Re: Minutes from Feb 21 LSE Call

William Lee Irwin III
2003-02-25T17:55:26Z

On Tue, Feb 25, 2003 at 09:43:59AM -0800, William Lee Irwin III wrote:
>> The pagetable cache is gone in 2.5, so pte_alloc_one() takes the
>> bitblitting hit for pagetables.

On Tue, Feb 25, 2003 at 06:59:28PM +0100, Andrea Arcangeli wrote:
> I'm talking about do_anonymous_page, do_wp_page, do_no_page fork and all
> the other places that introduces spinlocks (per-page) and allocations of
> 2 pieces of ram rather than just 1 (and in turn potentially global
> spinlocks too if the cpu-caches are empty). Just grep for
> pte_chain_alloc or page_add_rmap in mm/memory.c, that's what I mean, I'm
> not talking about pagetables.

Well, pte_alloc_one() has a clear explanation.

The fact that the rmap accounting is not free is not news.

For anonymous pages performing the analogous vma-based lookup as with
Dave McCracken's patch for file-backed pages would require a
significant anonymous page accounting rework.

-- wli