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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-26 10:50:56 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-05-26 10:50:56 -0700 |
| commit | f8d613e2a665bf1be9628a3c3f9bafe7599b32c0 (patch) | |
| tree | 98d4da8d0e1a5fb1d9064626b4b96d95ccf26375 /mm/Kconfig | |
| parent | 8a0599dd2471f2a2e409498c08a0ab339057ad06 (diff) | |
| parent | 5bc20fc59706214d9591c11e1938a629d3538c12 (diff) | |
| download | linux-f8d613e2a665bf1be9628a3c3f9bafe7599b32c0.tar.gz | |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem: xen: cleancache shim to Xen Transcendent Memory ocfs2: add cleancache support ext4: add cleancache support btrfs: add cleancache support ext3: add cleancache support mm/fs: add hooks to support cleancache mm: cleancache core ops functions and config fs: add field to superblock to support cleancache mm/fs: cleancache documentation Fix up trivial conflict in fs/btrfs/extent_io.c due to includes
Diffstat (limited to 'mm/Kconfig')
| -rw-r--r-- | mm/Kconfig | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index e9c0c61f2ddd..8ca47a5ee9c8 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -347,3 +347,26 @@ config NEED_PER_CPU_KM depends on !SMP bool default y + +config CLEANCACHE + bool "Enable cleancache driver to cache clean pages if tmem is present" + default n + help + Cleancache can be thought of as a page-granularity victim cache + for clean pages that the kernel's pageframe replacement algorithm + (PFRA) would like to keep around, but can't since there isn't enough + memory. So when the PFRA "evicts" a page, it first attempts to use + cleancacne code to put the data contained in that page into + "transcendent memory", memory that is not directly accessible or + addressable by the kernel and is of unknown and possibly + time-varying size. And when a cleancache-enabled + filesystem wishes to access a page in a file on disk, it first + checks cleancache to see if it already contains it; if it does, + the page is copied into the kernel and a disk access is avoided. + When a transcendent memory driver is available (such as zcache or + Xen transcendent memory), a significant I/O reduction + may be achieved. When none is available, all cleancache calls + are reduced to a single pointer-compare-against-NULL resulting + in a negligible performance hit. + + If unsure, say Y to enable cleancache |