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  1. 08 11月, 2018 9 次提交
  3. 26 10月, 2018 1 次提交
  5. 16 10月, 2018 1 次提交
  7. 14 10月, 2018 4 次提交
  9. 09 10月, 2018 1 次提交
    • M
      blk-mq: complete req in softirq context in case of single queue · 36e76539
      由 Ming Lei 提交于 
      Lot of controllers may have only one irq vector for completing IO
request. And usually affinity of the only irq vector is all possible
CPUs, however, on most of ARCH, there may be only one specific CPU
for handling this interrupt.

So if all IOs are completed in hardirq context, it is inevitable to
degrade IO performance because of increased irq latency.

This patch tries to address this issue by allowing to complete request
in softirq context, like the legacy IO path.

IOPS is observed as ~13%+ in the following randread test on raid0 over
virtio-scsi.

mdadm --create --verbose /dev/md0 --level=0 --chunk=1024 --raid-devices=8 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi

fio --time_based --name=benchmark --runtime=30 --filename=/dev/md0 --nrfiles=1 --ioengine=libaio --iodepth=32 --direct=1 --invalidate=1 --verify=0 --verify_fatal=0 --numjobs=32 --rw=randread --blocksize=4k

Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: Zach Marano <zmarano@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      36e76539
  11. 28 9月, 2018 2 次提交
  13. 27 9月, 2018 2 次提交
  15. 21 8月, 2018 2 次提交
    • J
      blk-mq: sync the update nr_hw_queues with blk_mq_queue_tag_busy_iter · f5bbbbe4
      由 Jianchao Wang 提交于 
      For blk-mq, part_in_flight/rw will invoke blk_mq_in_flight/rw to
account the inflight requests. It will access the queue_hw_ctx and
nr_hw_queues w/o any protection. When updating nr_hw_queues and
blk_mq_in_flight/rw occur concurrently, panic comes up.

Before update nr_hw_queues, the q will be frozen. So we could use
q_usage_counter to avoid the race. percpu_ref_is_zero is used here
so that we will not miss any in-flight request. The access to
nr_hw_queues and queue_hw_ctx in blk_mq_queue_tag_busy_iter are
under rcu critical section, __blk_mq_update_nr_hw_queues could use
synchronize_rcu to ensure the zeroed q_usage_counter to be globally
visible.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      f5bbbbe4
    • J
      blk-mq: init hctx sched after update ctx and hctx mapping · d48ece20
      由 Jianchao Wang 提交于 
      Currently, when update nr_hw_queues, IO scheduler's init_hctx will
be invoked before the mapping between ctx and hctx is adapted
correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber)
may depend on this mapping and get wrong result and panic finally.
A simply way to fix this is that switch the IO scheduler to 'none'
before update the nr_hw_queues, and then switch it back after
update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due
to nobody use them any more.
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      d48ece20
  17. 09 8月, 2018 1 次提交
    • J
      blk-mq: count the hctx as active before allocating tag · d263ed99
      由 Jianchao Wang 提交于 
      Currently, we count the hctx as active after allocate driver tag
successfully. If a previously inactive hctx try to get tag first
time, it may fails and need to wait. However, due to the stale tag
->active_queues, the other shared-tags users are still able to
occupy all driver tags while there is someone waiting for tag.
Consequently, even if the previously inactive hctx is waked up, it
still may not be able to get a tag and could be starved.

To fix it, we count the hctx as active before try to allocate driver
tag, then when it is waiting the tag, the other shared-tag users
will reserve budget for it.
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJianchao Wang <jianchao.w.wang@oracle.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      d263ed99
  19. 25 7月, 2018 1 次提交
  21. 23 7月, 2018 1 次提交
    • M
      blk-mq: fail the request in case issue failure · 8824f622
      由 Ming Lei 提交于 
      Inside blk_mq_try_issue_list_directly(), if the request is issued as
failed, we shouldn't try to do it again, otherwise the warning in
blk_mq_start_request() will be triggered. This change is aligned to
behaviour of other ways of request issue & dispatch.

