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Date: Wed, 18 Jan 2012 10:20:03 +0900 From: Namhyung Kim <namhyung@...il.com> To: Tejun Heo <tj@...nel.org> CC: Namhyung Kim <namhyung.kim@....com>, Jens Axboe <axboe@...nel.dk>, linux-kernel@...r.kernel.org Subject: Re: [PATCH 2/3] block: prevent duplicated bio completion report Hi, 2012-01-18 2:45 AM, Tejun Heo wrote: > Hello, > > On Tue, Jan 17, 2012 at 10:32:07AM +0900, Namhyung Kim wrote: >> Since previous patch make block_bio_complete TP working, >> it will generate duplicated BLK_TA_COMPLETEs for bounced >> bios. Fix it. >> >> Signed-off-by: Namhyung Kim <namhyung.kim@....com> >> Cc: Tejun Heo <tj@...nel.org> > > This and the third patch should probably be merged to the first patch. > As it currently stands, it introduces window where spurious events are > generated. OK, will do. > >> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h >> index 4053cbd4490e..45cd0074a1c8 100644 >> --- a/include/linux/blk_types.h >> +++ b/include/linux/blk_types.h >> @@ -97,6 +97,9 @@ struct bio { >> #define BIO_MAPPED_INTEGRITY 11/* integrity metadata has been remapped */ >> #define bio_flagged(bio, flag) ((bio)->bi_flags& (1<< (flag))) >> >> +/* masked bio's won't report its completion via tracepoint */ >> +#define BIO_COMPLETE_MASK (1<< BIO_BOUNCED) > > And, who's setting this flag? __blk_queue_bounce() does. > >> /* >> * top 4 bits of bio flags indicate the pool this bio came from >> */ >> diff --git a/include/trace/events/block.h b/include/trace/events/block.h >> index 96955f4828b3..72888542e186 100644 >> --- a/include/trace/events/block.h >> +++ b/include/trace/events/block.h >> @@ -219,7 +219,8 @@ TRACE_EVENT_CONDITION(block_bio_complete, >> >> TP_ARGS(q, bio, error), >> >> - TP_CONDITION(bio->bi_bdev != NULL), >> + TP_CONDITION(bio->bi_bdev != NULL&& >> + !(bio->bi_flags& BIO_COMPLETE_MASK)), > > Bounced bio's are separate bio's too and I don't think masking its > completion from the TP itself is a good idea. As I wrote before, why > not do this from blktrace code? Because blktrace cannot know about the bi_flags, as I said before. :) And although the bounced bio's are separate ones, they aren't queued separately. They just get replaced on the way. Besides, I think accounting wait_time of them will result in an invalid value unless it's handled somehow in block_bio_bounce and/or block_rq_issue TP. Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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