From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH v2 4/6] block: switch to per-cpu in-flight counters Date: Wed, 5 Dec 2018 11:04:39 -0700 Message-ID: <779ca97e-3353-5fd0-9899-73de8a0b2cad@kernel.dk> References: <20181130222226.77216-1-snitzer@redhat.com> <20181130222226.77216-5-snitzer@redhat.com> <20181205174942.GA9838@redhat.com> <20181205180347.GA9966@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181205180347.GA9966@redhat.com> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Mike Snitzer Cc: linux-block@vger.kernel.org, dm-devel@redhat.com, Mikulas Patocka List-Id: dm-devel.ids On 12/5/18 11:03 AM, Mike Snitzer wrote: > On Wed, Dec 05 2018 at 12:54pm -0500, > Jens Axboe wrote: > >> On 12/5/18 10:49 AM, Mike Snitzer wrote: >>> On Wed, Dec 05 2018 at 12:30pm -0500, >>> Jens Axboe wrote: >>> >>>> There's also no need to pass in the cpu, if we're not running with >>>> preempt disabled already we have a problem. >>> >>> Why should this be any different than the part_stat_* interfaces? >>> __part_stat_add(), part_stat_read(), etc also use >>> per_cpu_ptr((part)->dkstats, (cpu) accessors. >> >> Maybe audit which ones actually need it? To answer the specific question, >> it's silly to pass in the cpu, if we're pinned already. That's true >> both programatically, but also for someone reading the code. > > I understand you'd like to avoid excess interface baggage. But seems to > me we'd be better off being consistent, when extending the percpu > portion of block core stats, and then do an incremental to clean it all > up. The incremental should be done first in that case, it'd be silly to introduce something only to do a cleanup right after. -- Jens Axboe