git: DragonFly_RELEASE_5_8 tmpfs - Change paging behavior, fix two directory-entry races
dillon at crater.dragonflybsd.org
Thu Apr 23 19:03:55 PDT 2020
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Wed Apr 22 19:24:13 2020 -0700
tmpfs - Change paging behavior, fix two directory-entry races
* Change the paging behavior for vfs.tmpfs.bufcache_mode.
These changes try to reduce unnecessary tmpfs flushes to swap when
the pageout daemon is able to locate sufficient clean VM pages.
The pageout daemon can still page tmpfs data to swap via its normal
operation, but tmpfs itself will not force write()s to pipeline to
swap unless memory pressure is severe.
0 tmpfs write()s are pipelined to swap via the buffer cache only
if the VM system is below the minimum free page count.
(this is the new default)
1 tmpfs write()s are pipelined to swap via the buffer cache when
the VM system is paging.
2 Same as (1) but be more aggressive about releasing buffer cache
3 tmpfs_write()s are always pipelined to swap via the buffer cache,
* Fix tmpfs file creation, hard-linking, and rename to ensure that the
new file is not created in a deleted directory. We must lock the
directory node around existing tests and add checks that were missing.
Also remove a few unnecessary recursive locks.
Summary of changes:
sys/vfs/tmpfs/tmpfs.h | 4 ++--
sys/vfs/tmpfs/tmpfs_subr.c | 33 +++++++++++++++++----------
sys/vfs/tmpfs/tmpfs_vfsops.c | 2 +-
sys/vfs/tmpfs/tmpfs_vnops.c | 54 ++++++++++++++++++++++++++++++--------------
4 files changed, 61 insertions(+), 32 deletions(-)
DragonFly BSD source repository
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