From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH] mm, memcg: Optionally disable memcg by default using Kconfig Date: Tue, 19 May 2015 17:27:10 +0200 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 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=0XFCfKCQ3D413YOVd6woWJ3H7TLUL2F5ffifKbg9tgc=; b=qEsknwncTB2neI5Pa1o4gvx/w/isKiFpRUjJHeQYJvMh4d7z9u47fJDOWBxL84Sppx eQRZO3LxozXp9DK0sjdZIykdk3mYJ5YA/30uR/7d2vgmdOnsReYbjoy1yA65LgN4NFmL ADN6JOE8fAVbWpRJQFzLkbqT6OxsePOMA9aztZ5js+QyKwbf89AVM+MS73j5EAO9rRM6 /3WJHkOSjHBahBn4p750C/62OAlCzMWme1UhNvcXwNzgkK9Z0syhi75ThMEjfYHPBQVo n70vBRhAXJfBrmvprd9fNISQwgtgQwmKzh8qKbS/0GkV4dPDvIfvFD0jrWed5mCngVhO swVg== Content-Disposition: inline In-Reply-To: <20150519151302.GG2462@suse.de> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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