Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932125AbaGAQSG (ORCPT ); Tue, 1 Jul 2014 12:18:06 -0400 Received: from zimbra13.linbit.com ([212.69.166.240]:53125 "EHLO zimbra13.linbit.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758126AbaGAQQ4 (ORCPT ); Tue, 1 Jul 2014 12:16:56 -0400 From: Philipp Reisner To: linux-kernel@vger.kernel.org, Jens Axboe Cc: drbd-dev@lists.linbit.com Subject: [PATCH 16/20] drbd: drbd_rs_number_requests: fix unit mismatch in comparison Date: Tue, 1 Jul 2014 18:16:46 +0200 Message-Id: <1404231410-29852-17-git-send-email-philipp.reisner@linbit.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1404231410-29852-1-git-send-email-philipp.reisner@linbit.com> References: <1404231410-29852-1-git-send-email-philipp.reisner@linbit.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lars Ellenberg 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 Signed-off-by: Lars Ellenberg --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/