Author: mav
Date: Mon Aug 5 11:48:40 2013
New Revision: 253958
URL: http://svnweb.freebsd.org/changeset/base/253958
Log:
MFprojects/camlock r249505:
Change CCB queue resize logic to be able safely handle overallocations:
- (re)allocate queue space in power of 2 chunks with 64 elements minimum
and never shrink it; with only 4/8 bytes per element size is insignificant.
- automatically reallocate the queue to double size if it is overflowed.
- if queue reallocation failed, store extra CCBs in unsorted TAILQ,
fetching them back as soon as some queue element is freed.
To free space in CCB for TAILQ linking, change highpowerq from keeping
high-power CCBs to keeping devices frozen due to high-power CCBs.
This encloses all pieces of queue resize logic inside of cam_queue.[ch],
removing some not obvious duties from xpt_release_ccb().
Modified:
head/sys/cam/cam.h
head/sys/cam/cam_queue.c
head/sys/cam/cam_queue.h
head/sys/cam/cam_xpt.c
head/sys/cam/cam_xpt_internal.h
Modified: head/sys/cam/cam.h
==============================================================================
--- head/sys/cam/cam.h Mon Aug 5 10:38:34 2013 (r253957)
+++ head/sys/cam/cam.h Mon Aug 5 11:48:40 2013 (r253958)
@@ -88,6 +88,7 @@ typedef struct {
#define CAM_UNQUEUED_INDEX -1
#define CAM_ACTIVE_INDEX -2
#define CAM_DONEQ_INDEX -3
+#define CAM_EXTRAQ_INDEX INT_MAX
} cam_pinfo;
/*
Modified: head/sys/cam/cam_queue.c
==============================================================================
--- head/sys/cam/cam_queue.c Mon Aug 5 10:38:34 2013 (r253957)
+++ head/sys/cam/cam_queue.c Mon Aug 5 11:48:40 2013 (r253958)
@@ -284,39 +284,24 @@ u_int32_t
cam_ccbq_resize(struct cam_ccbq *ccbq, int new_size)
{
int delta;
- int space_left;
delta = new_size - (ccbq->dev_active + ccbq->dev_openings);
- space_left = new_size
- - ccbq->queue.entries
- - ccbq->held
- - ccbq->dev_active;
-
- /*
- * Only attempt to change the underlying queue size if we are
- * shrinking it and there is space for all outstanding entries
- * in the new array or we have been requested to grow the array.
- * We don't fail in the case where we can't reduce the array size,
- * but clients that care that the queue be "garbage collected"
- * should detect this condition and call us again with the
- * same size once the outstanding entries have been processed.
- */
- if (space_left < 0
- || camq_resize(&ccbq->queue, new_size + (CAM_RL_VALUES - 1)) ==
- CAM_REQ_CMP) {
- ccbq->devq_openings += delta;
- ccbq->dev_openings += delta;
+ ccbq->devq_openings += delta;
+ ccbq->dev_openings += delta;
+
+ new_size = imax(64, 1 << fls(new_size + new_size / 2));
+ if (new_size > ccbq->queue.array_size)
+ return (camq_resize(&ccbq->queue, new_size));
+ else
return (CAM_REQ_CMP);
- } else {
- return (CAM_RESRC_UNAVAIL);
- }
}
int
cam_ccbq_init(struct cam_ccbq *ccbq, int openings)
{
bzero(ccbq, sizeof(*ccbq));
- if (camq_init(&ccbq->queue, openings + (CAM_RL_VALUES - 1)) != 0)
+ if (camq_init(&ccbq->queue,
+ imax(64, 1 << fls(openings + openings / 2))) != 0)
return (1);
ccbq->devq_openings = openings;
ccbq->dev_openings = openings;
Modified: head/sys/cam/cam_queue.h
==============================================================================
--- head/sys/cam/cam_queue.h Mon Aug 5 10:38:34 2013 (r253957)
+++ head/sys/cam/cam_queue.h Mon Aug 5 11:48:40 2013 (r253958)
@@ -57,6 +57,8 @@ SLIST_HEAD(ccb_hdr_slist, ccb_hdr);
struct cam_ccbq {
struct camq queue;
+ struct ccb_hdr_tailq queue_extra_head;
+ int queue_extra_entries;
int devq_openings;
int devq_allocating;
int dev_openings;
@@ -177,7 +179,7 @@ cam_ccbq_release_opening(struct cam_ccbq
static __inline int
cam_ccbq_pending_ccb_count(struct cam_ccbq *ccbq)
{
- return (ccbq->queue.entries);
+ return (ccbq->queue.entries + ccbq->queue_extra_entries);
}
static __inline void
@@ -190,14 +192,61 @@ cam_ccbq_take_opening(struct cam_ccbq *c
static __inline void
cam_ccbq_insert_ccb(struct cam_ccbq *ccbq, union ccb *new_ccb)
{
+ struct ccb_hdr *old_ccb;
+ struct camq *queue = &ccbq->queue;
+
ccbq->held--;
- camq_insert(&ccbq->queue, &new_ccb->ccb_h.pinfo);
+
+ /*
+ * If queue is already full, try to resize.
