From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757712Ab2IDTn4 (ORCPT ); Tue, 4 Sep 2012 15:43:56 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:60485 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757657Ab2IDTny (ORCPT ); Tue, 4 Sep 2012 15:43:54 -0400 Date: Tue, 4 Sep 2012 12:43:50 -0700 From: Kent Overstreet To: Tejun Heo Cc: Mikulas Patocka , Vivek Goyal , linux-bcache@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com, bharrosh@panasas.com, Jens Axboe Subject: Re: [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers Message-ID: <20120904194350.GD25236@google.com> References: <20120829165006.GB20312@google.com> <20120829170711.GC12504@redhat.com> <20120829171345.GC20312@google.com> <20120830220745.GI27257@redhat.com> <20120831014359.GB15218@moria.home.lan> <20120904034100.GA21602@moria.home.lan> <20120904185540.GC3638@dhcp-172-17-108-109.mtv.corp.google.com> <20120904190119.GD3638@dhcp-172-17-108-109.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120904190119.GD3638@dhcp-172-17-108-109.mtv.corp.google.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 04, 2012 at 12:01:19PM -0700, Tejun Heo wrote: > On Tue, Sep 04, 2012 at 11:55:40AM -0700, Tejun Heo wrote: > > Actually, if the timer approach can reduce the frequency of rescuer > > involvement, I think it could actually be better. > > Ooh, it wouldn't. It's kicking in only after alloc failure. I don't > know. I think conditioning it on alloc failure is cleaner and > converting all per-bio allocations to front-pad makes sense. Using a > timer wouldn't make the mechanism any simpler, right? Exactly From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kent Overstreet Subject: Re: [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers Date: Tue, 4 Sep 2012 12:43:50 -0700 Message-ID: <20120904194350.GD25236@google.com> References: <20120829165006.GB20312@google.com> <20120829170711.GC12504@redhat.com> <20120829171345.GC20312@google.com> <20120830220745.GI27257@redhat.com> <20120831014359.GB15218@moria.home.lan> <20120904034100.GA21602@moria.home.lan> <20120904185540.GC3638@dhcp-172-17-108-109.mtv.corp.google.com> <20120904190119.GD3638@dhcp-172-17-108-109.mtv.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120904190119.GD3638-RcKxWJ4Cfj1J2suj2OqeGauc2jM2gXBXkQQo+JxHRPFibQn6LdNjmg@public.gmane.org> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tejun Heo Cc: Mikulas Patocka , Vivek Goyal , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org, Jens Axboe List-Id: linux-bcache@vger.kernel.org On Tue, Sep 04, 2012 at 12:01:19PM -0700, Tejun Heo wrote: > On Tue, Sep 04, 2012 at 11:55:40AM -0700, Tejun Heo wrote: > > Actually, if the timer approach can reduce the frequency of rescuer > > involvement, I think it could actually be better. > > Ooh, it wouldn't. It's kicking in only after alloc failure. I don't > know. I think conditioning it on alloc failure is cleaner and > converting all per-bio allocations to front-pad makes sense. Using a > timer wouldn't make the mechanism any simpler, right? Exactly