Messages in this thread | | | Date | Sun, 17 Mar 2024 15:45:23 +0100 | Subject | Re: [RFC 04/14] fork: Remove assumption that vm_area->nr_pages equals to THREAD_SIZE | From | Christophe JAILLET <> |
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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@soleen.com> > --- > 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?
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); > } > }
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