From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 22 Jul 2015 17:45:41 +0200 (CEST) Received: from mail-wi0-f175.google.com ([209.85.212.175]:36468 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27010910AbbGVPpjZQF-z (ORCPT ); Wed, 22 Jul 2015 17:45:39 +0200 Received: by wicgb10 with SMTP id gb10so104223621wic.1 for ; Wed, 22 Jul 2015 08:45:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=WLHDMHnJdQkSrrpd1QnXE09wE6ziRH15y/IHBOOlPv4=; b=dPlPrporY1hdLBRS/LFS1IuQ0Vqa8RMf8V3C1w9fLLKdQwqRWn/SM8GP9wcU+sw0/E 6HTt3FhQKlV4O6F2OGZDxQghPmoMZ3lxQ0Ysb+FfPYIlUkL/rGB50UAzNdtEiN/hzW57 vBg0lI0ZD+pIxVCpUpq7lvbTV6/BWBkpnZOrqrIq4Lo77icXYswPOXVzWrlonroJj8Xs p35ehqM/2ngP9zlElEqMDwCvbLAYRnIMYxiK4EiboGedkMDu76+bx7tedaQIqSFPE5XZ sEJvkPJr4wVHWGN0JF1MIaH+cm7rwyzpVCe9/NFZ+RWuhScAoDg01Tbr92VEgvvzHLNR gs6w== X-Gm-Message-State: ALoCoQlzLhyZ5/OpVW7YE15H8f7HFus12EnNRzyHsHv/Ndts8Qp0mez0cZ2sOG/o94lgGuqP/zkv X-Received: by 10.194.89.5 with SMTP id bk5mr6579089wjb.144.1437579933189; Wed, 22 Jul 2015 08:45:33 -0700 (PDT) Received: from node.shutemov.name (dsl-espbrasgw1-54f9d1-241.dhcp.inet.fi. [84.249.209.241]) by smtp.gmail.com with ESMTPSA id n6sm4016496wix.1.2015.07.22.08.45.31 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 22 Jul 2015 08:45:31 -0700 (PDT) Received: by node.shutemov.name (Postfix, from userid 1000) id DCBDB40EE2; Wed, 22 Jul 2015 18:45:29 +0300 (EEST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=shutemov.name; s=default; t=1437579929; bh=nVHXx2A6wv91qBop3I2Jkkbxog+2TiZ8V9uPkJJZ2Ss=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=C64G6hbBs5TCJ1oESVgJFc75h/H9e6tggqJUXn9iP0juzWT54t2kBuqj4SRvSd/zP D2V0/om2RDpmq6j2bbT4Ic2Co9XR2wfnIU24biSm1yskbFMR/wrjquYEIQhqz02RcF 2TknQgOa5oH3SNwsRp8NgFxvDhxKm4w/K/D64TWA= Date: Wed, 22 Jul 2015 18:45:29 +0300 From: "Kirill A. Shutemov" To: Eric B Munson Cc: Andrew Morton , Michal Hocko , Vlastimil Babka , Paul Gortmaker , Chris Metcalf , Guenter Roeck , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH V4 5/6] mm: mmap: Add mmap flag to request VM_LOCKONFAULT Message-ID: <20150722154529.GA9107@node.dhcp.inet.fi> References: <1437508781-28655-1-git-send-email-emunson@akamai.com> <1437508781-28655-6-git-send-email-emunson@akamai.com> <20150722112558.GC8630@node.dhcp.inet.fi> <20150722143220.GB3203@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150722143220.GB3203@akamai.com> User-Agent: Mutt/1.5.23.1 (2014-03-12) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 48384 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: kirill@shutemov.name Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Wed, Jul 22, 2015 at 10:32:20AM -0400, Eric B Munson wrote: > On Wed, 22 Jul 2015, Kirill A. Shutemov wrote: > > > On Tue, Jul 21, 2015 at 03:59:40PM -0400, Eric B Munson wrote: > > > The cost of faulting in all memory to be locked can be very high when > > > working with large mappings. If only portions of the mapping will be > > > used this can incur a high penalty for locking. > > > > > > Now that we have the new VMA flag for the locked but not present state, > > > expose it as an mmap option like MAP_LOCKED -> VM_LOCKED. > > > > What is advantage over mmap() + mlock(MLOCK_ONFAULT)? > > There isn't one, it was added to maintain parity with the > mlock(MLOCK_LOCK) -> mmap(MAP_LOCKED) set. I think not having will lead > to confusion because we have MAP_LOCKED so why don't we support > LOCKONFAULT from mmap as well. I don't think it's ia good idea to spend bits in flags unless we have a reason for that. BTW, you have typo on sparc: s/0x8000/0x80000/. -- Kirill A. Shutemov