Hi Dan,
Today's linux-next merge of the cleancache tree got a conflict in
mm/Kconfig between various transparent huge page commits from Linus' tree
and commit 83137a5649ec8a0bb769c68024b0532733087482 ("mm: cleancache core
ops functions and config") from the cleancache tree.
Just context changes. I fixed it up (see below) and can carry the fix as
necessary.
--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
diff --cc mm/Kconfig
index 3ad483b,9ee0751..0000000
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@@ -302,48 -302,24 +302,70 @@@ config NOMMU_INITIAL_TRIM_EXCES
See Documentation/nommu-mmap.txt for more information.
+config TRANSPARENT_HUGEPAGE
+ bool "Transparent Hugepage Support"
+ depends on X86 && MMU
+ select COMPACTION
+ help
+ Transparent Hugepages allows the kernel to use huge pages and
+ huge tlb transparently to the applications whenever possible.
+ This feature can improve computing performance to certain
+ applications by speeding up page faults during memory
+ allocation, by reducing the number of tlb misses and by speeding
+ up the pagetable walking.
+
+ If memory constrained on embedded, you may want to say N.
+
+choice
+ prompt "Transparent Hugepage Support sysfs defaults"
+ depends on TRANSPARENT_HUGEPAGE
+ default TRANSPARENT_HUGEPAGE_ALWAYS
+ help
+ Selects the sysfs defaults for Transparent Hugepage Support.
+
+ config TRANSPARENT_HUGEPAGE_ALWAYS
+ bool "always"
+ help
+ Enabling Transparent Hugepage always, can increase the
+ memory footprint of applications without a guaranteed
+ benefit but it will work automatically for all applications.
+
+ config TRANSPARENT_HUGEPAGE_MADVISE
+ bool "madvise"
+ help
+ Enabling Transparent Hugepage madvise, will only provide a
+ performance improvement benefit to the applications using
+ madvise(MADV_HUGEPAGE) but it won't risk to increase the
+ memory footprint of applications without a guaranteed
+ benefit.
+endchoice
+
+#
+# UP and nommu archs use km based percpu allocator
+#
+config NEED_PER_CPU_KM
+ depends on !SMP
+ bool
+ default y
++
+ config CLEANCACHE
+ bool "Enable cleancache pseudo-RAM driver to cache clean pages"
+ default y
+ 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 put
+ it into a synchronous concurrency-safe page-oriented pseudo-RAM
+ device (such as Xen's Transcendent Memory, aka "tmem") which 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 pseudo-RAM device is available, 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
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