mirror_zfs/module
Brian Behlendorf 9c1a8eaa51 Fix ARC hit rate
When the compressed ARC feature was added in commit d3c2ae1
the method of reference counting in the ARC was modified.  As
part of this accounting change the arc_buf_add_ref() function
was removed entirely.

This would have be fine but the arc_buf_add_ref() function
served a second undocumented purpose of updating the ARC access
information when taking a hold on a dbuf.  Without this logic
in place a cached dbuf would not migrate its associated
arc_buf_hdr_t to the MFU list.  This would negatively impact
the ARC hit rate, particularly on systems with a small ARC.

This change reinstates the missing call to arc_access() from
dbuf_hold() by implementing a new arc_buf_access() function.

Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Tim Chase <tim@chase2k.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #6171
Closes #6852
Closes #6989
2018-01-30 10:27:31 -06:00
..
avl Fix uninitialized variable in avl_add() 2016-07-25 14:21:34 -07:00
icp Linux 4.14 compat: CONFIG_GCC_PLUGIN_RANDSTRUCT 2017-12-04 17:21:39 -08:00
nvpair Linux 4.14 compat: CONFIG_GCC_PLUGIN_RANDSTRUCT 2017-12-04 17:21:39 -08:00
unicode codebase style improvements for OpenZFS 6459 port 2017-01-22 13:25:40 -08:00
zcommon Fix buffer overflow in dsl_dataset_name() 2017-07-24 12:56:49 -07:00
zfs Fix ARC hit rate 2018-01-30 10:27:31 -06:00
zpios codebase style improvements for OpenZFS 6459 port 2017-01-22 13:25:40 -08:00
.gitignore Improve gitignore 2017-05-25 10:14:13 -07:00
Makefile.in GZIP compression offloading with QAT accelerator 2017-03-22 17:58:47 -07:00