> On 3/16/21 12:44 AM, Changheun Lee wrote: > > Add limit_bio_size block sysfs node to limit bio size. > > Queue flag QUEUE_FLAG_LIMIT_BIO_SIZE will be set if limit_bio_size is set. > > And bio max size will be limited by queue max sectors via > > QUEUE_FLAG_LIMIT_BIO_SIZE set. > > > > Signed-off-by: Changheun Lee <nanich.lee@xxxxxxxxxxx> > > --- > > Documentation/ABI/testing/sysfs-block | 10 ++++++++++ > > Documentation/block/queue-sysfs.rst | 7 +++++++ > > block/blk-sysfs.c | 3 +++ > > 3 files changed, 20 insertions(+) > > > > diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block > > index e34cdeeeb9d4..86a7b15410cf 100644 > > --- a/Documentation/ABI/testing/sysfs-block > > +++ b/Documentation/ABI/testing/sysfs-block > > @@ -316,3 +316,13 @@ Description: > > does not complete in this time then the block driver timeout > > handler is invoked. That timeout handler can decide to retry > > the request, to fail it or to start a device recovery strategy. > > + > > +What: /sys/block/<disk>/queue/limit_bio_size > > +Date: Feb, 2021 > > +Contact: Changheun Lee <nanich.lee@xxxxxxxxxxx> > > +Description: > > + (RW) Toggle for set/clear QUEUE_FLAG_LIMIT_BIO_SIZE queue flag. > > + Queue flag QUEUE_FLAG_LIMIT_BIO_SIZE will be set if limit_bio_size > > + is set. And bio max size will be limited by queue max sectors. > > + QUEUE_FLAG_LIMIT_BIO_SIZE will be cleared if limit_bio_size is > > + cleard. And limit of bio max size will be cleard. > > diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst > > index 2638d3446b79..cd371a821855 100644 > > --- a/Documentation/block/queue-sysfs.rst > > +++ b/Documentation/block/queue-sysfs.rst > > @@ -273,4 +273,11 @@ devices are described in the ZBC (Zoned Block Commands) and ZAC > > do not support zone commands, they will be treated as regular block devices > > and zoned will report "none". > > > > +limit_bio_size (RW) > > +------------------- > > +This indicates QUEUE_FLAG_LIMIT_BIO_SIZE queue flag value. And > > +QUEUE_FLAG_LIMIT_BIO_SIZE can be changed via set(1)/clear(0) this node. > > +bio max size will be limited by queue max sectors via set this node. And > > +limit of bio max size will be cleard via clear this node. > > + > > Jens Axboe <jens.axboe@xxxxxxxxxx>, February 2009 > > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c > > index b513f1683af0..840d97f427e6 100644 > > --- a/block/blk-sysfs.c > > +++ b/block/blk-sysfs.c > > @@ -288,6 +288,7 @@ QUEUE_SYSFS_BIT_FNS(nonrot, NONROT, 1); > > QUEUE_SYSFS_BIT_FNS(random, ADD_RANDOM, 0); > > QUEUE_SYSFS_BIT_FNS(iostats, IO_STAT, 0); > > QUEUE_SYSFS_BIT_FNS(stable_writes, STABLE_WRITES, 0); > > +QUEUE_SYSFS_BIT_FNS(limit_bio_size, LIMIT_BIO_SIZE, 0); > > #undef QUEUE_SYSFS_BIT_FNS > > > > static ssize_t queue_zoned_show(struct request_queue *q, char *page) > > @@ -615,6 +616,7 @@ QUEUE_RW_ENTRY(queue_nonrot, "rotational"); > > QUEUE_RW_ENTRY(queue_iostats, "iostats"); > > QUEUE_RW_ENTRY(queue_random, "add_random"); > > QUEUE_RW_ENTRY(queue_stable_writes, "stable_writes"); > > +QUEUE_RW_ENTRY(queue_limit_bio_size, "limit_bio_size"); > > > > static struct attribute *queue_attrs[] = { > > &queue_requests_entry.attr, > > @@ -648,6 +650,7 @@ static struct attribute *queue_attrs[] = { > > &queue_rq_affinity_entry.attr, > > &queue_iostats_entry.attr, > > &queue_stable_writes_entry.attr, > > + &queue_limit_bio_size_entry.attr, > > &queue_random_entry.attr, > > &queue_poll_entry.attr, > > &queue_wc_entry.attr, > > Has it been considered to introduce a function to set the BIO size limit > instead of introducing a new sysfs attribute? See also > blk_queue_max_hw_sectors(). A function to set has been not considered yet. But sysfs attribute should be supported I think. Because it can be different depending on each system environment including policy. > > Thanks, > > Bart. Thanks, Changheun Lee