On 2017/10/28 上午10:39, tang.junhui@xxxxxxxxxx wrote:
> From: "tang.junhui" <tang.junhui@xxxxxxxxxx>
>
> Currently, Cache missed IOs are identified by s->cache_miss, but actually,
> there are many situations that missed IOs are not assigned a value for
> s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO
> (s->iop.bypass = 1), or the cache_bio allocate failed. In these situations,
> it will go to out_put or out_submit, and s->cache_miss is null, which leads
> bch_mark_cache_accounting() to treat this IO as a hit IO.
>
> Signed-off-by: tang.junhui <tang.junhui@xxxxxxxxxx>
It is good to me, thanks.
Reviewed-by: Coly Li <colyli@xxxxxxx>
Coly Li
> ---
> drivers/md/bcache/request.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
> index 76d2087..8f280e9 100644
> --- a/drivers/md/bcache/request.c
> +++ b/drivers/md/bcache/request.c
> @@ -468,6 +468,7 @@ struct search {
> unsigned recoverable:1;
> unsigned write:1;
> unsigned read_dirty_data:1;
> + unsigned cache_missed:1;
>
> unsigned long start_time;
>
> @@ -653,6 +654,7 @@ static inline struct search *search_alloc(struct bio *bio,
>
> s->orig_bio = bio;
> s->cache_miss = NULL;
> + s->cache_missed = 0;
> s->d = d;
> s->recoverable = 1;
> s->write = op_is_write(bio_op(bio));
> @@ -764,7 +766,7 @@ static void cached_dev_read_done_bh(struct closure *cl)
> struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
>
> bch_mark_cache_accounting(s->iop.c, s->d,
> - !s->cache_miss, s->iop.bypass);
> + !s->cache_missed, s->iop.bypass);
> trace_bcache_read(s->orig_bio, !s->cache_miss, s->iop.bypass);
>
> if (s->iop.error)
> @@ -783,6 +785,8 @@ static int cached_dev_cache_miss(struct btree *b, struct search *s,
> struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
> struct bio *miss, *cache_bio;
>
> + s->cache_missed = 1;
> +
> if (s->cache_miss || s->iop.bypass) {
> miss = bio_next_split(bio, sectors, GFP_NOIO, s->d->bio_split);
> ret = miss == bio ? MAP_DONE : MAP_CONTINUE;
>
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