From: Lars Ellenberg <lars.ellenb...@linbit.com>
We try to limit the number of "in-flight" resync requests.
One condition for that is the amount of requested data should not exceed
half of what can be covered by our "max-buffers" setting.
However we compared number of 4k pages with number of in-flight 512 Byte
sectors, and this extra throttle triggered much earlier than intended.
Signed-off-by: Philipp Reisner <philipp.reis...@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenb...@linbit.com>
---
drivers/block/drbd/drbd_worker.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 0b5e429..9f0acb0 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -504,9 +504,9 @@ struct fifo_buffer *fifo_alloc(int fifo_size)
static int drbd_rs_controller(struct drbd_device *device, unsigned int sect_in)
{
struct disk_conf *dc;
- unsigned int want; /* The number of sectors we want in the proxy */
+ unsigned int want; /* The number of sectors we want in-flight */
int req_sect; /* Number of sectors to request in this turn */
- int correction; /* Number of sectors more we need in the proxy*/
+ int correction; /* Number of sectors more we need in-flight */
int cps; /* correction per invocation of drbd_rs_controller() */
int steps; /* Number of time steps to plan ahead */
int curr_corr;
@@ -577,8 +577,13 @@ static int drbd_rs_number_requests(struct drbd_device
*device)
* 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;
+
+ /* note that "number" is in units of "BM_BLOCK_SIZE" (which is 4k),
+ * mxb (as used here, and in drbd_alloc_pages on the peer) is
+ * "number of pages" (typically also 4k),
+ * but "rs_in_flight" is in "sectors" (512 Byte). */
+ if (mxb - device->rs_in_flight/8 < number)
+ number = mxb - device->rs_in_flight/8;
return number;
}
--
1.9.1
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