From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: [PATCH] md: make suspend range wait timed out Date: Sat, 17 Jun 2017 02:06:23 +0800 Message-ID: <40a41d94-b930-e402-9ce4-4d4f47873e64@fnarfbargle.com> References: <877f0c7gvr.fsf@notabene.neil.brown.name> <20170616155204.myffyxp5tuoctcoo@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170616155204.myffyxp5tuoctcoo@kernel.org> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li , NeilBrown Cc: linux-raid@vger.kernel.org, Shaohua Li , Mikulas Patocka List-Id: linux-raid.ids On 16/06/17 23:52, Shaohua Li wrote: > On Fri, Jun 16, 2017 at 01:26:00PM +1000, Neil Brown wrote: >> If an md device is left suspended, then the current code will block IO >> indefinitely. This patch will at a 20minute times to every single >> request, which will mean IO proceeds, but extremely slowly. I don't see >> that as a useful improvement. > > It returns error, so application will not dispatch more IO. But I agree a > timeout to clear the suspend looks a better policy. If you insist on doing this, make the default timeout configurable and set it to wait forever by default. That way there is no change in current behaviour. There are a number of times I've tickled those values to suspend things while doing something sinister to the array. I'd be mighty upset if I got called away and came back to find the kernel had resumed underneath me because it thinks it knows best. Regards, Brad -- Dolphins are so intelligent that within a few weeks they can train Americans to stand at the edge of the pool and throw them fish.