From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 9F0B05F0001 for ; Wed, 8 Apr 2009 16:02:28 -0400 (EDT) Received: from zps35.corp.google.com (zps35.corp.google.com [172.25.146.35]) by smtp-out.google.com with ESMTP id n38K2PuT006315 for ; Wed, 8 Apr 2009 21:02:26 +0100 Received: from wf-out-1314.google.com (wfc28.prod.google.com [10.142.3.28]) by zps35.corp.google.com with ESMTP id n38K1mlZ020745 for ; Wed, 8 Apr 2009 13:02:24 -0700 Received: by wf-out-1314.google.com with SMTP id 28so241908wfc.26 for ; Wed, 08 Apr 2009 13:02:24 -0700 (PDT) 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org 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 List-ID: 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(-) -- 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