From 5dce03847fdc7bc6eb959282c0ae2117b1991746 Mon Sep 17 00:00:00 2001 From: Martin Matuska Date: Mon, 15 Feb 2021 09:10:01 +0100 Subject: [PATCH] zfs: Avoid updating the L2ARC device header unnecessarily From openzfs-master 0ae184a6b commit message: If we do not write any buffers to the cache device and the evict hand has not advanced do not update the cache device header. Cherry-picked from openzfs 0ae184a6baaf71e155e9b19af81b75474622ff58 Patch Author: George Amanakis MFC after: 3 days Reviewed by: delphij Differential Revision: https://reviews.freebsd.org/D28682 --- sys/contrib/openzfs/module/zfs/arc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/sys/contrib/openzfs/module/zfs/arc.c b/sys/contrib/openzfs/module/zfs/arc.c index e05b11d51942..fecc752e16ff 100644 --- a/sys/contrib/openzfs/module/zfs/arc.c +++ b/sys/contrib/openzfs/module/zfs/arc.c @@ -9062,6 +9062,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) l2arc_write_callback_t *cb = NULL; zio_t *pio, *wzio; uint64_t guid = spa_load_guid(spa); + l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; ASSERT3P(dev->l2ad_vdev, !=, NULL); @@ -9293,7 +9294,8 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) * Although we did not write any buffers l2ad_evict may * have advanced. */ - l2arc_dev_hdr_update(dev); + if (dev->l2ad_evict != l2dhdr->dh_evict) + l2arc_dev_hdr_update(dev); return (0); }