Introducing NR_VMAP_STACK_CACHE, the number of cached stacks for virtually mapped kernel stack can be configurable using Kbuild system. default value is 2.
Signed-off-by: Hoeun Ryu <[email protected]> --- arch/Kconfig | 8 ++++++++ kernel/fork.c | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/Kconfig b/arch/Kconfig index d49a8e6..066d111 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -849,6 +849,14 @@ config VMAP_STACK the stack to map directly to the KASAN shadow map using a formula that is incorrect if the stack is in vmalloc space. +config NR_VMAP_STACK_CACHE + int "Number of cached stacks" + default "2" + depends on VMAP_STACK + help + This determines how many stacks can be cached for virtually + mapped kernel stacks. + config ARCH_WANT_RELAX_ORDER bool diff --git a/kernel/fork.c b/kernel/fork.c index 7911ed2..73ba1da 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -166,7 +166,7 @@ void __weak arch_release_thread_stack(unsigned long *stack) * vmalloc() is a bit slow, and calling vfree() enough times will force a TLB * flush. Try to minimize the number of calls by caching stacks. */ -#define NR_CACHED_STACKS 2 +#define NR_CACHED_STACKS CONFIG_NR_VMAP_STACK_CACHE static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); #endif -- 2.7.4
