From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id F2E691A0050 for ; Mon, 27 Jul 2015 17:15:24 +1000 (AEST) Received: by wicmv11 with SMTP id mv11so126633682wic.0 for ; Mon, 27 Jul 2015 00:15:21 -0700 (PDT) Date: Mon, 27 Jul 2015 10:15:18 +0300 From: "Kirill A. Shutemov" To: Eric B Munson Cc: Andrew Morton , Michal Hocko , Vlastimil Babka , Jonathan Corbet , 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-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH V5 4/7] mm: mlock: Add mlock flags to enable VM_LOCKONFAULT usage Message-ID: <20150727071518.GD11657@node.dhcp.inet.fi> References: <1437773325-8623-1-git-send-email-emunson@akamai.com> <1437773325-8623-5-git-send-email-emunson@akamai.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1437773325-8623-5-git-send-email-emunson@akamai.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Fri, Jul 24, 2015 at 05:28:42PM -0400, Eric B Munson wrote: > The previous patch introduced a flag that specified pages in a VMA > should be placed on the unevictable LRU, but they should not be made > present when the area is created. This patch adds the ability to set > this state via the new mlock system calls. > > We add MLOCK_ONFAULT for mlock2 and MCL_ONFAULT for mlockall. > MLOCK_ONFAULT will set the VM_LOCKONFAULT flag as well as the VM_LOCKED > flag for the target region. MCL_CURRENT and MCL_ONFAULT are used to > lock current mappings. With MCL_CURRENT all pages are made present and > with MCL_ONFAULT they are locked when faulted in. When specified with > MCL_FUTURE all new mappings will be marked with VM_LOCKONFAULT. > > Currently, mlockall() clears all VMA lock flags and then sets the > requested flags. For instance, if a process has MCL_FUTURE and > MCL_CURRENT set, but they want to clear MCL_FUTURE this would be > accomplished by calling mlockall(MCL_CURRENT). This still holds with > the introduction of MCL_ONFAULT. Each call to mlockall() resets all > VMA flags to the values specified in the current call. The new mlock2 > system call behaves in the same way. If a region is locked with > MLOCK_ONFAULT and a user wants to force it to be populated now, a second > call to mlock2(MLOCK_LOCKED) will accomplish this. > > munlock() will unconditionally clear both vma flags. munlockall() > unconditionally clears for VMA flags on all VMAs and in the > mm->def_flags field. > > Signed-off-by: Eric B Munson > Cc: Michal Hocko > Cc: Vlastimil Babka > Cc: Jonathan Corbet > Cc: "Kirill A. Shutemov" > Cc: linux-alpha@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mips@linux-mips.org > Cc: linux-parisc@vger.kernel.org > Cc: linuxppc-dev@lists.ozlabs.org > Cc: sparclinux@vger.kernel.org > Cc: linux-xtensa@linux-xtensa.org > Cc: linux-arch@vger.kernel.org > Cc: linux-api@vger.kernel.org > Cc: linux-mm@kvack.org > --- > Changes from V4: > * Split addition of VMA flag > > Changes from V3: > * Do extensive search for VM_LOCKED and ensure that VM_LOCKONFAULT is also handled > where appropriate > arch/alpha/include/uapi/asm/mman.h | 2 ++ > arch/mips/include/uapi/asm/mman.h | 2 ++ > arch/parisc/include/uapi/asm/mman.h | 2 ++ > arch/powerpc/include/uapi/asm/mman.h | 2 ++ > arch/sparc/include/uapi/asm/mman.h | 2 ++ > arch/tile/include/uapi/asm/mman.h | 3 +++ > arch/xtensa/include/uapi/asm/mman.h | 2 ++ Again, you can save few lines by moving some code into mman-common.h. Otherwise looks good. -- Kirill A. Shutemov