Since commit 5b18b5a737
block: delete part_round_stats and switch to less precise counting,
io_ticks don't advance if io stall, iostat will show 0% io util.
This patch add back the logical, advance io_ticks if inflight > 0.
show 100% ioutil if io stall. This patch also show 100% ioutil if
queue quiesced, eg: scsi device blocked.
Signed-off-by: samuelliao <samuelliao@tencent.com>
[ Upstream commit 3edf5346e4f2ce2fa0c94651a90a8dda169565ee ]
For multiple split bios, if one of the bio is fail, the whole
should return error to application. But we found there is a race
between bio_integrity_verify_fn and bio complete, which return
io success to application after one of the bio fail. The race as
following:
split bio(READ) kworker
nvme_complete_rq
blk_update_request //split error=0
bio_endio
bio_integrity_endio
queue_work(kintegrityd_wq, &bip->bip_work);
bio_integrity_verify_fn
bio_endio //split bio
__bio_chain_endio
if (!parent->bi_status)
<interrupt entry>
nvme_irq
blk_update_request //parent error=7
req_bio_endio
bio->bi_status = 7 //parent bio
<interrupt exit>
parent->bi_status = 0
parent->bi_end_io() // return bi_status=0
The bio has been split as two: split and parent. When split
bio completed, it depends on kworker to do endio, while
bio_integrity_verify_fn have been interrupted by parent bio
complete irq handler. Then, parent bio->bi_status which have
been set in irq handler will overwrite by kworker.
In fact, even without the above race, we also need to conside
the concurrency beteen mulitple split bio complete and update
the same parent bi_status. Normally, multiple split bios will
be issued to the same hctx and complete from the same irq
vector. But if we have updated queue map between multiple split
bios, these bios may complete on different hw queue and different
irq vector. Then the concurrency update parent bi_status may
cause the final status error.
Suggested-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210331115359.1125679-1-yuyufen@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 2b8bd423614c595540eaadcfbc702afe8e155e50 upstream.
Currently io_ticks is approximated by adding one at each start and end of
requests if jiffies counter has changed. This works perfectly for requests
shorter than a jiffy or if one of requests starts/ends at each jiffy.
If disk executes just one request at a time and they are longer than two
jiffies then only first and last jiffies will be accounted.
Fix is simple: at the end of request add up into io_ticks jiffies passed
since last update rather than just one jiffy.
Example: common HDD executes random read 4k requests around 12ms.
fio --name=test --filename=/dev/sdb --rw=randread --direct=1 --runtime=30 &
iostat -x 10 sdb
Note changes of iostat's "%util" 8,43% -> 99,99% before/after patch:
Before:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sdb 0,00 0,00 82,60 0,00 330,40 0,00 8,00 0,96 12,09 12,09 0,00 1,02 8,43
After:
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sdb 0,00 0,00 82,50 0,00 330,00 0,00 8,00 1,00 12,10 12,10 0,00 12,12 99,99
Now io_ticks does not loose time between start and end of requests, but
for queue-depth > 1 some I/O time between adjacent starts might be lost.
For load estimation "%util" is not as useful as average queue length,
but it clearly shows how often disk queue is completely empty.
Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting")
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
From: "Banerjee, Debabrata" <dbanerje@akamai.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2cd896a5e86fc326bda8614b96c0401dcc145868 ]
If we hit the UINT_MAX limit of bio->bi_iter.bi_size and so we are anyway
not merging this page in this bio, then it make sense to make same_page
also as false before returning.
Without this patch, we hit below WARNING in iomap.
This mostly happens with very large memory system and / or after tweaking
vm dirty threshold params to delay writeback of dirty data.
WARNING: CPU: 18 PID: 5130 at fs/iomap/buffered-io.c:74 iomap_page_release+0x120/0x150
CPU: 18 PID: 5130 Comm: fio Kdump: loaded Tainted: G W 5.8.0-rc3 #6
Call Trace:
__remove_mapping+0x154/0x320 (unreliable)
iomap_releasepage+0x80/0x180
try_to_release_page+0x94/0xe0
invalidate_inode_page+0xc8/0x110
invalidate_mapping_pages+0x1dc/0x540
generic_fadvise+0x3c8/0x450
xfs_file_fadvise+0x2c/0xe0 [xfs]
vfs_fadvise+0x3c/0x60
ksys_fadvise64_64+0x68/0xe0
sys_fadvise64+0x28/0x40
system_call_exception+0xf8/0x1c0
system_call_common+0xf0/0x278
Fixes: cc90bc68422 ("block: fix "check bi_size overflow before merge"")
Reported-by: Shivaprasad G Bhat <sbhat@linux.ibm.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d81665198b83e55a28339d1f3e4890ed8a434556 ]
If we pass in an offset which is larger than PAGE_SIZE, then
page_is_mergeable() thinks it's not mergeable with the previous bio_vec,
leading to a large number of bio_vecs being used. Use a slightly more
obvious test that the two pages are compatible with each other.
Fixes: 52d52d1c98a9 ("block: only allow contiguous page structs in a bio_vec")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
samuelliao