kernel/git/stable/linux.git/block/blk-iolatency.c, branch master

blk-iolatency: clear delay state when freeing policy data

2026-08-15T23:15:08+00:00

io.latency can throttle a group which has no latency target of its own. When a sibling misses its target, check_scale_change() scales down its peers, and a peer that reaches queue depth one gets blkcg_use_delay() called on it on every further scale-down, even with min_lat_nsec == 0. iolatency_pd_offline() resets the target through iolatency_set_min_lat_nsec(), which clears the delay only on a nonzero to zero transition, so it never clears such a peer. Freeing the policy data then leaves blkg->use_delay set and blkcg->congestion_count elevated with nothing left that can drop it. blk_cgroup_congested() then returns true for every task in that cgroup and its descendants for as long as the cgroup lives: page_cache_sync_ra() cuts readahead to a single page, page_cache_async_ra() skips it altogether, and __folio_throttle_swaprate() takes swap_avail_lock and schedules a throttle on anonymous folio allocation. Clear the delay in iolatency_pd_free(). By then bio-held blkg references have drained, or the queue is frozen for policy deactivation, so check_scale_change() cannot re-arm it. The free callback can also see policy data which was never attached to a blkg, hence the pd->blkg check. Fixes: d70675121546 ("block: introduce blk-iolatency io controller") Signed-off-by: Usama Arif Acked-by: Tejun Heo Link: https://patch.msgid.link/20260814165712.510132-2-usama.arif@linux.dev Signed-off-by: Jens Axboe

block/blk-iolatency: account per-cpu latency stats over possible CPUs

2026-08-04T02:03:20+00:00

iolatency_check_latencies() and iolatency_ssd_stat() iterate a blkg's per-cpu latency stats with for_each_online_cpu(). When a CPU that has accumulated io.latency samples goes offline, its bucket is skipped: the check loop (which also resets) neither sums nor clears it, and the show path under-reports. On re-online the stranded samples are flushed into a later check window, which can trigger a spurious throttle/scale adjustment. Fixes: d70675121546 ("block: introduce blk-iolatency io controller") Fixes: 1fa2840e56f9 ("blk-iolatency: use a percentile approache for ssd's") Signed-off-by: Tao Cui Reviewed-by: Yu Kuai Link: https://patch.msgid.link/20260720093726.28965-3-cui.tao@linux.dev Signed-off-by: Jens Axboe

blk-cgroup: delay freeing policy data after rcu grace period

2026-06-24T12:37:54+00:00

Currently blkcg_print_blkgs() must hold RCU to iterate blkgs from a blkcg, and prfill() must hold queue_lock to prevent policy data from being freed by policy deactivation. As a consequence, queue_lock has to be nested under RCU from blkcg_print_blkgs(). Delay freeing policy data until after an RCU grace period so prfill() can be protected by RCU alone. Signed-off-by: Yu Kuai Link: https://patch.msgid.link/e20e5d984b41a026d61851966bed35eb094c4bff.1780621988.git.yukuai@fygo.io Signed-off-by: Jens Axboe

block/cgroup: Split blkg_conf_exit()

2026-06-05T19:41:11+00:00

Split blkg_conf_exit() into blkg_conf_unprep() and blkg_conf_close_bdev() because blkg_conf_exit() is not compatible with the Clang thread-safety annotations. Remove blkg_conf_exit(). Rename blkg_conf_exit_frozen() into blkg_conf_close_bdev_frozen(). Add thread-safety annotations to the new functions. Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Cc: Tejun Heo Signed-off-by: Bart Van Assche Reviewed-by: Chaitanya Kulkarni Link: https://patch.msgid.link/c1ec1f1c4b675bc5f187f77b3e6436234c6b244c.1780682325.git.bvanassche@acm.org Signed-off-by: Jens Axboe

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

block: introduce blk_queue_rot()

2026-01-29T20:15:50+00:00

To check if a request queue is for a rotational device, a double negation is needed with the pattern "!blk_queue_nonrot(q)". Simplify this with the introduction of the helper blk_queue_rot() which tests if a requests queue limit has the BLK_FEAT_ROTATIONAL feature set. All call sites of blk_queue_nonrot() are modified to use blk_queue_rot() and blk_queue_nonrot() definition removed. No functional changes. Signed-off-by: Damien Le Moal Reviewed-by: Nitesh Shetty Reviewed-by: Martin K. Petersen Signed-off-by: Jens Axboe

blk-mq: add QUEUE_FLAG_BIO_ISSUE_TIME

2025-09-10T11:23:45+00:00

bio->issue_time_ns is initialized for every bio, however, it's only used by blk-iolatency. Add a new queue_flag and only set this flag when blk-iolatency is enabled, so that extra blk_time_get_ns() can be saved for disks that blk-iolatency is not enabled. Signed-off-by: Yu Kuai Signed-off-by: Jens Axboe

block: cleanup bio_issue

2025-09-10T11:23:45+00:00

Now that bio->bi_issue is only used by blk-iolatency to get bio issue time, replace bio_issue with u64 time directly and remove bio_issue to make code cleaner. Signed-off-by: Yu Kuai Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe

treewide, timers: Rename from_timer() to timer_container_of()

2025-06-08T07:07:37+00:00

Move this API to the canonical timer_*() namespace. [ tglx: Redone against pre rc1 ] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com