From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f175.google.com (mail-pd0-f175.google.com [209.85.192.175]) by kanga.kvack.org (Postfix) with ESMTP id B27F26B0031 for ; Mon, 2 Jun 2014 16:31:09 -0400 (EDT) Received: by mail-pd0-f175.google.com with SMTP id z10so3782726pdj.34 for ; Mon, 02 Jun 2014 13:31:09 -0700 (PDT) Received: from g2t2352.austin.hp.com (g2t2352.austin.hp.com. [15.217.128.51]) by mx.google.com with ESMTPS id qd5si17099702pbb.211.2014.06.02.13.31.08 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 02 Jun 2014 13:31:08 -0700 (PDT) Message-ID: <1401741061.5185.9.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH 0/5] mm: i_mmap_mutex to rwsem From: Davidlohr Bueso Date: Mon, 02 Jun 2014 13:31:01 -0700 In-Reply-To: <20140602130832.9328cfef977b7ed837d59321@linux-foundation.org> References: <1400816006-3083-1-git-send-email-davidlohr@hp.com> <1401416415.2618.14.camel@buesod1.americas.hpqcorp.net> <20140602130832.9328cfef977b7ed837d59321@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: mingo@kernel.org, peterz@infradead.org, riel@redhat.com, mgorman@suse.de, aswin@hp.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org On Mon, 2014-06-02 at 13:08 -0700, Andrew Morton wrote: > On Thu, 29 May 2014 19:20:15 -0700 Davidlohr Bueso wrote: > > > On Thu, 2014-05-22 at 20:33 -0700, Davidlohr Bueso wrote: > > > This patchset extends the work started by Ingo Molnar in late 2012, > > > optimizing the anon-vma mutex lock, converting it from a exclusive mutex > > > to a rwsem, and sharing the lock for read-only paths when walking the > > > the vma-interval tree. More specifically commits 5a505085 and 4fc3f1d6. > > > > > > The i_mmap_mutex has similar responsibilities with the anon-vma, protecting > > > file backed pages. Therefore we can use similar locking techniques: covert > > > the mutex to a rwsem and share the lock when possible. > > > > > > With the new optimistic spinning property we have in rwsems, we no longer > > > take a hit in performance when using this lock, and we can therefore > > > safely do the conversion. Tests show no throughput regressions in aim7 or > > > pgbench runs, and we can see gains from sharing the lock, in disk workloads > > > ~+15% for over 1000 users on a 8-socket Westmere system. > > > > > > This patchset applies on linux-next-20140522. > > > > ping? Andrew any chance of getting this in -next? > > (top-posting repaired) > > It was a bit late for 3.16 back on May 26, when you said "I will dig > deeper (probably for 3.17 now)". So, please take another look at the > patch factoring and let's get this underway for -rc1. Ok, so I meant that I'd dig deeper for the additional sharing opportunities (which I've found a few as Hugh correctly suggested). So those eventual patches could come later. But I see no reason for *this* patchset to be delayed, as even if it gets to be 3.17 material, I'd still very much want to have the same patch factoring I have now. I think its the correct way to handle lock transitioning for both correctness and bisectability. Thanks, Davidlohr -- 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