linux.git/mm/rmap.c, branch v3.14

mm: fix swapops.h:131 bug if remap_file_pages raced migration

2014-03-21T05:09:09+00:00

Add remove_linear_migration_ptes_from_nonlinear(), to fix an interesting
little include/linux/swapops.h:131 BUG_ON(!PageLocked) found by trinity:
indicating that remove_migration_ptes() failed to find one of the
migration entries that was temporarily inserted.

The problem comes from remap_file_pages()'s switch from vma_interval_tree
(good for inserting the migration entry) to i_mmap_nonlinear list (no good
for locating it again); but can only be a problem if the remap_file_pages()
range does not cover the whole of the vma (zap_pte() clears the range).

remove_migration_ptes() needs a file_nonlinear method to go down the
i_mmap_nonlinear list, applying linear location to look for migration
entries in those vmas too, just in case there was this race.

The file_nonlinear method does need rmap_walk_control.arg to do this;
but it never needed vma passed in - vma comes from its own iteration.

Reported-and-tested-by: Dave Jones 
Reported-and-tested-by: Sasha Levin 
Signed-off-by: Hugh Dickins 
Signed-off-by: Linus Torvalds

mm/rmap: fix coccinelle warnings

2014-01-24T00:36:53+00:00

mm/rmap.c:851:9-10: WARNING: return of 0/1 in function 'invalid_mkclean_vma' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.

Generated by: coccinelle/misc/boolreturn.cocci

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

mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE

2014-01-24T00:36:50+00:00

Most of the VM_BUG_ON assertions are performed on a page.  Usually, when
one of these assertions fails we'll get a BUG_ON with a call stack and
the registers.

I've recently noticed based on the requests to add a small piece of code
that dumps the page to various VM_BUG_ON sites that the page dump is
quite useful to people debugging issues in mm.

This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what
VM_BUG_ON() does, also dumps the page before executing the actual
BUG_ON.

[akpm@linux-foundation.org: fix up includes]
Signed-off-by: Sasha Levin 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: use rmap_walk() in page_mkclean()

2014-01-22T00:19:46+00:00

Now, we have an infrastructure in rmap_walk() to handle difference from
   variants of rmap traversing functions.

So, just use it in page_mkclean().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
    cf> page_mkclean_file
2. mechanical change to use rmap_walk() in page_mkclean().

Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: use rmap_walk() in page_referenced()

2014-01-22T00:19:45+00:00

Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in page_referenced().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
	cf> page_referenced_ksm, page_referenced_anon,
	page_referenced_file

2. introduce new struct page_referenced_arg and pass it to
   page_referenced_one(), main function of rmap_walk, in order to count
   reference, to store vm_flags and to check finish condition.

3. mechanical change to use rmap_walk() in page_referenced().

[liwanp@linux.vnet.ibm.com: fix BUG at rmap_walk]
Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Wanpeng Li 
Cc: Sasha Levin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: use rmap_walk() in try_to_munlock()

2014-01-22T00:19:45+00:00

Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in try_to_munlock().

In this patch, I change following things.

1. remove some variants of rmap traversing functions.
	cf> try_to_unmap_ksm, try_to_unmap_anon, try_to_unmap_file
2. mechanical change to use rmap_walk() in try_to_munlock().
3. copy and paste comments.

Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: use rmap_walk() in try_to_unmap()

2014-01-22T00:19:45+00:00

Now, we have an infrastructure in rmap_walk() to handle difference from
variants of rmap traversing functions.

So, just use it in try_to_unmap().

In this patch, I change following things.

1. enable rmap_walk() if !CONFIG_MIGRATION.
2. mechanical change to use rmap_walk() in try_to_unmap().

Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: extend rmap_walk_xxx() to cope with different cases

2014-01-22T00:19:45+00:00

There are a lot of common parts in traversing functions, but there are
also a little of uncommon parts in it.  By assigning proper function
pointer on each rmap_walker_control, we can handle these difference
correctly.

Following are differences we should handle.

1. difference of lock function in anon mapping case
2. nonlinear handling in file mapping case
3. prechecked condition:
	checking memcg in page_referenced(),
	checking VM_SHARE in page_mkclean()
	checking temporary vma in try_to_unmap()
4. exit condition:
	checking page_mapped() in try_to_unmap()

So, in this patch, I introduce 4 function pointers to handle above
differences.

Signed-off-by: Joonsoo Kim 
Cc: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: make rmap_walk to get the rmap_walk_control argument

2014-01-22T00:19:45+00:00

In each rmap traverse case, there is some difference so that we need
function pointers and arguments to them in order to handle these

For this purpose, struct rmap_walk_control is introduced in this patch,
and will be extended in following patch.  Introducing and extending are
separate, because it clarify changes.

Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/rmap: factor lock function out of rmap_walk_anon()

2014-01-22T00:19:45+00:00

When we traverse anon_vma, we need to take a read-side anon_lock.  But
there is subtle difference in the situation so that we can't use same
method to take a lock in each cases.  Therefore, we need to make
rmap_walk_anon() taking difference lock function.

This patch is the first step, factoring lock function for anon_lock out
of rmap_walk_anon().  It will be used in case of removing migration
entry and in default of rmap_walk_anon().

Signed-off-by: Joonsoo Kim 
Reviewed-by: Naoya Horiguchi 
Cc: Mel Gorman 
Cc: Hugh Dickins 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Cc: Hillf Danton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds