D4446.1775693305.diff
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D4446.1775693305.diff
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	Index: sys/dev/nvd/nvd.c
	===================================================================
	--- sys/dev/nvd/nvd.c
	+++ sys/dev/nvd/nvd.c
	@@ -279,7 +279,18 @@
	disk->d_sectorsize = nvme_ns_get_sector_size(ns);
	disk->d_mediasize = (off_t)nvme_ns_get_size(ns);
	disk->d_delmaxsize = (off_t)nvme_ns_get_size(ns);
	- disk->d_stripesize = nvme_ns_get_stripesize(ns);
	+ /*
	+ * Intel NVMe controllers have a slow path for I/Os that span a 128KB
	+ * stripe boundary but ZFS limits ashift, which is derived from
	+ * d_stripesize, to 13 (8KB) so we limit the stripesize reported to
	+ * geom(8) to 4KB.
	+ *
	+ * This may result in a small number of additional I/Os to require
	+ * splitting in nvme(4), however the NVMe I/O path is very efficient
	+ * so these additional I/Os will cause very minimal (if any) difference
	+ * in performance or CPU utilisation.
	+ */
	+ disk->d_stripesize = MIN(nvme_ns_get_stripesize(ns), 1<<12);

	if (TAILQ_EMPTY(&disk_head))
	disk->d_unit = 0;