mm: introduce CONFIG_PER_VMA_LOCK

This configuration variable will be used to build the support for VMA
locking during page fault handling.

This is enabled by default on supported architectures with SMP and MMU
set.

The architecture support is needed since the page fault handler is called
from the architecture's page faulting code which needs modifications to
handle faults under VMA lock.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>

diff --git a/mm/Kconfig b/mm/Kconfig
index 57e1d8c5b505287c3c0c81474d0daaa8f333e3d1..1f48e9f7c8fa685a995d00487e6b0a54fc403608 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1150,6 +1150,19 @@ config LRU_GEN_STATS
          This option has a per-memcg and per-node memory overhead.
 # }
 
+config ARCH_SUPPORTS_PER_VMA_LOCK
+       def_bool n
+
+config PER_VMA_LOCK
+       bool "Per-vma locking support"
+       default y
+       depends on ARCH_SUPPORTS_PER_VMA_LOCK && MMU && SMP
+       help
+         Allow per-vma locking during page fault handling.
+
+         This feature allows locking each virtual memory area separately when
+         handling page faults instead of taking mmap_lock.
+
 source "mm/damon/Kconfig"
 
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