diff options
Diffstat (limited to 'man/man5/spl-module-parameters.5')
| -rw-r--r-- | man/man5/spl-module-parameters.5 | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/man/man5/spl-module-parameters.5 b/man/man5/spl-module-parameters.5 index 33e10b53c..2ec5b668e 100644 --- a/man/man5/spl-module-parameters.5 +++ b/man/man5/spl-module-parameters.5 @@ -83,6 +83,46 @@ Default value: \fB0\fR. .sp .ne 2 .na +\fBspl_kmem_alloc_warn\fR (uint) +.ad +.RS 12n +As a general rule kmem_alloc() allocations should be small, preferably +just a few pages since they must by physically contiguous. Therefore, a +rate limited warning will be printed to the console for any kmem_alloc() +which exceeds a reasonable threshold. + +The default warning threshold is set to eight pages but capped at 32K to +accommodate systems using large pages. This value was selected to be small +enough to ensure the largest allocations are quickly noticed and fixed. +But large enough to avoid logging any warnings when a allocation size is +larger than optimal but not a serious concern. Since this value is tunable, +developers are encouraged to set it lower when testing so any new largish +allocations are quickly caught. These warnings may be disabled by setting +the threshold to zero. +.sp +Default value: \fB32K\fR. +.RE + +.sp +.ne 2 +.na +\fBspl_kmem_alloc_max\fR (uint) +.ad +.RS 12n +Large kmem_alloc() allocations will fail if they exceed KMALLOC_MAX_SIZE. +Allocations which are marginally smaller than this limit may succeed but +should still be avoided due to the expense of locating a contiguous range +of free pages. Therefore, a maximum kmem size with reasonable safely +margin of 4x is set. Kmem_alloc() allocations larger than this maximum +will quickly fail. Vmem_alloc() allocations less than or equal to this +value will use kmalloc(), but shift to vmalloc() when exceeding this value. +.sp +Default value: \fBKMALLOC_MAX_SIZE/4\fR. +.RE + +.sp +.ne 2 +.na \fBspl_hostid\fR (ulong) .ad .RS 12n |