Commit f1c1a9ee authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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fork: Move memcg_charge_kernel_stack() into CONFIG_VMAP_STACK 



memcg_charge_kernel_stack() is only used in the CONFIG_VMAP_STACK case.

Move memcg_charge_kernel_stack() into the CONFIG_VMAP_STACK block and
invoke it from within alloc_thread_stack_node().

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20220217102406.3697941-6-bigeasy@linutronix.de
parent 7865aba3

kernel/fork.c

+36 −33
Original line number Diff line number Diff line
@@ -211,6 +211,32 @@ static int free_vm_stack_cache(unsigned int cpu) 
	return 0;

}



static int memcg_charge_kernel_stack(struct task_struct *tsk)

{

	struct vm_struct *vm = task_stack_vm_area(tsk);

	int i;

	int ret;



	BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);

	BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);



	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {

		ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);

		if (ret)

			goto err;

	}

	return 0;

err:

	/*

	 * If memcg_kmem_charge_page() fails, page's memory cgroup pointer is

	 * NULL, and memcg_kmem_uncharge_page() in free_thread_stack() will

	 * ignore this page.

	 */

	for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)

		memcg_kmem_uncharge_page(vm->pages[i], 0);

	return ret;

}



static int alloc_thread_stack_node(struct task_struct *tsk, int node)

{

	void *stack;
@@ -230,6 +256,11 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node) 
		/* Clear stale pointers from reused stack. */

		memset(s->addr, 0, THREAD_SIZE);



		if (memcg_charge_kernel_stack(tsk)) {

			vfree(s->addr);

			return -ENOMEM;

		}



		tsk->stack_vm_area = s;

		tsk->stack = s->addr;

		return 0;
@@ -247,6 +278,11 @@ static int alloc_thread_stack_node(struct task_struct *tsk, int node) 
				     0, node, __builtin_return_address(0));

	if (!stack)

		return -ENOMEM;



	if (memcg_charge_kernel_stack(tsk)) {

		vfree(stack);

		return -ENOMEM;

	}

	/*

	 * We can't call find_vm_area() in interrupt context, and

	 * free_thread_stack() can be called in interrupt context,
@@ -418,36 +454,6 @@ static void account_kernel_stack(struct task_struct *tsk, int account) 
	}

}



static int memcg_charge_kernel_stack(struct task_struct *tsk)

{

#ifdef CONFIG_VMAP_STACK

	struct vm_struct *vm = task_stack_vm_area(tsk);

	int ret;



	BUILD_BUG_ON(IS_ENABLED(CONFIG_VMAP_STACK) && PAGE_SIZE % 1024 != 0);



	if (vm) {

		int i;



		BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);



		for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {

			/*

			 * If memcg_kmem_charge_page() fails, page's

			 * memory cgroup pointer is NULL, and

			 * memcg_kmem_uncharge_page() in free_thread_stack()

			 * will ignore this page.

			 */

			ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL,

						     0);

			if (ret)

				return ret;

		}

	}

#endif

	return 0;

}



static void release_task_stack(struct task_struct *tsk)

{

	if (WARN_ON(READ_ONCE(tsk->__state) != TASK_DEAD))
@@ -909,9 +915,6 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) 
	if (err)

		goto free_tsk;



	if (memcg_charge_kernel_stack(tsk))

		goto free_stack;



#ifdef CONFIG_THREAD_INFO_IN_TASK

	refcount_set(&tsk->stack_refcount, 1);

#endif