diff options
Diffstat (limited to 'drivers/block/drbd/drbd_receiver.c')
| -rw-r--r-- | drivers/block/drbd/drbd_receiver.c | 17 |
1 files changed, 12 insertions, 5 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); |