| From | Pasha Tatashin <> | Subject | [RFC 07/14] fork: use the first page in stack to store vm_stack in cached_stacks | Date | Mon, 11 Mar 2024 16:46:31 +0000 |
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vmap stack are stored in a per-cpu cache_stacks in order to reduce number of allocations and free calls. However, the stacks ared stored using the buttom address of the stack. Since stacks normally grow down, this is a problem with dynamic stacks, as the lower pages might not even be allocated. Instead of the first available page from vm_area.
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> --- kernel/fork.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/fork.c b/kernel/fork.c index 41e0baee79d2..3004e6ce6c65 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -217,9 +217,10 @@ static void thread_stack_free_rcu(struct rcu_head *rh) static void thread_stack_delayed_free(struct task_struct *tsk) { - struct vm_stack *vm_stack = tsk->stack; + struct vm_struct *vm_area = tsk->stack_vm_area; + struct vm_stack *vm_stack = page_address(vm_area->pages[0]); - vm_stack->stack_vm_area = tsk->stack_vm_area; + vm_stack->stack_vm_area = vm_area; call_rcu(&vm_stack->rcu, thread_stack_free_rcu); } -- 2.44.0.278.ge034bb2e1d-goog
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