* [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed
@ 2022-01-27 15:37 Ming Lei
2022-01-27 17:19 ` Bart Van Assche
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Ming Lei @ 2022-01-27 15:37 UTC (permalink / raw)
To: Martin K . Petersen, linux-scsi
Cc: Ming Lei, Bart Van Assche, Martin Wilck, Martin Wilck
Martin reported that sdev->queue_depth can often be changed in
->slave_configure(), and now we uses ->cmd_per_lun as initial queue
depth for setting up sdev->budget_map. And some extreme ->cmd_per_lun
or ->can_queue won't be used at default actually, if they are used to
allocate sdev->budget_map, huge memory may be consumed just because
of bad ->cmd_per_lun.
Fix the issue by reallocating sdev->budget_map after ->slave_configure()
returns, at that time, queue_depth should be much more reasonable.
Cc: Bart Van Assche <bvanassche@acm.org>
Reported-by: Martin Wilck <martin.wilck@suse.com>
Suggested-by: Martin Wilck <martin.wilck@suse.com>
Tested-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
V2:
- rename one local variable, and fix a comment grammar issue, as
reported by Bart
drivers/scsi/scsi_scan.c | 56 ++++++++++++++++++++++++++++++++++++----
1 file changed, 51 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 3520b9384428..4c7fb5a5ea4a 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -214,6 +214,48 @@ static void scsi_unlock_floptical(struct scsi_device *sdev,
SCSI_TIMEOUT, 3, NULL);
}
+static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
+ unsigned int depth)
+{
+ int new_shift = sbitmap_calculate_shift(depth);
+ bool need_alloc = !sdev->budget_map.map;
+ bool need_free = false;
+ int ret;
+ struct sbitmap sb_backup;
+
+ /*
+ * realloc if new shift is calculated, which is caused by setting
+ * up one new default queue depth after calling ->slave_configure
+ */
+ if (!need_alloc && new_shift != sdev->budget_map.shift)
+ need_alloc = need_free = true;
+
+ if (!need_alloc)
+ return 0;
+
+ /*
+ * Request queue has to be frozen for reallocating budget map,
+ * and here disk isn't added yet, so freezing is pretty fast
+ */
+ if (need_free) {
+ blk_mq_freeze_queue(sdev->request_queue);
+ sb_backup = sdev->budget_map;
+ }
+ ret = sbitmap_init_node(&sdev->budget_map,
+ scsi_device_max_queue_depth(sdev),
+ new_shift, GFP_KERNEL,
+ sdev->request_queue->node, false, true);
+ if (need_free) {
+ if (ret)
+ sdev->budget_map = sb_backup;
+ else
+ sbitmap_free(&sb_backup);
+ ret = 0;
+ blk_mq_unfreeze_queue(sdev->request_queue);
+ }
+ return ret;
+}
+
/**
* scsi_alloc_sdev - allocate and setup a scsi_Device
* @starget: which target to allocate a &scsi_device for
@@ -306,11 +348,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
* default device queue depth to figure out sbitmap shift
* since we use this queue depth most of times.
*/
- if (sbitmap_init_node(&sdev->budget_map,
- scsi_device_max_queue_depth(sdev),
- sbitmap_calculate_shift(depth),
- GFP_KERNEL, sdev->request_queue->node,
- false, true)) {
+ if (scsi_realloc_sdev_budget_map(sdev, depth)) {
put_device(&starget->dev);
kfree(sdev);
goto out;
@@ -1017,6 +1055,14 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
}
return SCSI_SCAN_NO_RESPONSE;
}
+
+ /*
+ * queue_depth is often changed in ->slave_configure, so
+ * setup budget map again for getting better memory uses
+ * since memory consumption of the map depends on queue
+ * depth heavily
+ */
+ scsi_realloc_sdev_budget_map(sdev, sdev->queue_depth);
}
if (sdev->scsi_level >= SCSI_3)
--
2.31.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed
2022-01-27 15:37 [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed Ming Lei
@ 2022-01-27 17:19 ` Bart Van Assche
2022-01-31 17:56 ` Martin K. Petersen
2022-02-01 2:03 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Bart Van Assche @ 2022-01-27 17:19 UTC (permalink / raw)
To: Ming Lei, Martin K . Petersen, linux-scsi; +Cc: Martin Wilck, Martin Wilck
On 1/27/22 07:37, Ming Lei wrote:
> Martin reported that sdev->queue_depth can often be changed in
> ->slave_configure(), and now we uses ->cmd_per_lun as initial queue
> depth for setting up sdev->budget_map. And some extreme ->cmd_per_lun
> or ->can_queue won't be used at default actually, if they are used to
> allocate sdev->budget_map, huge memory may be consumed just because
> of bad ->cmd_per_lun.
>
> Fix the issue by reallocating sdev->budget_map after ->slave_configure()
> returns, at that time, queue_depth should be much more reasonable.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed
2022-01-27 15:37 [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed Ming Lei
2022-01-27 17:19 ` Bart Van Assche
@ 2022-01-31 17:56 ` Martin K. Petersen
2022-02-01 2:03 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Martin K. Petersen @ 2022-01-31 17:56 UTC (permalink / raw)
To: Ming Lei
Cc: Martin K . Petersen, linux-scsi, Bart Van Assche, Martin Wilck,
Martin Wilck
Ming,
> Martin reported that sdev->queue_depth can often be changed in
> ->slave_configure(), and now we uses ->cmd_per_lun as initial queue
> depth for setting up sdev->budget_map. And some extreme ->cmd_per_lun
> or ->can_queue won't be used at default actually, if they are used to
> allocate sdev->budget_map, huge memory may be consumed just because of
> bad ->cmd_per_lun.
Applied to 5.17/scsi-fixes, thanks!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed
2022-01-27 15:37 [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed Ming Lei
2022-01-27 17:19 ` Bart Van Assche
2022-01-31 17:56 ` Martin K. Petersen
@ 2022-02-01 2:03 ` Martin K. Petersen
2 siblings, 0 replies; 4+ messages in thread
From: Martin K. Petersen @ 2022-02-01 2:03 UTC (permalink / raw)
To: Ming Lei, linux-scsi
Cc: Martin K . Petersen, Bart Van Assche, Martin Wilck, Martin Wilck
On Thu, 27 Jan 2022 23:37:33 +0800, Ming Lei wrote:
> Martin reported that sdev->queue_depth can often be changed in
> ->slave_configure(), and now we uses ->cmd_per_lun as initial queue
> depth for setting up sdev->budget_map. And some extreme ->cmd_per_lun
> or ->can_queue won't be used at default actually, if they are used to
> allocate sdev->budget_map, huge memory may be consumed just because
> of bad ->cmd_per_lun.
>
> [...]
Applied to 5.17/scsi-fixes, thanks!
[1/1] scsi: core: reallocate scsi device's budget map if default queue depth is changed
https://git.kernel.org/mkp/scsi/c/edb854a3680b
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-02-01 2:03 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-01-27 15:37 [PATCH V2] scsi: core: reallocate scsi device's budget map if default queue depth is changed Ming Lei
2022-01-27 17:19 ` Bart Van Assche
2022-01-31 17:56 ` Martin K. Petersen
2022-02-01 2:03 ` Martin K. Petersen
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