From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id 71DFA6B0071 for ; Thu, 2 Dec 2010 19:17:16 -0500 (EST) Received: from hpaq7.eem.corp.google.com (hpaq7.eem.corp.google.com [172.25.149.7]) by smtp-out.google.com with ESMTP id oB30HDXn018126 for ; Thu, 2 Dec 2010 16:17:14 -0800 Received: from pvg6 (pvg6.prod.google.com [10.241.210.134]) by hpaq7.eem.corp.google.com with ESMTP id oB30HBiQ003358 for ; Thu, 2 Dec 2010 16:17:12 -0800 Received: by pvg6 with SMTP id 6so1627184pvg.23 for ; Thu, 02 Dec 2010 16:17:11 -0800 (PST) From: Michel Lespinasse Subject: [PATCH 0/6] mlock: do not hold mmap_sem for extended periods of time Date: Thu, 2 Dec 2010 16:16:46 -0800 Message-Id: <1291335412-16231-1-git-send-email-walken@google.com> Sender: owner-linux-mm@kvack.org To: linux-mm@kvack.org, Andrew Morton , Hugh Dickins , Rik van Riel , Peter Zijlstra , Nick Piggin , KOSAKI Motohiro Cc: linux-kernel@vger.kernel.org, Linus Torvalds List-ID: Currently mlock() holds mmap_sem in exclusive mode while the pages get faulted in. In the case of a large mlock, this can potentially take a very long time, during which various commands such as 'ps auxw' will block. This makes sysadmins unhappy: real 14m36.232s user 0m0.003s sys 0m0.015s (output from 'time ps auxw' while a 20GB file was being mlocked without being previously preloaded into page cache) I propose that mlock() could release mmap_sem after the VM_LOCKED bits have been set in all appropriate VMAs. Then a second pass could be done to actually mlock the pages, in small batches, releasing mmap_sem when we block on disk access or when we detect some contention. Patches are against v2.6.37-rc4 plus my patches to avoid mlock dirtying (presently queued in -mm). Michel Lespinasse (6): mlock: only hold mmap_sem in shared mode when faulting in pages mm: add FOLL_MLOCK follow_page flag. mm: move VM_LOCKED check to __mlock_vma_pages_range() rwsem: implement rwsem_is_contended() mlock: do not hold mmap_sem for extended periods of time x86 rwsem: more precise rwsem_is_contended() implementation arch/alpha/include/asm/rwsem.h | 5 + arch/ia64/include/asm/rwsem.h | 5 + arch/powerpc/include/asm/rwsem.h | 5 + arch/s390/include/asm/rwsem.h | 5 + arch/sh/include/asm/rwsem.h | 5 + arch/sparc/include/asm/rwsem.h | 5 + arch/x86/include/asm/rwsem.h | 35 ++++++--- arch/x86/lib/rwsem_64.S | 4 +- arch/x86/lib/semaphore_32.S | 4 +- arch/xtensa/include/asm/rwsem.h | 5 + include/linux/mm.h | 1 + include/linux/rwsem-spinlock.h | 1 + lib/rwsem-spinlock.c | 12 +++ mm/internal.h | 3 +- mm/memory.c | 54 ++++++++++++-- mm/mlock.c | 150 ++++++++++++++++++-------------------- mm/nommu.c | 6 +- 17 files changed, 201 insertions(+), 104 deletions(-) -- 1.7.3.1 -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org