LU-7988 hsm: wake up cdt when requests are empty

The coordinator only runs once per second, we need a mechanism
to send more work when everything is done (cdt_request_count
goes to zero)

Without this, there is a hard limit of max_requests per sec
requests that can be processed, causing performance issues
with small files.

Lustre-change: https://review.whamcloud.com/29742
Lustre-commit: 7251fea8dc3c4d29e30c5a3f763c4c33d35f90a7

Signed-off-by: Ben Evans <bevans@cray.com>
Change-Id: I563666a1a3e53f0ec5908de593de71ff4d925467
Reviewed-by: Frank Zago <fzago@cray.com>
Reviewed-by: Sergey Cheremencev <cherementsev@gmail.com>
Signed-off-by: Minh Diep <minh.diep@intel.com>
Reviewed-on: https://review.whamcloud.com/30538
Tested-by: Jenkins
Reviewed-by: Sergey Cheremencev <c17829@cray.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>

diff --git a/lustre/mdt/mdt_coordinator.c b/lustre/mdt/mdt_coordinator.c
index 50f92bc..0251911 100644 (file)
--- a/lustre/mdt/mdt_coordinator.c
+++ b/lustre/mdt/mdt_coordinator.c
@@ -548,9 +548,11 @@ static int mdt_coordinator(void *data)
                 * repeatedly locking/unlocking the catalog for each request
                 * and preventing other HSM operations from happening */
                wait_event_interruptible_timeout(cdt->cdt_waitq,
-                                                kthread_should_stop(),
+                                                kthread_should_stop() ||
+                                                cdt->cdt_wakeup_coordinator,
                                                 wait_event_time);
 
+               cdt->cdt_wakeup_coordinator = false;
                CDEBUG(D_HSM, "coordinator resumes\n");
 
                if (kthread_should_stop()) {

diff --git a/lustre/mdt/mdt_hsm_cdt_requests.c b/lustre/mdt/mdt_hsm_cdt_requests.c
index 8b6dec7..688e827 100644 (file)
--- a/lustre/mdt/mdt_hsm_cdt_requests.c
+++ b/lustre/mdt/mdt_hsm_cdt_requests.c
@@ -432,7 +432,11 @@ int mdt_cdt_remove_request(struct coordinator *cdt, __u64 cookie)
        mdt_cdt_put_request(car);
 
        LASSERT(atomic_read(&cdt->cdt_request_count) >= 1);
-       atomic_dec(&cdt->cdt_request_count);
+       if (atomic_dec_and_test(&cdt->cdt_request_count)) {
+               /* request count is empty, nudge coordinator for more work */
+               cdt->cdt_wakeup_coordinator = true;
+               wake_up_interruptible(&cdt->cdt_waitq);
+       }
 
        RETURN(0);
 }

diff --git a/lustre/mdt/mdt_internal.h b/lustre/mdt/mdt_internal.h
index 90732cf..0ec751b 100644 (file)
--- a/lustre/mdt/mdt_internal.h
+++ b/lustre/mdt/mdt_internal.h
@@ -180,6 +180,8 @@ struct coordinator {
 
        /* Remove archive on last unlink policy */
        bool                     cdt_remove_archive_on_last_unlink;
+
+       bool                     cdt_wakeup_coordinator;
 };
 
 /* mdt state flag bits */