diff options
| author | Hugh Dickins <hugh@veritas.com> | 2005-09-04 00:54:41 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 09:05:42 +0200 |
| commit | 5d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1 (patch) | |
| tree | 91ed9ef6f4cb5f6a1832f2baaaabd53fcd83513e /mm/rmap.c | |
| parent | [PATCH] swap: scan_swap_map latency breaks (diff) | |
| download | linux-5d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1.tar.xz linux-5d337b9194b1ce3b6fd5f3cb2799455ed2f9a3d1.zip | |
[PATCH] swap: swap_lock replace list+device
The idea of a swap_device_lock per device, and a swap_list_lock over them all,
is appealing; but in practice almost every holder of swap_device_lock must
already hold swap_list_lock, which defeats the purpose of the split.
The only exceptions have been swap_duplicate, valid_swaphandles and an
untrodden path in try_to_unuse (plus a few places added in this series).
valid_swaphandles doesn't show up high in profiles, but swap_duplicate does
demand attention. However, with the hold time in get_swap_pages so much
reduced, I've not yet found a load and set of swap device priorities to show
even swap_duplicate benefitting from the split. Certainly the split is mere
overhead in the common case of a single swap device.
So, replace swap_list_lock and swap_device_lock by spinlock_t swap_lock
(generally we seem to prefer an _ in the name, and not hide in a macro).
If someone can show a regression in swap_duplicate, then probably we should
add a hashlock for the swap_map entries alone (shorts being anatomic), so as
to help the case of the single swap device too.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/rmap.c')
| -rw-r--r-- | mm/rmap.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 08ac5c7fa91f..facb8cdca665 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -34,9 +34,8 @@ * anon_vma->lock * mm->page_table_lock * zone->lru_lock (in mark_page_accessed) - * swap_list_lock (in swap_free etc's swap_info_get) + * swap_lock (in swap_duplicate, swap_info_get) * mmlist_lock (in mmput, drain_mmlist and others) - * swap_device_lock (in swap_duplicate, swap_info_get) * mapping->private_lock (in __set_page_dirty_buffers) * inode_lock (in set_page_dirty's __mark_inode_dirty) * sb_lock (within inode_lock in fs/fs-writeback.c) |