linux-stable.git/block/blk-stat.c, branch v6.2

block: make queue stat accounting a reference

2021-12-15T00:23:05+00:00

kyber turns on IO statistics when it is loaded on a queue, which means
that even if kyber is then later unloaded, we're still stuck with stats
enabled on the queue.

Change the account enabled from a bool to an int, and pair the enable call
with the equivalent disable call. This ensures that stats gets turned off
again appropriately.

Reviewed-by: Omar Sandoval 
Signed-off-by: Jens Axboe

block: only allocate poll_stats if there's a user of them

2021-11-29T13:38:35+00:00

This is essentially never used, yet it's about 1/3rd of the total
queue size. Allocate it when needed, and don't embed it in the queue.

Kill the queue flag for this while at it, since we can just check the
assigned pointer now.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-stat: make q->stats->lock irqsafe

2020-09-01T22:48:46+00:00

blk-iocost calls blk_stat_enable_accounting() while holding an irqsafe lock
which triggers a lockdep splat because q->stats->lock isn't irqsafe. Let's
make it irqsafe.

Signed-off-by: Tejun Heo 
Fixes: cd006509b0a9 ("blk-iocost: account for IO size when testing latencies")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Jens Axboe

blk-stat: Optimise blk_stat_add()

2019-10-08T03:19:10+00:00

blk_stat_add() calls {get,put}_cpu_ptr() in a loop, which entails
overhead of disabling/enabling preemption. The loop is under RCU
(i.e.short) anyway, so do get_cpu() in advance.

Signed-off-by: Pavel Begunkov 
Signed-off-by: Jens Axboe

block: add SPDX tags to block layer files missing licensing information

2019-04-30T22:12:03+00:00

Various block layer files do not have any licensing information at all.
Add SPDX tags for the default kernel GPLv2 license to those.

Reviewed-by: Chaitanya Kulkarni 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: remove a few unused exports

2018-11-15T19:13:25+00:00

Reviewed-by: Hannes Reinecke 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: export blk_stat_enable_accounting()

2018-09-27T23:34:54+00:00

Kyber will need this in a future change if it is built as a module.

Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe

blk-stat: export helpers for modifying blk_rq_stat

2018-07-09T15:07:54+00:00

We need to use blk_rq_stat in the blkcg qos stuff, so export some of
these helpers so they can be used by other things.

Signed-off-by: Josef Bacik 
Acked-by: Tejun Heo 
Signed-off-by: Jens Axboe

block: consolidate struct request timestamp fields

2018-05-09T14:33:09+00:00

Currently, struct request has four timestamp fields:

- A start time, set at get_request time, in jiffies, used for iostats
- An I/O start time, set at start_request time, in ktime nanoseconds,
  used for blk-stats (i.e., wbt, kyber, hybrid polling)
- Another start time and another I/O start time, used for cfq and bfq

These can all be consolidated into one start time and one I/O start
time, both in ktime nanoseconds, shaving off up to 16 bytes from struct
request depending on the kernel config.

Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe

block: get rid of struct blk_issue_stat

2018-05-09T14:33:05+00:00

struct blk_issue_stat squashes three things into one u64:

- The time the driver started working on a request
- The original size of the request (for the io.low controller)
- Flags for writeback throttling

It turns out that on x86_64, we have a 4 byte hole in struct request
which we can fill with the non-timestamp fields from blk_issue_stat,
simplifying things quite a bit.

Signed-off-by: Omar Sandoval 
Signed-off-by: Jens Axboe