--- v10
+++ v8
@@ -2,44 +2,30 @@
handle speculative page fault.
By default it is turned off, and activated depending on architecture
-support, SMP and MMU.
+support.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
-Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
- mm/Kconfig | 22 ++++++++++++++++++++++
- 1 file changed, 22 insertions(+)
+ mm/Kconfig | 3 +++
+ 1 file changed, 3 insertions(+)
diff --git a/mm/Kconfig b/mm/Kconfig
-index d5004d82a1d6..5484dca11199 100644
+index c782e8fb7235..42be0d92336e 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
-@@ -752,3 +752,25 @@ config GUP_BENCHMARK
+@@ -760,3 +760,6 @@ config GUP_BENCHMARK
performance of get_user_pages_fast().
See tools/testing/selftests/vm/gup_benchmark.c
+
-+config ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
-+ def_bool n
-+
+config SPECULATIVE_PAGE_FAULT
-+ bool "Speculative page faults"
-+ default y
-+ depends on ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
-+ depends on MMU && SMP
-+ help
-+ Try to handle user space page faults without holding the mmap_sem.
-+
-+ This should allow better concurrency for massively threaded process
-+ since the page fault handler will not wait for other threads memory
-+ layout change to be done, assuming that this change is done in another
-+ part of the process's memory space. This type of page fault is named
-+ speculative page fault.
-+
-+ If the speculative page fault fails because of a concurrency is
-+ detected or because underlying PMD or PTE tables are not yet
-+ allocating, it is failing its processing and a classic page fault
-+ is then tried.
++ bool
--
2.7.4
+
+--
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