diff options
Diffstat (limited to 'sys/dev/nvme/nvme_sysctl.c')
| -rw-r--r-- | sys/dev/nvme/nvme_sysctl.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/sys/dev/nvme/nvme_sysctl.c b/sys/dev/nvme/nvme_sysctl.c index 44b0ab7..08cd15e 100644 --- a/sys/dev/nvme/nvme_sysctl.c +++ b/sys/dev/nvme/nvme_sysctl.c @@ -33,6 +33,22 @@ __FBSDID("$FreeBSD$"); #include "nvme_private.h" +SYSCTL_NODE(_kern, OID_AUTO, nvme, CTLFLAG_RD, 0, "NVM Express"); +/* + * 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 by default. + * + * 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. + */ +int nvme_max_optimal_sectorsize = 1<<12; +SYSCTL_INT(_kern_nvme, OID_AUTO, max_optimal_sectorsize, CTLFLAG_RWTUN, + &nvme_max_optimal_sectorsize, 0, "The maximum optimal sectorsize reported"); + /* * CTLTYPE_S64 and sysctl_handle_64 were added in r217616. Define these * explicitly here for older kernels that don't include the r217616 |
