Re: [RFC] mm: generic adaptive large memory allocation APIs

From: Tetsuo Handa
Date: Fri May 07 2010 - 08:42:26 EST


Changli Gao wrote:
> static void __kvfree(void *ptr, bool inatomic)

inatomic might be confusing because what vfree() checks is
BUG_ON(in_interrupt()) rather than BUG_ON(in_atomic()).

> {
> if (unlikely(ZERO_OR_NULL_PTR(ptr)))
> return;
> if (is_vmalloc_addr(ptr)) {
> if (inatomic) {

By the way, is in_interrupt() a heavy operation?

register unsigned long current_stack_pointer asm("esp") __used;
static inline struct thread_info *current_thread_info(void)
{
return (struct thread_info *)
(current_stack_pointer & ~(THREAD_SIZE - 1));
}
#define preempt_count() (current_thread_info()->preempt_count)
#define irq_count() (preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK | NMI_MASK))
#define in_interrupt() (irq_count())

If we can agree on changing from (inatomic) to (in_interrupt()),
we can merge kvfree() and kvfree_inatomic().

> struct work_struct *work;
>
> work = ptr;
> BUILD_BUG_ON(sizeof(struct work_struct) > PAGE_SIZE);
> INIT_WORK(work, kvfree_work);
> schedule_work(work);
> } else {
> vfree(ptr);
> }
> } else {
> struct page *page;
>
> page = virt_to_head_page(ptr);
> if (PageSlab(page) || PageCompound(page))
> kfree(ptr);
> else
> free_pages_exact(ptr, page->private);
> }
> }
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