io_context sharing - anticipatory changes

changes to anticipatory io scheduler for io_context sharing

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 28 insertions, 6 deletions

diff --git a/block/as-iosched.c b/block/as-iosched.c
index cb5e53b05c7c..b201d16a7102 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -170,9 +170,11 @@ static void free_as_io_context(struct as_io_context *aic)
 
 static void as_trim(struct io_context *ioc)
 {
+        spin_lock(&ioc->lock);
         if (ioc->aic)
                 free_as_io_context(ioc->aic);
         ioc->aic = NULL;
+        spin_unlock(&ioc->lock);
 }
 
 /* Called when the task exits */
@@ -462,7 +464,9 @@ static void as_antic_timeout(unsigned long data)
         spin_lock_irqsave(q->queue_lock, flags);
         if (ad->antic_status == ANTIC_WAIT_REQ
                         || ad->antic_status == ANTIC_WAIT_NEXT) {
-                struct as_io_context *aic = ad->io_context->aic;
+                struct as_io_context *aic;
+                spin_lock(&ad->io_context->lock);
+                aic = ad->io_context->aic;
 
                 ad->antic_status = ANTIC_FINISHED;
                 kblockd_schedule_work(&ad->antic_work);
@@ -475,6 +479,7 @@ static void as_antic_timeout(unsigned long data)
                         /* process not "saved" by a cooperating request */
                         ad->exit_no_coop = (7*ad->exit_no_coop + 256)/8;
                 }
+                spin_unlock(&ad->io_context->lock);
         }
         spin_unlock_irqrestore(q->queue_lock, flags);
 }
@@ -635,9 +640,11 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
 
         ioc = ad->io_context;
         BUG_ON(!ioc);
+        spin_lock(&ioc->lock);
 
         if (rq && ioc == RQ_IOC(rq)) {
                 /* request from same process */
+                spin_unlock(&ioc->lock);
                 return 1;
         }
 
@@ -646,20 +653,25 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
                  * In this situation status should really be FINISHED,
                  * however the timer hasn't had the chance to run yet.
                  */
+                spin_unlock(&ioc->lock);
                 return 1;
         }
 
         aic = ioc->aic;
-        if (!aic)
+        if (!aic) {
+                spin_unlock(&ioc->lock);
                 return 0;
+        }
 
         if (atomic_read(&aic->nr_queued) > 0) {
                 /* process has more requests queued */
+                spin_unlock(&ioc->lock);
                 return 1;
         }
 
         if (atomic_read(&aic->nr_dispatched) > 0) {
                 /* process has more requests dispatched */
+                spin_unlock(&ioc->lock);
                 return 1;
         }
 
@@ -680,6 +692,7 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
                 }
 
                 as_update_iohist(ad, aic, rq);
+                spin_unlock(&ioc->lock);
                 return 1;
         }
 
@@ -688,20 +701,27 @@ static int as_can_break_anticipation(struct as_data *ad, struct request *rq)
                 if (aic->ttime_samples == 0)
                         ad->exit_prob = (7*ad->exit_prob + 256)/8;
 
-                if (ad->exit_no_coop > 128)
+                if (ad->exit_no_coop > 128) {
+                        spin_unlock(&ioc->lock);
                         return 1;
+                }
         }
 
         if (aic->ttime_samples == 0) {
-                if (ad->new_ttime_mean > ad->antic_expire)
+                if (ad->new_ttime_mean > ad->antic_expire) {
+                        spin_unlock(&ioc->lock);
                         return 1;
-                if (ad->exit_prob * ad->exit_no_coop > 128*256)
+                }
+                if (ad->exit_prob * ad->exit_no_coop > 128*256) {
+                        spin_unlock(&ioc->lock);
                         return 1;
+                }
         } else if (aic->ttime_mean > ad->antic_expire) {
                 /* the process thinks too much between requests */
+                spin_unlock(&ioc->lock);
                 return 1;
         }
-
+        spin_unlock(&ioc->lock);
         return 0;
 }
 
@@ -1255,7 +1275,9 @@ static void as_merged_requests(struct request_queue *q, struct request *req,
                          * Don't copy here but swap, because when anext is
                          * removed below, it must contain the unused context
                          */
+                        double_spin_lock(&rioc->lock, &nioc->lock, rioc < nioc);
                         swap_io_context(&rioc, &nioc);
+                        double_spin_unlock(&rioc->lock, &nioc->lock, rioc < nioc);
                 }
         }