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: Sun, 2 Sep 2012 18:17:52 -0700 Message-ID: <20120903011752.GC20060@moria.home.lan> References: <1346175456-1572-1-git-send-email-koverstreet@google.com> <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> <20120903004927.GM15292@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120903004927.GM15292@dastard> Sender: linux-bcache-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dave Chinner Cc: Vivek Goyal , Mikulas Patocka , 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 Mon, Sep 03, 2012 at 10:49:27AM +1000, Dave Chinner wrote: > Given that we are working around stack depth issues in the > filesystems already in several places, and now it seems like there's > a reason to work around it in the block layers as well, shouldn't we > simply increase the default stack size rather than introduce > complexity and performance regressions to try and work around not > having enough stack? > > I mean, we can deal with it like the ia32 4k stack issue was dealt > with (i.e. ignore those stupid XFS people, that's an XFS bug), or > we can face the reality that storage stacks have become so complex > that 8k is no longer a big enough stack for a modern system.... I'm not arguing against increasing the default stack size (I really don't have an opinion there) - but it's not a solution for the block layer, as stacking block devices can require an unbounded amount of stack without the generic_make_request() convert recursion-to-iteration thing.