user/sven/linux.git/include/linux/sbitmap.h, branch v5.5.8

sbitmap: Delete sbitmap_any_bit_clear()

2019-11-13T19:50:40Z

Since the only caller of this function has been deleted, delete this one also. Signed-off-by: John Garry Signed-off-by: Jens Axboe

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 328

2019-06-05T15:37:06Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license v2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not see https www gnu org licenses extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Alexios Zavras Reviewed-by: Armijn Hemel Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000435.923873561@linutronix.de Signed-off-by: Greg Kroah-Hartman

sbitmap: trivial - update comment for sbitmap_deferred_clear_bit

2019-03-22T17:01:02Z

"sbitmap_batch_clear" should be "sbitmap_deferred_clear" Acked-by: Omar Sandoval Signed-off-by: Shenghui Wang Signed-off-by: Jens Axboe

sbitmap: add helpers for add/del wait queue handling

2018-12-20T19:17:05Z

After commit 5d2ee7122c73, users of sbitmap that need wait queue handling must use the provided helpers. But we only added prepare_to_wait()/finish_wait() style helpers, add the equivalent add_wait_queue/list_del wrappers as we.. This is needed to ensure kyber plays by the sbitmap waitqueue rules. Tested-by: Ming Lei Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe

sbitmap: fix sbitmap_for_each_set()

2018-12-04T00:03:58Z

We need to ignore bits in the cleared mask when iterating over all set bits. Fixes: ea86ea2cdced ("sbitmap: ammortize cost of clearing bits") Reported-by: Jens Axboe@kernel.dk> Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe

sbitmap: optimize wakeup check

2018-11-30T21:48:04Z

Even if we have no waiters on any of the sbitmap_queue wait states, we still have to loop every entry to check. We do this for every IO, so the cost adds up. Shift a bit of the cost to the slow path, when we actually have waiters. Wrap prepare_to_wait_exclusive() and finish_wait(), so we can maintain an internal count of how many are currently active. Then we can simply check this count in sbq_wake_ptr() and not have to loop if we don't have any sleepers. Convert the two users of sbitmap with waiting, blk-mq-tag and iSCSI. Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe

sbitmap: ammortize cost of clearing bits

2018-11-30T21:47:45Z

sbitmap maintains a set of words that we use to set and clear bits, with each bit representing a tag for blk-mq. Even though we spread the bits out and maintain a hint cache, one particular bit allocated will end up being cleared in the exact same spot. This introduces batched clearing of bits. Instead of clearing a given bit, the same bit is set in a cleared/free mask instead. If we fail allocating a bit from a given word, then we check the free mask, and batch move those cleared bits at that time. This trades 64 atomic bitops for 2 cmpxchg(). In a threaded poll test case, half the overhead of getting and clearing tags is removed with this change. On another poll test case with a single thread, performance is unchanged. Reviewed-by: Omar Sandoval Signed-off-by: Jens Axboe

scsi: target: sbitmap: add seq_file forward declaration

2018-07-11T02:42:47Z

The target core runs into a warning in the linux/sbitmap.h file in some configurations: In file included from include/target/target_core_base.h:7, from drivers/target/target_core_fabric_lib.c:41: include/linux/sbitmap.h:331:46: error: 'struct seq_file' declared inside parameter list will not be visible outside of this definition or declaration [-Werror] void sbitmap_show(struct sbitmap *sb, struct seq_file *m); ^~~~~~~~ In general, headers should not depend on others being included first, so this fixes it with a forward declaration for that struct name, but we probably want to merge the patch through the scsi tree to help bisection. Fixes: 10e9cbb6b531 ("scsi: target: Convert target drivers to use sbitmap") Signed-off-by: Arnd Bergmann Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval Reviewed-by: Jens Axboe Signed-off-by: Martin K. Petersen

blk-mq: avoid starving tag allocation after allocating process migrates

2018-05-24T17:00:39Z

When the allocation process is scheduled back and the mapped hw queue is changed, fake one extra wake up on previous queue for compensating wake up miss, so other allocations on the previous queue won't be starved. This patch fixes one request allocation hang issue, which can be triggered easily in case of very low nr_request. The race is as follows: 1) 2 hw queues, nr_requests are 2, and wake_batch is one 2) there are 3 waiters on hw queue 0 3) two in-flight requests in hw queue 0 are completed, and only two waiters of 3 are waken up because of wake_batch, but both the two waiters can be scheduled to another CPU and cause to switch to hw queue 1 4) then the 3rd waiter will wait for ever, since no in-flight request is in hw queue 0 any more. 5) this patch fixes it by the fake wakeup when waiter is scheduled to another hw queue Cc: Reviewed-by: Omar Sandoval Signed-off-by: Ming Lei Modified commit message to make it clearer, and make it apply on top of the 4.18 branch. Signed-off-by: Jens Axboe

sbitmap: fix missed wakeups caused by sbitmap_queue_get_shallow()

2018-05-10T17:27:36Z

The sbitmap queue wake batch is calculated such that once allocations start blocking, all of the bits which are already allocated must be enough to fulfill the batch counters of all of the waitqueues. However, the shallow allocation depth can break this invariant, since we block before our full depth is being utilized. Add sbitmap_queue_min_shallow_depth(), which saves the minimum shallow depth the sbq will use, and update sbq_calc_wake_batch() to take it into account. Acked-by: Paolo Valente Signed-off-by: Omar Sandoval Signed-off-by: Jens Axboe