From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765011AbZDHUCk (ORCPT ); Wed, 8 Apr 2009 16:02:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756920AbZDHUCb (ORCPT ); Wed, 8 Apr 2009 16:02:31 -0400 Received: from smtp-out.google.com ([216.239.45.13]:4901 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756114AbZDHUC3 (ORCPT ); Wed, 8 Apr 2009 16:02:29 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:date:message-id:subject:from:to:content-type: content-transfer-encoding:x-system-of-record; b=kmpr7f21VC/cUnra9ziB+TX1pErw63puskQPisA+4FyeeXojh9p+Ul2O1eqAJ4rRa BbTlodePUFI5/LREO+EFA== MIME-Version: 1.0 Date: Wed, 8 Apr 2009 13:02:23 -0700 Message-ID: <604427e00904081302p7aad170bu5ff0702415455f7@mail.gmail.com> Subject: [PATCH][0/2]page_fault retry with NOPAGE_RETRY From: Ying Han To: linux-mm@kvack.org, linux-kernel , akpm , torvalds@linux-foundation.org, Ingo Molnar , Mike Waychison , Rohit Seth , Hugh Dickins , Peter Zijlstra , "H. Peter Anvin" , =?ISO-8859-1?Q?T=F6r=F6k_Edwin?= , Lee Schermerhorn , Nick Piggin , Wu Fengguang Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org changelog[v3]: - applied fixes and cleanups from Wu Fengguang. filemap VM_FAULT_RETRY fixes [PATCH 01/14] mm: fix find_lock_page_retry() return value parsing [PATCH 02/14] mm: fix major/minor fault accounting on retried fault [PATCH 04/14] mm: reduce duplicate page fault code [PATCH 05/14] readahead: account mmap_miss for VM_FAULT_RETRY - split the patch into two parts. first part includes FAULT_FLAG_RETRY support with no current user change. second part includes individual per-architecture cleanups that enable FAULT_FLAG_RETRY. currently there are mainly two users for handle_mm_fault, we enable FAULT_FLAG_RETRY for actual fault handler and leave get_user_pages unchanged. Benchmarks: posted on [V1]: case 1. one application has a high count of threads each faulting in different pages of a hugefile. Benchmark indicate that this double data structure walking in case of major fault results in << 1% performance hit. case 2. add another thread in the above application which in a tight loop of mmap()/munmap(). Here we measure loop count in the new thread while other threads doing the same amount of work as case one. we got << 3% performance hit on the Complete Time(benchmark value for case one) and 10% performance improvement on the mmap()/munmap() counter. This patch helps a lot in cases we have writer which is waitting behind all readers, so it could execute much faster. some new test results from Wufengguang: Just tested the sparse-random-read-on-sparse-file case, and found the performance impact to be 0.4% (8.706s vs 8.744s). Kind of acceptable. without FAULT_FLAG_RETRY: iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.28s user 5.39s system 99% cpu 8.692 total iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.17s user 5.54s system 99% cpu 8.742 total iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.18s user 5.48s system 99% cpu 8.684 total FAULT_FLAG_RETRY: iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.18s user 5.63s system 99% cpu 8.825 total iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.22s user 5.47s system 99% cpu 8.718 total iotrace.rb --load stride-100 --mplay /mnt/btrfs-ram/sparse 3.13s user 5.55s system 99% cpu 8.690 total In the above faked workload, the mmap read page offsets are loaded from stride-100 and performed on /mnt/btrfs-ram/sparse, which are created by: seq 0 100 1000000 > stride-100 dd if=/dev/zero of=/mnt/btrfs-ram/sparse bs=1M count=1 seek=1024000 Signed-off-by: Ying Han Mike Waychison arch/x86/mm/fault.c | 20 ++++++++++++++ include/linux/fs.h | 2 +- include/linux/mm.h | 2 + mm/filemap.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++-- mm/memory.c | 33 +++++++++++++++++------ 5 files changed, 116 insertions(+), 13 deletions(-)