+ * If resize fail, push CCB with lowest priority out to the TAILQ.
+ */
+ if (queue->entries == queue->array_size &&
+ camq_resize(&ccbq->queue, queue->array_size * 2) != CAM_REQ_CMP) {
+ old_ccb = (struct ccb_hdr *)camq_remove(queue, queue->entries);
+ TAILQ_INSERT_HEAD(&ccbq->queue_extra_head, old_ccb,
+ xpt_links.tqe);
+ old_ccb->pinfo.index = CAM_EXTRAQ_INDEX;
+ ccbq->queue_extra_entries++;
+ }
+
+ camq_insert(queue, &new_ccb->ccb_h.pinfo);
}
static __inline void
cam_ccbq_remove_ccb(struct cam_ccbq *ccbq, union ccb *ccb)
{
- camq_remove(&ccbq->queue, ccb->ccb_h.pinfo.index);
+ struct ccb_hdr *cccb, *bccb;
+ struct camq *queue = &ccbq->queue;
+
+ /* If the CCB is on the TAILQ, remove it from there. */
+ if (ccb->ccb_h.pinfo.index == CAM_EXTRAQ_INDEX) {
+ TAILQ_REMOVE(&ccbq->queue_extra_head, &ccb->ccb_h,
+ xpt_links.tqe);
+ ccb->ccb_h.pinfo.index = CAM_UNQUEUED_INDEX;
+ ccbq->queue_extra_entries--;
+ return;
+ }
+
+ camq_remove(queue, ccb->ccb_h.pinfo.index);
+
+ /*
+ * If there are some CCBs on TAILQ, find the best one and move it
+ * to the emptied space in the queue.
+ */
+ bccb = TAILQ_FIRST(&ccbq->queue_extra_head);
+ if (bccb == NULL)
+ return;
+ TAILQ_FOREACH(cccb, &ccbq->queue_extra_head, xpt_links.tqe) {
+ if (bccb->pinfo.priority > cccb->pinfo.priority ||
+ (bccb->pinfo.priority == cccb->pinfo.priority &&
+ GENERATIONCMP(bccb->pinfo.generation, >,
+ cccb->pinfo.generation)))
+ bccb = cccb;
+ }
+ TAILQ_REMOVE(&ccbq->queue_extra_head, bccb, xpt_links.tqe);
+ ccbq->queue_extra_entries--;
+ camq_insert(queue, &bccb->pinfo);
}
static __inline union ccb *
Modified: head/sys/cam/cam_xpt.c
==============================================================================
--- head/sys/cam/cam_xpt.c Mon Aug 5 10:38:34 2013 (r253957)
+++ head/sys/cam/cam_xpt.c Mon Aug 5 11:48:40 2013 (r253958)
@@ -99,7 +99,7 @@ struct xpt_softc {
u_int32_t xpt_generation;
/* number of high powered commands that can go through right now */
- STAILQ_HEAD(highpowerlist, ccb_hdr) highpowerq;
+ STAILQ_HEAD(highpowerlist, cam_ed) highpowerq;
int num_highpower;
/* queue for handling async rescan requests. */
@@ -2684,7 +2684,7 @@ xpt_action_default(union ccb *start_ccb)
cgds->dev_openings = dev->ccbq.dev_openings;
cgds->dev_active = dev->ccbq.dev_active;
cgds->devq_openings = dev->ccbq.devq_openings;
- cgds->devq_queued = dev->ccbq.queue.entries;
+ cgds->devq_queued =
cam_ccbq_pending_ccb_count(&dev->ccbq);
cgds->held = dev->ccbq.held;
cgds->last_reset = tar->last_reset;
cgds->maxtags = dev->maxtags;
@@ -3255,8 +3255,8 @@ xpt_run_devq(struct cam_devq *devq)
