From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <54F6F792.5060604@linux.vnet.ibm.com> Date: Wed, 04 Mar 2015 13:16:18 +0100 From: Christian Ehrhardt MIME-Version: 1.0 Subject: Re: [PATCH] fio: increase max smalloc pools References: <1425383094-9242-1-git-send-email-ehrhardt@de.ibm.com> <54F62FAC.8090208@kernel.dk> <54F63165.9040903@kernel.dk> In-Reply-To: <54F63165.9040903@kernel.dk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: Jens Axboe Cc: Christian Ehrhardt , fio@vger.kernel.org List-ID: On 03/03/15 23:10, Jens Axboe wrote: > On 03/03/2015 03:03 PM, Jens Axboe wrote: > > On 03/03/2015 04:44 AM, Christian Ehrhardt wrote: > >> From: Christian Ehrhardt > >> > >> For our tests with about 250k files we found the smalloc pool being > >> depleated. > >> Now for us values of 3-4 would be enough, but since it is a compile > >> time switch > >> I'd like to make it safe for everybody and set 8. > >> > >> Since it is a dynamic sizing anyway that should hopefully be ok for > >> everybody. > > > > The reason it was scaled down to 1 pool is because we could run into > > situations where one of the forked processes (or threads) would cause > > the expansion of pools, and smalloc() could then return memory that > > wasn't properly shared (or valid) between all jobs. This was recently > > found and fixed, and the smalloc code should probably just be updated to > > reflect that. We can't runtime add pools safely. > > > > Right now it's 1 pool at 16MB - how about we just bump it to 64MB for > > that one pool? Or, alternatively, pre-add 4 pools initially when smalloc > > is setup? > > Something like the attached, does that work for you? That's 4 pools of > 16MB added. I think that's more flexible than (the more ideal) 1 pool of > 64MB, since fio can survive if later pool additions fail. Or we can bump > it to 8x16 just to be on the safe side... > Hi, I saw you already checked it in with 8 max pools and your new code to initialize on sinit. We tested that and it works like a charm for our case now. Thank you.