git: kernel - Refactor vnode_free_list, vnode reuse algorithm
dillon at crater.dragonflybsd.org
Mon Feb 22 07:56:30 PST 2010
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Mon Feb 22 07:40:05 2010 -0800
kernel - Refactor vnode_free_list, vnode reuse algorithm
* Rip out most of he VAGEx stuff. It might come back in another form
* Split the vnode_free_list into three parts, separated by two markers
(vnode_free_mid1 and vnode_free_mid2).
* Insert vnodes on the free list based on the following. New vnodes
are allocated from the base of the list.
At the HEAD - If the vnode is VRECLAIMED (i.e. dead)
end of first section - If the vnode has no cached VM or SWAP data
end of second section - If the vnode has cached SWAP data and no cached VM
at the TAIL - If the vnode has cached VM data
* Implement a rover to slowly scan vnodes in the list when allocating
and shift them to the appropriate section. This fixes a degenerate
condition in the placement of the markers.
* A Vnode is removed and usually immediately reinserted whenever it
is accesesd by userland but not held open, giving us a LRU-like
algorithm within each section of the list but non-LRU-like transits
between sections of the list.
Transits between sections are determined more by how the VM system
recycles related VM cache pages. Cached SWAP data only occurs if
the swapcache is turned on.
* Future: Might use VAGE to implement a second go-around in the queue
or a burst re-placement in the queue when the data set is found to
be too big to fit.
Summary of changes:
sys/kern/vfs_lock.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 90 insertions(+), 7 deletions(-)
DragonFly BSD source repository
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