From 369706a6f887f8ffe1037d78bc31565ec701d72b Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Thu, 25 Feb 2021 10:04:44 -0500 Subject: [PATCH] buf: Fix the dirtybufthresh check dirtybufthresh is a watermark, slightly below the high watermark for dirty buffers. When a delayed write is issued, the dirtying thread will start flushing buffers if the dirtybufthresh watermark is reached. This helps ensure that the high watermark is not reached, otherwise performance will degrade as clustering and other optimizations are disabled (see buf_dirty_count_severe()). When the buffer cache was partitioned into "domains", the dirtybufthresh threshold checks were not updated. Fix this. Reported by: Shrikanth R Kamath Reviewed by: rlibby, mckusick, kib, bdrewery Sponsored by: Juniper Networks, Inc., Klara, Inc. Fixes: 3cec5c77d6 MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D28901 --- sys/kern/vfs_bio.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c index 45be14b47207..8e8cf3f083d4 100644 --- a/sys/kern/vfs_bio.c +++ b/sys/kern/vfs_bio.c @@ -2325,11 +2325,13 @@ void bufbdflush(struct bufobj *bo, struct buf *bp) { struct buf *nbp; + struct bufdomain *bd; - if (bo->bo_dirty.bv_cnt > dirtybufthresh + 10) { + bd = &bdomain[bo->bo_domain]; + if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh + 10) { (void) VOP_FSYNC(bp->b_vp, MNT_NOWAIT, curthread); altbufferflushes++; - } else if (bo->bo_dirty.bv_cnt > dirtybufthresh) { + } else if (bo->bo_dirty.bv_cnt > bd->bd_dirtybufthresh) { BO_LOCK(bo); /* * Try to find a buffer to flush.