linux.git/mm/rmap.c, branch v2.6.14

[PATCH] mm: cleanup rmap

2005-09-05T07:05:43+00:00

Thanks to Bill Irwin for pointing this out.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: micro-optimise rmap

2005-09-05T07:05:43+00:00

Microoptimise page_add_anon_rmap.  Although these expressions are used only in
the taken branch of the if() statement, the compiler can't reorder them inside
because atomic_inc_and_test is a barrier.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: comment rmap

2005-09-05T07:05:43+00:00

Just be clear that VM_RESERVED pages here are a bug, and the test is not there
because they are expected.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] rmap: don't test rss

2005-09-05T07:05:42+00:00

Remove the three get_mm_counter(mm, rss) tests from rmap.c: there was a
time when testing rss was important to avoid a particular race between
dup_mmap and the anonmm rmap; but now it's just a rather silly pseudo-
optimization, made even more obscure by the get_mm_counter macro.

Signed-off-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] swap: swap_lock replace list+device

2005-09-05T07:05:42+00:00

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 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] xip: fs/mm: execute in place

2005-06-24T07:06:41+00:00

- generic_file* file operations do no longer have a xip/non-xip split
- filemap_xip.c implements a new set of fops that require get_xip_page
  aop to work proper. all new fops are exported GPL-only (don't like to
  see whatever code use those except GPL modules)
- __xip_unmap now uses page_check_address, which is no longer static
  in rmap.c, and defined in linux/rmap.h
- mm/filemap.h is now much more clean, plainly having just Linus'
  inline funcs moved here from filemap.c
- fix includes in filemap_xip to make it build cleanly on i386

Signed-off-by: Carsten Otte 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] can_share_swap_page: use page_mapcount

2005-06-22T01:46:21+00:00

Remember that ironic get_user_pages race?  when the raised page_count on a
page swapped out led do_wp_page to decide that it had to copy on write, so
substituted a different page into userspace.  2.6.7 onwards have Andrea's
solution, where try_to_unmap_one backs out if it finds page_count raised.

Which works, but is unsatisfying (rmap.c has no other page_count heuristics),
and was found a few months ago to hang an intensive page migration test.  A
year ago I was hesitant to engage page_mapcount, now it seems the right fix.

So remove the page_count hack from try_to_unmap_one; and use activate_page in
unuse_mm when dropping lock, to replace its secondary effect of helping
swapoff to make progress in that case.

Simplify can_share_swap_page (now called only on anonymous pages) to check
page_mapcount + page_swapcount == 1: still needs the page lock to stabilize
their (pessimistic) sum, but does not need swapper_space.tree_lock for that.

In do_swap_page, move swap_free and unlock_page below page_add_anon_rmap, to
keep sum on the high side, and correct when can_share_swap_page called.

Signed-off-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] try_to_unmap_cluster() passes out-of-bounds pte to pte_unmap()

2005-05-25T03:08:13+00:00

try_to_unmap_cluster() does:
        for (pte = pte_offset_map(pmd, address);
                        address < end; pte++, address += PAGE_SIZE) {
		...
	}

	pte_unmap(pte);

It may take a little staring to notice, but pte can actually fall off the
end of the pte page in this iteration, which makes life difficult for
kmap_atomic() and the users not expecting it to BUG().  Of course, we're
somewhat lucky in that arithmetic elsewhere in the function guarantees that
at least one iteration is made, lest this force larger rearrangements to be
made.  This issue and patch also apply to non-mm mainline and with trivial
adjustments, at least two related kernels.

Discovered during internal testing at Oracle.

Signed-off-by: William Irwin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: fix rss counter being incremented when unmapping

2005-05-17T14:59:12+00:00

This patch fixes a bug introduced by the "mm counter operations through
macros" patch, which replaced a decrement operation in with an increment
macro in try_to_unmap_one().

Signed-off-by: Bj�rn Steinbrink 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: rmap.c cleanup

2005-05-01T15:58:36+00:00

mm/rmap.c:page_referenced_one() and mm/rmap.c:try_to_unmap_one() contain
identical code that

 - takes mm->page_table_lock;

 - drills through page tables;

 - checks that correct pte is reached.

Coalesce this into page_check_address()

Signed-off-by: Nikita Danilov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds