Ack
On Fri, Sep 29, 2023 at 5:17 PM Kui Liu <kui....@acronis.com> wrote:
>
> 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>
>
> ---
>
> 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 fe26e8f01609..424180ff7ab2 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);
>
> --
>
> 2.32.0 (Apple Git-132)
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