svn commit: r302649 - vendor-sys/illumos/dist/uts/common/fs/zfs
Andriy Gapon
avg at FreeBSD.org
Tue Jul 12 11:35:08 UTC 2016
Author: avg
Date: Tue Jul 12 11:35:07 2016
New Revision: 302649
URL: https://svnweb.freebsd.org/changeset/base/302649
Log:
7016 arc_available_memory is not 32-bit safe
illumos/illumos-gate at 0dd053d7d890618ea1fc697b07de364e69eb4190
https://github.com/illumos/illumos-gate/commit/0dd053d7d890618ea1fc697b07de364e69eb4190
https://www.illumos.org/issues/7016
upstream DLPX-39446 arc_available_memory is not 32-bit safe
https://github.com/delphix/delphix-os/commit/
6b353ea3b8a1610be22e71e657d051743c64190b
related to this upstream:
DLPX-38547 delphix engine hang
https://github.com/delphix/delphix-os/commit/
3183a567b3e8c62a74a65885ca60c86f3d693783
DLPX-38547 delphix engine hang (fix static global)
https://github.com/delphix/delphix-os/commit/
22ac551d8ef085ad66cc8f65e51ac372b12993b9
DLPX-38882 system hung waiting on free segment
https://github.com/delphix/delphix-os/commit/
cdd6beef7548cd3b12f0fc0328eeb3af540079c2
Reviewed by: Igor Kozhukhov <ikozhukhov at gmail.com>
Reviewed by: Matthew Ahrens <mahrens at delphix.com>
Reviewed by: Paul Dagnelie <pcd at delphix.com>
Reviewed by: George Wilson <george.wilson at delphix.com>
Approved by: Gordon Ross <gordon.ross at nexenta.com>
Author: Prakash Surya <prakash.surya at delphix.com>
Modified:
vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c
Modified: vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c
==============================================================================
--- vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c Tue Jul 12 11:34:05 2016 (r302648)
+++ vendor-sys/illumos/dist/uts/common/fs/zfs/arc.c Tue Jul 12 11:35:07 2016 (r302649)
@@ -216,6 +216,11 @@ static int arc_dead;
static boolean_t arc_warm;
/*
+ * log2 fraction of the zio arena to keep free.
+ */
+int arc_zio_arena_free_shift = 2;
+
+/*
* These tunables are for performance analysis.
*/
uint64_t zfs_arc_max;
@@ -3235,7 +3240,7 @@ arc_available_memory(void)
* heap is allocated. (Or, in the calculation, if less than 1/4th is
* free)
*/
- n = vmem_size(heap_arena, VMEM_FREE) -
+ n = (int64_t)vmem_size(heap_arena, VMEM_FREE) -
(vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC) >> 2);
if (n < lowest) {
lowest = n;
@@ -3246,15 +3251,16 @@ arc_available_memory(void)
/*
* If zio data pages are being allocated out of a separate heap segment,
* then enforce that the size of available vmem for this arena remains
- * above about 1/16th free.
+ * above about 1/4th (1/(2^arc_zio_arena_free_shift)) free.
*
- * Note: The 1/16th arena free requirement was put in place
- * to aggressively evict memory from the arc in order to avoid
- * memory fragmentation issues.
+ * Note that reducing the arc_zio_arena_free_shift keeps more virtual
+ * memory (in the zio_arena) free, which can avoid memory
+ * fragmentation issues.
*/
if (zio_arena != NULL) {
- n = vmem_size(zio_arena, VMEM_FREE) -
- (vmem_size(zio_arena, VMEM_ALLOC) >> 4);
+ n = (int64_t)vmem_size(zio_arena, VMEM_FREE) -
+ (vmem_size(zio_arena, VMEM_ALLOC) >>
+ arc_zio_arena_free_shift);
if (n < lowest) {
lowest = n;
r = FMR_ZIO_ARENA;
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