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charset="UTF-8" X-Rspam-User: X-Stat-Signature: kixj8cuaxz7qmkf45s3uz4s43z7q3sk5 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: A6A9818000B X-HE-Tag: 1790617322-283539 X-HE-Meta: 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 i8BTLBeu 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: David Stevens For vmap stacks not immediately released into the stack cache, free them in a workqueue instead of via call_rcu(). In an RCU context, vfree already schedules the actual freeing on the per-cpu system workqueue, so this change only affects when exactly the second attempt to put the stack into the stack cache occurs. Moving freeing to a workqueue will allow for freeing partially populated stacks in a sleepable context (for remove_vm_area), rather than relying on vfree dispatching to a workqueue via vfree_atomic. Signed-off-by: David Stevens [Use system_percpu_wq instead of system_wq as it is deprecated and update commit msg] Signed-off-by: Mostafa Saleh --- kernel/fork.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/fork.c b/kernel/fork.c index 3f1c46d8f7ec..ca8e68882316 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -208,7 +208,7 @@ static DEFINE_PER_CPU(struct vm_struct *, cached_stacks[NR_CACHED_STACKS]); #define GFP_VMAP_STACK (GFP_KERNEL | __GFP_ZERO | __GFP_SKIP_KASAN) struct vm_stack { - struct rcu_head rcu; + struct rcu_work work; struct vm_struct *stack_vm_area; }; @@ -287,9 +287,9 @@ static inline void free_vmap_stack(struct vm_struct *vm_area) vfree(vm_area->addr); } -static void thread_stack_free_rcu(struct rcu_head *rh) +static void thread_stack_free_work(struct work_struct *work) { - struct vm_stack *vm_stack = container_of(rh, struct vm_stack, rcu); + struct vm_stack *vm_stack = container_of(to_rcu_work(work), struct vm_stack, work); struct vm_struct *vm_area = vm_stack->stack_vm_area; if (try_release_thread_stack_to_cache(vm_stack->stack_vm_area)) @@ -308,7 +308,8 @@ static void thread_stack_delayed_free(struct task_struct *tsk) vm_stack = tsk->stack + THREAD_SIZE - sizeof(*vm_stack); vm_stack->stack_vm_area = tsk->stack_vm_area; - call_rcu(&vm_stack->rcu, thread_stack_free_rcu); + INIT_RCU_WORK(&vm_stack->work, thread_stack_free_work); + queue_rcu_work(system_percpu_wq, &vm_stack->work); } static int free_vm_stack_cache(unsigned int cpu) -- 2.56.0.rc1.315.gc6ed9934b7-goog