From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org
Cc: Ming Lei <ming.lei@redhat.com>, Omar Sandoval <osandov@fb.com>,
Kashyap Desai <kashyap.desai@broadcom.com>,
Sumanesh Samanta <sumanesh.samanta@broadcom.com>,
"Ewan D . Milne" <emilne@redhat.com>,
Hannes Reinecke <hare@suse.de>
Subject: [PATCH V6 03/13] sbitmap: add helpers for updating allocation hint
Date: Mon, 18 Jan 2021 08:49:11 +0800 [thread overview]
Message-ID: <20210118004921.202545-4-ming.lei@redhat.com> (raw)
In-Reply-To: <20210118004921.202545-1-ming.lei@redhat.com>
Add helpers for updating allocation hint, so that we can
avoid to duplicate code.
Prepare for moving allocation hint into sbitmap.
Cc: Omar Sandoval <osandov@fb.com>
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Tested-by: Sumanesh Samanta <sumanesh.samanta@broadcom.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
lib/sbitmap.c | 93 ++++++++++++++++++++++++++++++---------------------
1 file changed, 54 insertions(+), 39 deletions(-)
diff --git a/lib/sbitmap.c b/lib/sbitmap.c
index 7000636933b3..2b43a6aefec3 100644
--- a/lib/sbitmap.c
+++ b/lib/sbitmap.c
@@ -9,6 +9,55 @@
#include <linux/sbitmap.h>
#include <linux/seq_file.h>
+static int init_alloc_hint(struct sbitmap_queue *sbq, gfp_t flags)
+{
+ unsigned depth = sbq->sb.depth;
+
+ sbq->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
+ if (!sbq->alloc_hint)
+ return -ENOMEM;
+
+ if (depth && !sbq->sb.round_robin) {
+ int i;
+
+ for_each_possible_cpu(i)
+ *per_cpu_ptr(sbq->alloc_hint, i) = prandom_u32() % depth;
+ }
+
+ return 0;
+}
+
+static inline unsigned update_alloc_hint_before_get(struct sbitmap_queue *sbq,
+ unsigned int depth)
+{
+ unsigned hint;
+
+ hint = this_cpu_read(*sbq->alloc_hint);
+ if (unlikely(hint >= depth)) {
+ hint = depth ? prandom_u32() % depth : 0;
+ this_cpu_write(*sbq->alloc_hint, hint);
+ }
+
+ return hint;
+}
+
+static inline void update_alloc_hint_after_get(struct sbitmap_queue *sbq,
+ unsigned int depth,
+ unsigned int hint,
+ unsigned int nr)
+{
+ if (nr == -1) {
+ /* If the map is full, a hint won't do us much good. */
+ this_cpu_write(*sbq->alloc_hint, 0);
+ } else if (nr == hint || unlikely(sbq->sb.round_robin)) {
+ /* Only update the hint if we used it. */
+ hint = nr + 1;
+ if (hint >= depth - 1)
+ hint = 0;
+ this_cpu_write(*sbq->alloc_hint, hint);
+ }
+}
+
/*
* See if we have deferred clears that we can batch move
*/
@@ -355,17 +404,11 @@ int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
if (ret)
return ret;
- sbq->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
- if (!sbq->alloc_hint) {
+ if (init_alloc_hint(sbq, flags) != 0) {
sbitmap_free(&sbq->sb);
return -ENOMEM;
}
- if (depth && !round_robin) {
- for_each_possible_cpu(i)
- *per_cpu_ptr(sbq->alloc_hint, i) = prandom_u32() % depth;
- }
-
sbq->min_shallow_depth = UINT_MAX;
sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
atomic_set(&sbq->wake_index, 0);
@@ -418,24 +461,10 @@ int __sbitmap_queue_get(struct sbitmap_queue *sbq)
