--- v11
+++ v8
@@ -2,52 +2,30 @@
handle speculative page fault.
By default it is turned off, and activated depending on architecture
-support, ARCH_HAS_PTE_SPECIAL, SMP and MMU.
-
-The architecture support is needed since the speculative page fault handler
-is called from the architecture's page faulting code, and some code has to
-be added there to handle the speculative handler.
-
-The dependency on ARCH_HAS_PTE_SPECIAL is required because vm_normal_page()
-does processing that is not compatible with the speculative handling in the
-case ARCH_HAS_PTE_SPECIAL is not set.
+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 1d0888c5b97a..a38796276113 100644
+index c782e8fb7235..42be0d92336e 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
-@@ -761,3 +761,25 @@ config GUP_BENCHMARK
+@@ -760,3 +760,6 @@ config GUP_BENCHMARK
+ performance of get_user_pages_fast().
- config ARCH_HAS_PTE_SPECIAL
- bool
-+
-+config ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
-+ def_bool n
+ See tools/testing/selftests/vm/gup_benchmark.c
+
+config SPECULATIVE_PAGE_FAULT
-+ bool "Speculative page faults"
-+ default y
-+ depends on ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT
-+ depends on ARCH_HAS_PTE_SPECIAL && 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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