> Il giorno 05 mag 2018, alle ore 16:56, Mike Galbraith <efault@xxxxxx> 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 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), > > -Mike >