Re: [PATCH v2] fuse: optimize over-io-uring request expiration check

[Joanne Koong <joannelkoong@gmail.com>]

On Sun, Feb 16, 2025 at 3:16 PM Bernd Schubert <bernd@bsbernd.com> wrote:
>
> On 2/3/25 20:37, Joanne Koong wrote:
> > On Mon, Feb 3, 2025 at 11:30 AM Joanne Koong <joannelkoong@gmail.com> wrote:
> >>
> >> Currently, when checking whether a request has timed out, we check
> >> fpq processing, but fuse-over-io-uring has one fpq per core and 256
> >> entries in the processing table. For systems where there are a
> >> large number of cores, this may be too much overhead.
> >>
> >> Instead of checking the fpq processing list, check ent_w_req_queue
> >> and ent_in_userspace.
> >>
> >> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> >> ---
> >>  fs/fuse/dev.c        |  2 +-
> >>  fs/fuse/dev_uring.c  | 26 +++++++++++++++++++++-----
> >>  fs/fuse/fuse_dev_i.h |  1 -
> >>  3 files changed, 22 insertions(+), 7 deletions(-)
> >>
> >
> > v1: https://lore.kernel.org/linux-fsdevel/20250123235251.1139078-1-joannelkoong@gmail.com/
> > Changes from v1 -> v2:
> > * Remove commit queue check, which should be fine since if the request
> > has expired while on this queue, it will be shortly processed anyways
> >
> >> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> >> index 3c03aac480a4..80a11ef4b69a 100644
> >> --- a/fs/fuse/dev.c
> >> +++ b/fs/fuse/dev.c
> >> @@ -45,7 +45,7 @@ bool fuse_request_expired(struct fuse_conn *fc, struct list_head *list)
> >>         return time_is_before_jiffies(req->create_time + fc->timeout.req_timeout);
> >>  }
> >>
> >> -bool fuse_fpq_processing_expired(struct fuse_conn *fc, struct list_head *processing)
> >> +static bool fuse_fpq_processing_expired(struct fuse_conn *fc, struct list_head *processing)
> >>  {
> >>         int i;
> >>
> >> diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
> >> index ab8c26042aa8..50f5b4e32ed5 100644
> >> --- a/fs/fuse/dev_uring.c
> >> +++ b/fs/fuse/dev_uring.c
> >> @@ -140,6 +140,21 @@ void fuse_uring_abort_end_requests(struct fuse_ring *ring)
> >>         }
> >>  }
> >>
> >> +static bool ent_list_request_expired(struct fuse_conn *fc, struct list_head *list)
> >> +{
> >> +       struct fuse_ring_ent *ent;
> >> +       struct fuse_req *req;
> >> +
> >> +       ent = list_first_entry_or_null(list, struct fuse_ring_ent, list);
> >> +       if (!ent)
> >> +               return false;
> >> +
> >> +       req = ent->fuse_req;
> >> +
> >> +       return time_is_before_jiffies(req->create_time +
> >> +                                     fc->timeout.req_timeout);
> >> +}
> >> +
> >>  bool fuse_uring_request_expired(struct fuse_conn *fc)
> >>  {
> >>         struct fuse_ring *ring = fc->ring;
> >> @@ -157,7 +172,8 @@ bool fuse_uring_request_expired(struct fuse_conn *fc)
> >>                 spin_lock(&queue->lock);
> >>                 if (fuse_request_expired(fc, &queue->fuse_req_queue) ||
> >>                     fuse_request_expired(fc, &queue->fuse_req_bg_queue) ||
> >> -                   fuse_fpq_processing_expired(fc, queue->fpq.processing)) {
> >> +                   ent_list_request_expired(fc, &queue->ent_w_req_queue) ||
> >> +                   ent_list_request_expired(fc, &queue->ent_in_userspace)) {
> >>                         spin_unlock(&queue->lock);
> >>                         return true;
> >>                 }
> >> @@ -495,7 +511,7 @@ static void fuse_uring_cancel(struct io_uring_cmd *cmd,
> >>         spin_lock(&queue->lock);
> >>         if (ent->state == FRRS_AVAILABLE) {
> >>                 ent->state = FRRS_USERSPACE;
> >> -               list_move(&ent->list, &queue->ent_in_userspace);
> >> +               list_move_tail(&ent->list, &queue->ent_in_userspace);
> >>                 need_cmd_done = true;
> >>                 ent->cmd = NULL;
> >>         }
> >> @@ -715,7 +731,7 @@ static int fuse_uring_send_next_to_ring(struct fuse_ring_ent *ent,
> >>         cmd = ent->cmd;
> >>         ent->cmd = NULL;
> >>         ent->state = FRRS_USERSPACE;
> >> -       list_move(&ent->list, &queue->ent_in_userspace);
> >> +       list_move_tail(&ent->list, &queue->ent_in_userspace);
> >>         spin_unlock(&queue->lock);
> >>
> >>         io_uring_cmd_done(cmd, 0, 0, issue_flags);
> >> @@ -769,7 +785,7 @@ static void fuse_uring_add_req_to_ring_ent(struct fuse_ring_ent *ent,
> >>         spin_unlock(&fiq->lock);
> >>         ent->fuse_req = req;
> >>         ent->state = FRRS_FUSE_REQ;
> >> -       list_move(&ent->list, &queue->ent_w_req_queue);
> >> +       list_move_tail(&ent->list, &queue->ent_w_req_queue);
> >>         fuse_uring_add_to_pq(ent, req);
> >>  }
> >>
> >> @@ -1185,7 +1201,7 @@ static void fuse_uring_send(struct fuse_ring_ent *ent, struct io_uring_cmd *cmd,
> >>
> >>         spin_lock(&queue->lock);
> >>         ent->state = FRRS_USERSPACE;
> >> -       list_move(&ent->list, &queue->ent_in_userspace);
> >> +       list_move_tail(&ent->list, &queue->ent_in_userspace);
> >>         ent->cmd = NULL;
> >>         spin_unlock(&queue->lock);
> >>
> >> diff --git a/fs/fuse/fuse_dev_i.h b/fs/fuse/fuse_dev_i.h
> >> index 3c4ae4d52b6f..19c29c6000a7 100644
> >> --- a/fs/fuse/fuse_dev_i.h
> >> +++ b/fs/fuse/fuse_dev_i.h
> >> @@ -63,7 +63,6 @@ void fuse_dev_queue_forget(struct fuse_iqueue *fiq,
> >>  void fuse_dev_queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req);
> >>
> >>  bool fuse_request_expired(struct fuse_conn *fc, struct list_head *list);
> >> -bool fuse_fpq_processing_expired(struct fuse_conn *fc, struct list_head *processing);
> >>
> >>  #endif
> >>
> >> --
> >> 2.43.5
> >>
> >
>
>
> Reviewed-by: Bernd Schubert <bernd@bsbernd.com>

Hi Miklos,

Is this patch acceptable to be merged into your tree?

Thanks,
Joanne