diff options
| -rw-r--r-- | drivers/block/drbd/drbd_receiver.c | 17 | ||||
| -rw-r--r-- | drivers/block/drbd/drbd_worker.c | 27 |
2 files changed, 29 insertions, 15 deletions
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 125c9e8..6ffbc22 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -234,9 +234,17 @@ static void drbd_kick_lo_and_reclaim_net(struct drbd_device *device) * @retry: whether to retry, if not enough pages are available right now * * Tries to allocate number pages, first from our own page pool, then from - * the kernel, unless this allocation would exceed the max_buffers setting. + * the kernel. * Possibly retry until DRBD frees sufficient pages somewhere else. * + * If this allocation would exceed the max_buffers setting, we throttle + * allocation (schedule_timeout) to give the system some room to breathe. + * + * We do not use max-buffers as hard limit, because it could lead to + * congestion and further to a distributed deadlock during online-verify or + * (checksum based) resync, if the max-buffers, socket buffer sizes and + * resync-rate settings are mis-configured. + * * Returns a page chain linked via page->private. */ struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int number, @@ -246,10 +254,8 @@ struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int struct page *page = NULL; struct net_conf *nc; DEFINE_WAIT(wait); - int mxb; + unsigned int mxb; - /* Yes, we may run up to @number over max_buffers. If we - * follow it strictly, the admin will get it wrong anyways. */ rcu_read_lock(); nc = rcu_dereference(peer_device->connection->net_conf); mxb = nc ? nc->max_buffers : 1000000; @@ -277,7 +283,8 @@ struct page *drbd_alloc_pages(struct drbd_peer_device *peer_device, unsigned int break; } - schedule(); + if (schedule_timeout(HZ/10) == 0) + mxb = UINT_MAX; } finish_wait(&drbd_pp_wait, &wait); diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index dcd95a6..7e633ca 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -492,10 +492,9 @@ struct fifo_buffer *fifo_alloc(int fifo_size) return fb; } -static int drbd_rs_controller(struct drbd_device *device) +static int drbd_rs_controller(struct drbd_device *device, unsigned int sect_in) { struct disk_conf *dc; - unsigned int sect_in; /* Number of sectors that came in since the last turn */ unsigned int want; /* The number of sectors we want in the proxy */ int req_sect; /* Number of sectors to request in this turn */ int correction; /* Number of sectors more we need in the proxy*/ @@ -505,9 +504,6 @@ static int drbd_rs_controller(struct drbd_device *device) int max_sect; struct fifo_buffer *plan; - sect_in = atomic_xchg(&device->rs_sect_in, 0); /* Number of sectors that came in */ - device->rs_in_flight -= sect_in; - dc = rcu_dereference(device->ldev->disk_conf); plan = rcu_dereference(device->rs_plan_s); @@ -550,11 +546,16 @@ static int drbd_rs_controller(struct drbd_device *device) static int drbd_rs_number_requests(struct drbd_device *device) { - int number; + unsigned int sect_in; /* Number of sectors that came in since the last turn */ + int number, mxb; + + sect_in = atomic_xchg(&device->rs_sect_in, 0); + device->rs_in_flight -= sect_in; rcu_read_lock(); + mxb = drbd_get_max_buffers(device) / 2; if (rcu_dereference(device->rs_plan_s)->size) { - number = drbd_rs_controller(device) >> (BM_BLOCK_SHIFT - 9); + number = drbd_rs_controller(device, sect_in) >> (BM_BLOCK_SHIFT - 9); device->c_sync_rate = number * HZ * (BM_BLOCK_SIZE / 1024) / SLEEP_TIME; } else { device->c_sync_rate = rcu_dereference(device->ldev->disk_conf)->resync_rate; @@ -562,8 +563,14 @@ static int drbd_rs_number_requests(struct drbd_device *device) } rcu_read_unlock(); - /* ignore the amount of pending requests, the resync controller should - * throttle down to incoming reply rate soon enough anyways. */ + /* Don't have more than "max-buffers"/2 in-flight. + * Otherwise we may cause the remote site to stall on drbd_alloc_pages(), + * potentially causing a distributed deadlock on congestion during + * online-verify or (checksum-based) resync, if max-buffers, + * socket buffer sizes and resync rate settings are mis-configured. */ + if (mxb - device->rs_in_flight < number) + number = mxb - device->rs_in_flight; + return number; } @@ -597,7 +604,7 @@ static int make_resync_request(struct drbd_device *device, int cancel) max_bio_size = queue_max_hw_sectors(device->rq_queue) << 9; number = drbd_rs_number_requests(device); - if (number == 0) + if (number <= 0) goto requeue; for (i = 0; i < number; i++) { |