> On Feb 11, 2017, at 5:31 PM, Thomas Gleixner <[email protected]> wrote: > >> On Sat, 11 Feb 2017, Hoeun Ryu wrote: >> #define NR_CACHED_STACKS 2 >> static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); >> + >> +static int free_vm_stack_cache(unsigned int cpu) >> +{ >> + struct vm_struct **cached_vm_stacks = per_cpu_ptr(cached_stacks, cpu); >> + int i; >> + >> + for (i = 0; i < NR_CACHED_STACKS; i++) { >> + struct vm_struct *vm_stack = cached_vm_stacks[i]; >> + >> + if (!vm_stack) >> + continue; >> + >> + vfree(vm_stack->addr); >> + cached_vm_stacks[i] = NULL; >> + } >> + >> + return 0; >> +} >> #endif >> >> static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int >> node) >> @@ -456,6 +474,11 @@ void __init fork_init(void) >> for (i = 0; i < UCOUNT_COUNTS; i++) { >> init_user_ns.ucount_max[i] = max_threads/2; >> } >> + >> +#ifdef CONFIG_VMAP_STACK >> + cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vmstack_cache", >> + NULL, free_vm_stack_cache); >> +#endif > > If you wrap that in vm_stack_cache_init() and have a stub for !VMAP_STACK > (add an #else to the #ifdef VMAP_STACK section above) then you spare the > ugly ifdef in fork_init()
OK. I will. > Thanks, > > tglx