unsigned int hint, depth;
int nr;
- hint = this_cpu_read(*sbq->alloc_hint);
depth = READ_ONCE(sbq->sb.depth);
- if (unlikely(hint >= depth)) {
- hint = depth ? prandom_u32() % depth : 0;
- this_cpu_write(*sbq->alloc_hint, hint);
- }
+ hint = update_alloc_hint_before_get(sbq, depth);
nr = sbitmap_get(&sbq->sb, hint);
-
- if (nr == -1) {
- /* If the map is full, a hint won't do us much good. */
- this_cpu_write(*sbq->alloc_hint, 0);
- } else if (nr == hint || unlikely(sbq->sb.round_robin)) {
- /* Only update the hint if we used it. */
- hint = nr + 1;
- if (hint >= depth - 1)
- hint = 0;
- this_cpu_write(*sbq->alloc_hint, hint);
- }
+ update_alloc_hint_after_get(sbq, depth, hint, nr);
return nr;
}
@@ -449,24 +478,10 @@ int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
- hint = this_cpu_read(*sbq->alloc_hint);
depth = READ_ONCE(sbq->sb.depth);
- if (unlikely(hint >= depth)) {
- hint = depth ? prandom_u32() % depth : 0;
- this_cpu_write(*sbq->alloc_hint, hint);
- }
+ hint = update_alloc_hint_before_get(sbq, depth);
nr = sbitmap_get_shallow(&sbq->sb, hint, shallow_depth);
-
- if (nr == -1) {
- /* If the map is full, a hint won't do us much good. */
- this_cpu_write(*sbq->alloc_hint, 0);
- } else if (nr == hint || unlikely(sbq->sb.round_robin)) {
- /* Only update the hint if we used it. */
- hint = nr + 1;
- if (hint >= depth - 1)
- hint = 0;
- this_cpu_write(*sbq->alloc_hint, hint);
- }
+ update_alloc_hint_after_get(sbq, depth, hint, nr);
return nr;
}
--
2.28.0
next prev parent reply other threads:[~2021-01-18 0:53 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 0:49 [PATCH V6 00/13] blk-mq/scsi: tracking device queue depth via sbitmap Ming Lei
2021-01-18 0:49 ` [PATCH V6 01/13] sbitmap: remove sbitmap_clear_bit_unlock Ming Lei
2021-01-18 0:49 ` [PATCH V6 02/13] sbitmap: maintain allocation round_robin in sbitmap Ming Lei
2021-01-18 4:28 ` kernel test robot
2021-01-18 4:42 ` kernel test robot
2021-01-22 2:38 ` Ming Lei
2021-01-18 0:49 ` Ming Lei [this message]
2021-01-18 0:49 ` [PATCH V6 04/13] sbitmap: move allocation hint into sbitmap Ming Lei
2021-01-18 0:49 ` [PATCH V6 05/13] sbitmap: export sbitmap_weight Ming Lei
2021-01-18 0:49 ` [PATCH V6 06/13] sbitmap: add helper of sbitmap_calculate_shift Ming Lei
2021-01-18 0:49 ` [PATCH V6 07/13] blk-mq: add callbacks for storing & retrieving budget token Ming Lei
2021-01-18 0:49 ` [PATCH V6 08/13] blk-mq: return budget token from .get_budget callback Ming Lei
2021-01-18 0:49 ` [PATCH V6 09/13] scsi: put hot fields of scsi_host_template into one cacheline Ming Lei
2021-01-18 0:49 ` [PATCH V6 10/13] megaraid_sas: v2 replace sdev_busy with local counter Ming Lei
2021-01-18 0:49 ` [PATCH V6 11/13] scsi: add scsi_device_busy() to read sdev->device_busy Ming Lei
2021-01-18 0:49 ` [PATCH V6 12/13] scsi: make sure sdev->queue_depth is <= max(shost->can_queue, 1024) Ming Lei
2021-01-18 0:49 ` [PATCH V6 13/13] scsi: replace sdev->device_busy with sbitmap Ming Lei
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