zfs/include
chrisrd 25d232f407 Scale the dbuf cache with arc_c
Commit d3c2ae1 introduced a dbuf cache with a default size of the
minimum of 100M or 1/32 maximum ARC size. (These figures may be adjusted
using dbuf_cache_max_bytes and dbuf_cache_max_shift.) The dbuf cache
is counted as metadata for the purposes of ARC size calculations.

On a 1GB box the ARC maximum size defaults to c_max 493M which gives a
dbuf cache default minimum size of 15.4M, and the ARC metadata defaults
to minimum 16M. I.e. the dbuf cache is an significant proportion of the
minimum metadata size. With other overheads involved this actually means
the ARC metadata doesn't get down to the minimum.

This patch dynamically scales the dbuf cache to the target ARC size
instead of statically scaling it to the maximum ARC size. (The scale is
still set by dbuf_cache_max_shift and the maximum size is still fixed by
dbuf_cache_max_bytes.) Using the target ARC size rather than the current
ARC size is done to help the ARC reach the target rather than simply
focusing on the current size.

Reviewed-by: Chunwei Chen <tuxoko@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Chris Dunlop <chris@onthe.net.au>
Issue #6506
Closes #6561
2017-10-16 10:57:54 -07:00
..
linux Linux 4.14 compat: IO acct, global_page_state, etc (#6655) 2017-09-19 14:24:34 -07:00
sys Scale the dbuf cache with arc_c 2017-10-16 10:57:54 -07:00
Makefile.am Kernel header installation should respect --prefix 2014-10-28 09:37:06 -07:00
libnvpair.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil.h Correct cppcheck errors (#6662) 2017-09-20 12:59:21 -07:00
libuutil_common.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libuutil_impl.h Support custom build directories and move includes 2010-09-08 12:38:56 -07:00
libzfs.h Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
libzfs_core.h OpenZFS 7600 - zfs rollback should pass target snapshot to kernel 2017-07-04 15:29:52 -07:00
libzfs_impl.h Multi-modifier protection (MMP) 2017-07-13 13:54:00 -04:00
zfeature_common.h OpenZFS 2932 - support crash dumps to raidz, etc. pools 2017-04-10 10:24:17 -07:00
zfs_comutil.h Illumos #2882, #2883, #2900 2013-09-04 15:49:00 -07:00
zfs_deleg.h Add support for user/group dnode accounting & quota 2016-10-07 09:45:13 -07:00
zfs_fletcher.h DLPX-44812 integrate EP-220 large memory scalability 2016-11-29 14:34:27 -08:00
zfs_namecheck.h OpenZFS 7386 - zfs get does not work properly with bookmarks 2017-01-26 14:42:15 -08:00
zfs_prop.h Check the dataset type more rigorously when fetching properties. 2014-05-06 10:41:46 -07:00
zpios-ctl.h Fix spelling 2017-01-03 11:31:18 -06:00
zpios-internal.h Fix spelling 2017-01-03 11:31:18 -06:00