*/
xpt_freeze_devq(work_ccb->ccb_h.path, 1);
STAILQ_INSERT_TAIL(&xsoftc.highpowerq,
- &work_ccb->ccb_h,
- xpt_links.stqe);
+ work_ccb->ccb_h.path->device,
+ highpowerq_entry);
mtx_unlock(&xsoftc.xpt_lock);
continue;
@@ -3778,11 +3778,6 @@ xpt_release_ccb(union ccb *free_ccb)
mtx_assert(sim->mtx, MA_OWNED);
cam_ccbq_release_opening(&device->ccbq);
- if (device->flags & CAM_DEV_RESIZE_QUEUE_NEEDED) {
- device->flags &= ~CAM_DEV_RESIZE_QUEUE_NEEDED;
- cam_ccbq_resize(&device->ccbq,
- device->ccbq.dev_openings + device->ccbq.dev_active);
- }
if (sim->ccb_count > sim->max_ccbs) {
xpt_free_ccb(free_ccb);
sim->ccb_count--;
@@ -4581,9 +4576,6 @@ xpt_dev_ccbq_resize(struct cam_path *pat
diff = newopenings - (dev->ccbq.dev_active + dev->ccbq.dev_openings);
result = cam_ccbq_resize(&dev->ccbq, newopenings);
- if (result == CAM_REQ_CMP && (diff < 0)) {
- dev->flags |= CAM_DEV_RESIZE_QUEUE_NEEDED;
- }
if ((dev->flags & CAM_DEV_TAG_AFTER_COUNT) != 0
|| (dev->inq_flags & SID_CmdQue) != 0)
dev->tag_saved_openings = newopenings;
@@ -4965,12 +4957,12 @@ camisr_runqueue(void *V_queue)
if (ccb_h->flags & CAM_HIGH_POWER) {
struct highpowerlist *hphead;
- union ccb *send_ccb;
+ struct cam_ed *device;
mtx_lock(&xsoftc.xpt_lock);
hphead = &xsoftc.highpowerq;
- send_ccb = (union ccb *)STAILQ_FIRST(hphead);
+ device = STAILQ_FIRST(hphead);
/*
* Increment the count since this command is done.
@@ -4980,12 +4972,12 @@ camisr_runqueue(void *V_queue)
/*
* Any high powered commands queued up?
*/
- if (send_ccb != NULL) {
+ if (device != NULL) {
- STAILQ_REMOVE_HEAD(hphead, xpt_links.stqe);
+ STAILQ_REMOVE_HEAD(hphead, highpowerq_entry);
mtx_unlock(&xsoftc.xpt_lock);
- xpt_release_devq(send_ccb->ccb_h.path,
+ xpt_release_devq_device(device,
/*count*/1, /*runqueue*/TRUE);
} else
mtx_unlock(&xsoftc.xpt_lock);
Modified: head/sys/cam/cam_xpt_internal.h
==============================================================================
--- head/sys/cam/cam_xpt_internal.h Mon Aug 5 10:38:34 2013
(r253957)
+++ head/sys/cam/cam_xpt_internal.h Mon Aug 5 11:48:40 2013
(r253958)
@@ -114,7 +114,6 @@ struct cam_ed {
#define CAM_DEV_REL_TIMEOUT_PENDING 0x02
#define CAM_DEV_REL_ON_COMPLETE 0x04
#define CAM_DEV_REL_ON_QUEUE_EMPTY 0x08
-#define CAM_DEV_RESIZE_QUEUE_NEEDED 0x10
#define CAM_DEV_TAG_AFTER_COUNT 0x20
#define CAM_DEV_INQUIRY_DATA_VALID 0x40
#define CAM_DEV_IN_DV 0x80
@@ -125,6 +124,7 @@ struct cam_ed {
u_int32_t tag_saved_openings;
u_int32_t refcount;
struct callout callout;
+ STAILQ_ENTRY(cam_ed) highpowerq_entry;
};
/*
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