On Sun, Mar 17, 2024 at 10:45 AM Christophe JAILLET
<christophe.jaillet@xxxxxxxxxx> wrote:
>
> Le 11/03/2024 à 17:46, Pasha Tatashin a écrit :
> > In many places number of pages in the stack is detremined via
> > (THREAD_SIZE / PAGE_SIZE). There is also a BUG_ON() that ensures that
> > (THREAD_SIZE / PAGE_SIZE) is indeed equals to vm_area->nr_pages.
> >
> > However, with dynamic stacks, the number of pages in vm_area will grow
> > with stack, therefore, use vm_area->nr_pages to determine the actual
> > number of pages allocated in stack.
> >
> > Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
> > ---
> > kernel/fork.c | 18 +++++++++---------
> > 1 file changed, 9 insertions(+), 9 deletions(-)
> >
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 60e812825a7a..a35f4008afa0 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -243,13 +243,11 @@ static int free_vm_stack_cache(unsigned int cpu)
> >
> > static int memcg_charge_kernel_stack(struct vm_struct *vm)
>
> Maybe s/vm/vm_area/ as done in 03/14?
Yes, I will add it to 03/14.
Thank you,
Pasha
>
> CJ
>
> > {
> > - int i;
> > - int ret;
> > + int i, ret, nr_pages;
> > int nr_charged = 0;
> >
> > - BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
> > -
> > - for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++) {
> > + nr_pages = vm->nr_pages;
> > + for (i = 0; i < nr_pages; i++) {
> > ret = memcg_kmem_charge_page(vm->pages[i], GFP_KERNEL, 0);
> > if (ret)
> > goto err;
> > @@ -531,9 +529,10 @@ static void account_kernel_stack(struct task_struct *tsk, int account)
> > {
> > if (IS_ENABLED(CONFIG_VMAP_STACK)) {
> > struct vm_struct *vm = task_stack_vm_area(tsk);
> > - int i;
> > + int i, nr_pages;
> >
> > - for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
> > + nr_pages = vm->nr_pages;
> > + for (i = 0; i < nr_pages; i++)
> > mod_lruvec_page_state(vm->pages[i], NR_KERNEL_STACK_KB,
> > account * (PAGE_SIZE / 1024));
> > } else {
> > @@ -551,10 +550,11 @@ void exit_task_stack_account(struct task_struct *tsk)
> >
> > if (IS_ENABLED(CONFIG_VMAP_STACK)) {
> > struct vm_struct *vm;
> > - int i;
> > + int i, nr_pages;
> >
> > vm = task_stack_vm_area(tsk);
> > - for (i = 0; i < THREAD_SIZE / PAGE_SIZE; i++)
> > + nr_pages = vm->nr_pages;
> > + for (i = 0; i < nr_pages; i++)
> > memcg_kmem_uncharge_page(vm->pages[i], 0);
> > }
> > }
>
