Currently flush_bg_queue() takes an input paramenter fiq, to which requests
in the bg_queue will be dispatched without respect to what's been set to
req->args->fiq. This behaviour totally breaks purpose of the request dispatching
algorithm when there are multiple input queues. So instead we need to enqueue
a request to its own req->args->fiq
Removes the unnecessary 'spin_lock(&fc->bg_lock)' operation before return
just to be unlocked later immediately. This can increase lock contention under
heavy workload, thus negatively affects performance.
Signed-off-by: Liu Kui <kui....@acronis.com>
Acked-by: Alexey Kuznetsov <kuz...@acronis.com>
---
fs/fuse/dev.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index fe26e8f..424180f 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -267,10 +267,12 @@ void fuse_queue_forget(struct fuse_conn *fc, struct
fuse_forget_link *forget,
}
}
-static void flush_bg_queue(struct fuse_conn *fc, struct fuse_iqueue *fiq)
+static void flush_bg_queue_and_unlock(struct fuse_conn *fc)
+__releases(fc->bg_lock)
{
struct fuse_req *req, *next;
LIST_HEAD(kio_reqs);
+ struct fuse_iqueue *fiq;
while (fc->active_background < fc->max_background &&
!list_empty(&fc->bg_queue)) {
@@ -287,17 +289,18 @@ static void flush_bg_queue(struct fuse_conn *fc, struct
fuse_iqueue *fiq)
} else if (ret < 0)
continue;
}
+ fiq = req->args->fiq;
spin_lock(&fiq->lock);
req->in.h.unique = fuse_get_unique(fiq);
queue_request_and_unlock(fiq, req);
}
spin_unlock(&fc->bg_lock);
+
list_for_each_entry_safe(req, next, &kio_reqs, list) {
list_del_init(&req->list);
fc->kio.op->req_send(req, true);
}
- spin_lock(&fc->bg_lock);
}
/*
@@ -356,8 +359,9 @@ void __fuse_request_end( struct fuse_req *req, bool
flush_bg)
fc->num_background--;
fc->active_background--;
if (flush_bg)
- flush_bg_queue(fc, fiq);
- spin_unlock(&fc->bg_lock);
+ flush_bg_queue_and_unlock(fc);
+ else
+ spin_unlock(&fc->bg_lock);
}
if (test_bit(FR_ASYNC, &req->flags)) {
@@ -609,6 +613,7 @@ static int fuse_request_queue_background(struct fuse_req
*req)
if (ff && test_bit(FUSE_S_FAIL_IMMEDIATELY, &ff->ff_state)) {
ret = -EIO;
} else if (likely(fc->connected)) {
+ ret = 0;
fc->num_background++;
if (fc->num_background == fc->max_background)
fc->blocked = 1;
@@ -622,17 +627,14 @@ static int fuse_request_queue_background(struct fuse_req
*req)
spin_lock(&fiq->lock);
req->in.h.unique = fuse_get_unique(fiq);
queue_request_and_unlock(fiq, req);
- ret = 0;
- goto unlock;
+ } else {
+ list_add_tail(&req->list, &fc->bg_queue);
+ flush_bg_queue_and_unlock(fc);
+ goto out;
}
-
- list_add_tail(&req->list, &fc->bg_queue);
- flush_bg_queue(fc, fiq);
- ret = 0;
}
-unlock:
spin_unlock(&fc->bg_lock);
-
+out:
return ret;
}
@@ -2297,11 +2299,7 @@ void fuse_abort_conn(struct fuse_conn *fc)
spin_lock(&fc->bg_lock);
fc->blocked = 0;
fc->max_background = UINT_MAX;
- for_each_online_cpu(cpu)
- flush_bg_queue(fc, per_cpu_ptr(fc->iqs, cpu));
- flush_bg_queue(fc, &fc->main_iq);
- spin_unlock(&fc->bg_lock);
-
+ flush_bg_queue_and_unlock(fc);
for_each_online_cpu(cpu)
fuse_abort_iqueue(per_cpu_ptr(fc->iqs, cpu), &to_end);
--
1.8.3.1
_______________________________________________
Devel mailing list
Devel@openvz.org
https://lists.openvz.org/mailman/listinfo/devel
