From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Hildenbrand Subject: [PATCH v4 10/15] virtio-mem: Better retry handling Date: Thu, 7 May 2020 16:01:34 +0200 Message-ID: <20200507140139.17083-11-david@redhat.com> References: <20200507140139.17083-1-david@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200507140139.17083-1-david@redhat.com> Sender: kvm-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Pankaj Gupta , Jason Wang , Oscar Salvador , Igor Mammedov , Dave Young , Dan Williams , Pavel Tatashin , Stefan Hajnoczi , Vlastimil Babka List-Id: virtualization@lists.linuxfoundation.org Let's start with a retry interval of 5 seconds and double the time until we reach 5 minutes, in case we keep getting errors. Reset the retry interval in case we succeeded. The two main reasons for having to retry are - The hypervisor is busy and cannot process our request - We cannot reach the desired requested_size (esp., not enough memory can get unplugged because we can't allocate any subblocks). Tested-by: Pankaj Gupta Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Oscar Salvador Cc: Michal Hocko Cc: Igor Mammedov Cc: Dave Young Cc: Andrew Morton Cc: Dan Williams Cc: Pavel Tatashin Cc: Stefan Hajnoczi Cc: Vlastimil Babka Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index a2edb87e5ed8..eb4c16d634e0 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -141,7 +141,9 @@ struct virtio_mem { /* Timer for retrying to plug/unplug memory. */ struct hrtimer retry_timer; -#define VIRTIO_MEM_RETRY_TIMER_MS 30000 + unsigned int retry_timer_ms; +#define VIRTIO_MEM_RETRY_TIMER_MIN_MS 50000 +#define VIRTIO_MEM_RETRY_TIMER_MAX_MS 300000 /* Memory notifier (online/offline events). */ struct notifier_block memory_notifier; @@ -1550,6 +1552,7 @@ static void virtio_mem_run_wq(struct work_struct *work) switch (rc) { case 0: + vm->retry_timer_ms = VIRTIO_MEM_RETRY_TIMER_MIN_MS; break; case -ENOSPC: /* @@ -1565,8 +1568,7 @@ static void virtio_mem_run_wq(struct work_struct *work) */ case -ENOMEM: /* Out of memory, try again later. */ - hrtimer_start(&vm->retry_timer, - ms_to_ktime(VIRTIO_MEM_RETRY_TIMER_MS), + hrtimer_start(&vm->retry_timer, ms_to_ktime(vm->retry_timer_ms), HRTIMER_MODE_REL); break; case -EAGAIN: @@ -1586,6 +1588,8 @@ static enum hrtimer_restart virtio_mem_timer_expired(struct hrtimer *timer) retry_timer); virtio_mem_retry(vm); + vm->retry_timer_ms = min_t(unsigned int, vm->retry_timer_ms * 2, + VIRTIO_MEM_RETRY_TIMER_MAX_MS); return HRTIMER_NORESTART; } @@ -1754,6 +1758,7 @@ static int virtio_mem_probe(struct virtio_device *vdev) spin_lock_init(&vm->removal_lock); hrtimer_init(&vm->retry_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); vm->retry_timer.function = virtio_mem_timer_expired; + vm->retry_timer_ms = VIRTIO_MEM_RETRY_TIMER_MIN_MS; /* register the virtqueue */ rc = virtio_mem_init_vq(vm); -- 2.25.3