mirror of
https://github.com/torvalds/linux.git
synced 2024-11-08 21:21:47 +00:00
fa0d7e3de6
RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk> |
||
|---|---|---|
| .. | ||
| bitmap.c | ||
| dir.c | ||
| inode.c | ||
| Kconfig | ||
| Makefile | ||
| namei.c | ||
| qnx4.h | ||
| README | ||
This is a snapshot of the QNX4 filesystem for Linux. Please send diffs and remarks to <al@alarsen.net> . Credits : Richard "Scuba" A. Frowijn <scuba@wxs.nl> Frank "Jedi/Sector One" Denis <j@pureftpd.org> Anders Larsen <al@alarsen.net> (Maintainer)