Re: [PATCH next/mmotm] swap: add per-partition lock for swapfile fix

Shaohua Li
2013-01-28T00:07:35Z

On Sun, Jan 27, 2013 at 01:47:01PM -0800, Hugh Dickins wrote:
> I had all cpus spinning in swap_info_get(), for the lock on an area
> being swapped off: probably because get_swap_page() forgot to unlock.
>
> Signed-off-by: Hugh Dickins <hughd@google.com>

Good catch. Thanks!

> ---
>
> mm/swapfile.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> --- mmotm.orig/mm/swapfile.c 2013-01-23 17:55:39.132447115 -0800
> +++ mmotm/mm/swapfile.c 2013-01-27 10:41:45.000000000 -0800
> @@ -470,10 +470,9 @@ swp_entry_t get_swap_page(void)
> spin_unlock(&swap_lock);
> /* This is called for allocating swap entry for cache */
> offset = scan_swap_map(si, SWAP_HAS_CACHE);
> - if (offset) {
> - spin_unlock(&si->lock);
> + spin_unlock(&si->lock);
> + if (offset)
> return swp_entry(type, offset);
> - }
> spin_lock(&swap_lock);
> next = swap_list.next;
> }