| Message ID | 20180925161213.15923-1-colyli@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | bcache: use REQ_PRIO to indicate bio for metadata | expand |
On 9/25/18 9:12 AM, Coly Li wrote: > In cached_dev_cache_miss() and check_should_bypass(), REQ_META is used > to check whether a bio is for metadata request. REQ_META is used for > blktrace, the correct REQ_ flag should be REQ_PRIO. This flag means the > bio should be prior to other bio, and frequently be used to indicate > metadata io in file system code. > > This patch replaces REQ_META with correct flag REQ_PRIO. > > CC Adam Manzanares because he explains to me what REQ_PRIO is for. Sorry for the confusion, I was talking about using the bi_ioprio field to pass ioprio information down to devices that support prioritized commands. I haven't used the REQ_PRIO flag in the work that I have done. > > Signed-off-by: Coly Li <colyli@suse.de> > Cc: Adam Manzanares <adam.manzanares@wdc.com> > --- > drivers/md/bcache/request.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c > index 51be355a3309..13d3355a90c0 100644 > --- a/drivers/md/bcache/request.c > +++ b/drivers/md/bcache/request.c > @@ -395,7 +395,7 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio) > * unless the read-ahead request is for metadata (eg, for gfs2). > */ > if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && > - !(bio->bi_opf & REQ_META)) > + !(bio->bi_opf & REQ_PRIO)) > goto skip; > > if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) || > @@ -877,7 +877,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, > } > > if (!(bio->bi_opf & REQ_RAHEAD) && > - !(bio->bi_opf & REQ_META) && > + !(bio->bi_opf & REQ_PRIO) && > s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) > reada = min_t(sector_t, dc->readahead >> 9, > get_capacity(bio->bi_disk) - bio_end_sector(bio)); >
On 9/26/18 12:32 AM, Adam Manzanares wrote: > > On 9/25/18 9:12 AM, Coly Li wrote: >> In cached_dev_cache_miss() and check_should_bypass(), REQ_META is used >> to check whether a bio is for metadata request. REQ_META is used for >> blktrace, the correct REQ_ flag should be REQ_PRIO. This flag means the >> bio should be prior to other bio, and frequently be used to indicate >> metadata io in file system code. >> >> This patch replaces REQ_META with correct flag REQ_PRIO. >> >> CC Adam Manzanares because he explains to me what REQ_PRIO is for. > Sorry for the confusion, I was talking about using the bi_ioprio field > to pass ioprio information down to devices that support prioritized > commands. I haven't used the REQ_PRIO flag in the work that I have done. Hi Adam, Aha, I misunderstood you. After 'git blame' I realize REQ_PRIO is invented by Christoph Hellwig, Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule, and lave REQ_META purely for marking requests as metadata in blktrace. From log of commit 65299a3b788b ("block: separate priority boosting from REQ_META") it seems this patch still uses REQ_PRIO in a correct way. And, thank you for clarifying this :-) Coly Li >> Signed-off-by: Coly Li <colyli@suse.de> >> Cc: Adam Manzanares <adam.manzanares@wdc.com> >> --- >> drivers/md/bcache/request.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c >> index 51be355a3309..13d3355a90c0 100644 >> --- a/drivers/md/bcache/request.c >> +++ b/drivers/md/bcache/request.c >> @@ -395,7 +395,7 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio) >> * unless the read-ahead request is for metadata (eg, for gfs2). >> */ >> if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && >> - !(bio->bi_opf & REQ_META)) >> + !(bio->bi_opf & REQ_PRIO)) >> goto skip; >> >> if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) || >> @@ -877,7 +877,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, >> } >> >> if (!(bio->bi_opf & REQ_RAHEAD) && >> - !(bio->bi_opf & REQ_META) && >> + !(bio->bi_opf & REQ_PRIO) && >> s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) >> reada = min_t(sector_t, dc->readahead >> 9, >> get_capacity(bio->bi_disk) - bio_end_sector(bio));
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c index 51be355a3309..13d3355a90c0 100644 --- a/drivers/md/bcache/request.c +++ b/drivers/md/bcache/request.c @@ -395,7 +395,7 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio) * unless the read-ahead request is for metadata (eg, for gfs2). */ if (bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND) && - !(bio->bi_opf & REQ_META)) + !(bio->bi_opf & REQ_PRIO)) goto skip; if (bio->bi_iter.bi_sector & (c->sb.block_size - 1) || @@ -877,7 +877,7 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s, } if (!(bio->bi_opf & REQ_RAHEAD) && - !(bio->bi_opf & REQ_META) && + !(bio->bi_opf & REQ_PRIO) && s->iop.c->gc_stats.in_use < CUTOFF_CACHE_READA) reada = min_t(sector_t, dc->readahead >> 9, get_capacity(bio->bi_disk) - bio_end_sector(bio));
In cached_dev_cache_miss() and check_should_bypass(), REQ_META is used to check whether a bio is for metadata request. REQ_META is used for blktrace, the correct REQ_ flag should be REQ_PRIO. This flag means the bio should be prior to other bio, and frequently be used to indicate metadata io in file system code. This patch replaces REQ_META with correct flag REQ_PRIO. CC Adam Manzanares because he explains to me what REQ_PRIO is for. Signed-off-by: Coly Li <colyli@suse.de> Cc: Adam Manzanares <adam.manzanares@wdc.com> --- drivers/md/bcache/request.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)