From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx151.postini.com [74.125.245.151]) by kanga.kvack.org (Postfix) with SMTP id 93B006B0083 for ; Wed, 12 Dec 2012 16:48:08 -0500 (EST) Message-ID: <50C8FB94.6050209@linux.intel.com> Date: Wed, 12 Dec 2012 13:48:04 -0800 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH v5 09/11] thp: lazy huge zero page allocation References: <1352300463-12627-1-git-send-email-kirill.shutemov@linux.intel.com> <1352300463-12627-10-git-send-email-kirill.shutemov@linux.intel.com> <20121115094155.GG9676@otc-wbsnb-06> <20121212133051.6dad3722.akpm@linux-foundation.org> In-Reply-To: <20121212133051.6dad3722.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Kirill A. Shutemov" , David Rientjes , Andrea Arcangeli , linux-mm@kvack.org, Andi Kleen , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" On 12/12/2012 01:30 PM, Andrew Morton wrote: >> >> I can rewrite the check to static_key if you want. Would it be better? > > The new test-n-branch only happens on the first read fault against a > thp huge page, yes? In which case it's a quite infrequent event and I > suspect this isn't worth bothering about. > Not to mention that flipping the static key is *incredibly* expensive. -hpa -- 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