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/filemap.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/filemap.c')
| -rw-r--r-- | mm/filemap.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index c11418dd94e8..edc54436fa94 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -54,9 +54,8 @@ * * ->i_mmap_lock (vmtruncate) * ->private_lock (__free_pte->__set_page_dirty_buffers) - * ->swap_list_lock - * ->swap_device_lock (exclusive_swap_page, others) - * ->mapping->tree_lock + * ->swap_lock (exclusive_swap_page, others) + * ->mapping->tree_lock * * ->i_sem * ->i_mmap_lock (truncate->unmap_mapping_range) @@ -86,7 +85,7 @@ * ->page_table_lock (anon_vma_prepare and various) * * ->page_table_lock - * ->swap_device_lock (try_to_unmap_one) + * ->swap_lock (try_to_unmap_one) * ->private_lock (try_to_unmap_one) * ->tree_lock (try_to_unmap_one) * ->zone.lru_lock (follow_page->mark_page_accessed) |