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[146.241.23.50]) by smtp.gmail.com with ESMTPSA id p35-v6sm27401462wrb.12.2018.05.06.00.42.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 06 May 2018 00:42:53 -0700 (PDT) Mime-Version: 1.0 (Mac OS X Mail 11.3 \(3445.6.18\)) Subject: Re: [PATCH BUGFIX] block, bfq: postpone rq preparation to insert or merge From: Paolo Valente In-Reply-To: <1525532191.5406.15.camel@gmx.de> Date: Sun, 6 May 2018 09:42:51 +0200 Cc: Jens Axboe , linux-block , LKML , Ulf Hansson , Mark Brown , linus.walleij@linaro.org, bfq-iosched@googlegroups.com, oleksandr@natalenko.name Message-Id: <223CABEA-71E0-426F-A4AB-17BA8437C978@linaro.org> References: <20180504171701.6876-1-paolo.valente@linaro.org> <1525463210.622.1.camel@gmx.de> <1525508378.5406.6.camel@gmx.de> <9F155F9F-F6B2-465A-BA4D-A86FF6825071@linaro.org> <1525532191.5406.15.camel@gmx.de> To: Mike Galbraith X-Mailer: Apple Mail (2.3445.6.18) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP > Il giorno 05 mag 2018, alle ore 16:56, Mike Galbraith ha scritto: > > On Sat, 2018-05-05 at 12:39 +0200, Paolo Valente wrote: >> >> BTW, if you didn't run out of patience with this permanent issue yet, >> I was thinking of two o three changes to retry to trigger your failure >> reliably. > > Sure, fire away, I'll happily give the annoying little bugger > opportunities to show its tender belly. I've attached a compressed patch (to avoid possible corruption from my mailer). I'm little confident, but no pain, no gain, right? If possible, apply this patch on top of the fix I proposed in this thread, just to eliminate possible further noise. Finally, the patch content follows. Hoping for a stroke of luck, Paolo > > -Mike > diff --git a/block/bfq-mq-iosched.c b/block/bfq-mq-iosched.c index 118f319af7c0..6662efe29b69 100644 --- a/block/bfq-mq-iosched.c +++ b/block/bfq-mq-iosched.c @@ -525,8 +525,13 @@ static void bfq_limit_depth(unsigned int op, struct blk_mq_alloc_data *data) if (unlikely(bfqd->sb_shift != bt->sb.shift)) bfq_update_depths(bfqd, bt); +#if 0 data->shallow_depth = bfqd->word_depths[!!bfqd->wr_busy_queues][op_is_sync(op)]; +#else + data->shallow_depth = 1; +#endif + bfq_log(bfqd, "wr_busy %d sync %d depth %u", bfqd->wr_busy_queues, op_is_sync(op),