From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH v7 9/9] block: Avoid deadlocks with bio allocation by stacking drivers Date: Tue, 4 Sep 2012 15:39:49 -0400 Message-ID: <20120904193949.GC2603@redhat.com> References: <1346175456-1572-10-git-send-email-koverstreet@google.com> <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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Mikulas Patocka Cc: Kent Overstreet , linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, bharrosh-C4P08NqkoRlBDgjK7y7TUQ@public.gmane.org, Jens Axboe List-Id: linux-bcache@vger.kernel.org On Tue, Sep 04, 2012 at 03:26:19PM -0400, Mikulas Patocka wrote: [..] > BTW. can these new-style timerless plugs introduce deadlocks too? What > happens when some bios are indefinitely delayed because their requests are > held in a plug and a mempool runs out? I think they will not deadlock because these on stack bios/requests are flushed/dispatched when process schedules out. So if a submitter blocks on a mempool, it will be scheduled out and requests on plug will be dispatched. Thanks Vivek