Fixes: 6ce3dd6e ("blk-mq: issue directly if hw queue isn't busy in case of 'none'")
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: LKP <lkp@01.org>
Reported-by: Nkernel test robot <rong.a.chen@intel.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      8824f622
  23. 18 7月, 2018 1 次提交
    • M
      blk-mq: issue directly if hw queue isn't busy in case of 'none' · 6ce3dd6e
      由 Ming Lei 提交于 
      In case of 'none' io scheduler, when hw queue isn't busy, it isn't
necessary to enqueue request to sw queue and dequeue it from
sw queue because request may be submitted to hw queue asap without
extra cost, meantime there shouldn't be much request in sw queue,
and we don't need to worry about effect on IO merge.

There are still some single hw queue SCSI HBAs(HPSA, megaraid_sas, ...)
which may connect high performance devices, so 'none' is often required
for obtaining good performance.

This patch improves IOPS and decreases CPU unilization on megaraid_sas,
per Kashyap's test.

Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Reported-by: NKashyap Desai <kashyap.desai@broadcom.com>
Tested-by: NKashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      6ce3dd6e
  25. 09 7月, 2018 10 次提交
  27. 29 6月, 2018 1 次提交
    • J
      blk-mq: don't queue more if we get a busy return · 1f57f8d4
      由 Jens Axboe 提交于 
      Some devices have different queue limits depending on the type of IO. A
classic case is SATA NCQ, where some commands can queue, but others
cannot. If we have NCQ commands inflight and encounter a non-queueable
command, the driver returns busy. Currently we attempt to dispatch more
from the scheduler, if we were able to queue some commands. But for the
case where we ended up stopping due to BUSY, we should not attempt to
retrieve more from the scheduler. If we do, we can get into a situation
where we attempt to queue a non-queueable command, get BUSY, then
successfully retrieve more commands from that scheduler and queue those.
This can repeat forever, starving the non-queuable command indefinitely.

Fix this by NOT attempting to pull more commands from the scheduler, if
we get a BUSY return. This should also be more optimal in terms of
letting requests stay in the scheduler for as long as possible, if we
get a BUSY due to the regular out-of-tags condition.
Reviewed-by: NOmar Sandoval <osandov@fb.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      1f57f8d4
  29. 24 6月, 2018 1 次提交
  31. 14 6月, 2018 1 次提交
  33. 13 6月, 2018 1 次提交
    • K
      treewide: kzalloc_node() -> kcalloc_node() · 590b5b7d
      由 Kees Cook 提交于 
      The kzalloc_node() function has a 2-factor argument form, kcalloc_node(). This
patch replaces cases of:

        kzalloc_node(a * b, gfp, node)

with:
        kcalloc_node(a * b, gfp, node)

as well as handling cases of:

        kzalloc_node(a * b * c, gfp, node)

with:

        kzalloc_node(array3_size(a, b, c), gfp, node)

as it's slightly less ugly than:

        kcalloc_node(array_size(a, b), c, gfp, node)

This does, however, attempt to ignore constant size factors like:

        kzalloc_node(4 * 1024, gfp, node)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
type TYPE;
expression THING, E;
@@

(
  kzalloc_node(
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  kzalloc_node(
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  kzalloc_node(
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  kzalloc_node(
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
identifier SIZE, COUNT;
@@

- kzalloc_node
+ kcalloc_node
  (
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  kzalloc_node(
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  kzalloc_node(
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc_node(
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc_node(
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  kzalloc_node(
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  kzalloc_node(
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  kzalloc_node(
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kzalloc_node(
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  kzalloc_node(
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
identifier STRIDE, SIZE, COUNT;
@@

(
  kzalloc_node(
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  kzalloc_node(
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  kzalloc_node(C1 * C2 * C3, ...)
|
  kzalloc_node(
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc_node(
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc_node(
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  kzalloc_node(
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  kzalloc_node(sizeof(THING) * C2, ...)
|
  kzalloc_node(sizeof(TYPE) * C2, ...)
|
  kzalloc_node(C1 * C2 * C3, ...)
|
  kzalloc_node(C1 * C2, ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	(E1) * E2
+	E1, E2
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- kzalloc_node
+ kcalloc_node
  (
-	E1 * E2
+	E1, E2
  , ...)
)
Signed-off-by: NKees Cook <keescook@chromium.org>
      590b5b7d