atomic64_test: simplify the #ifdef for atomic64_dec_if_positive() test
Introduce CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE and use this instead
of the multitude of #if defined() checks in atomic64_test.c
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
When looking to fetch a node's sibling, we went through a sequence of:
- check if node is the parent's left child
- if it is, then fetch the parent's right child
This can be replaced with:
- fetch the parent's right child as an assumed sibling
- check that node is NOT the fetched child
This avoids fetching the parent's left child when node is actually
that child. Saves a bit on code size, though it doesn't seem to make
a large difference in speed.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minor updates to the rb_erase() function:
- Reorder code to put simplest / common case (no more than 1 child) first.
- Fetch the parent first, since it ends up being required in all 3 cases.
- Add a few comments to illustrate case 2 (node to remove has 2 childs,
but one of them is the successor) and case 3 (node to remove has 2 childs,
successor is a left-descendant of the right child).
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Set comment and indentation style to be consistent with linux coding style
and the rest of the file, as suggested by Peter Zijlstra
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: low level optimizations in __rb_erase_color()
In __rb_erase_color(), we often already have pointers to the nodes being
rotated and/or know what their colors must be, so we can generate more
efficient code than the generic __rb_rotate_left() and __rb_rotate_right()
functions.
Also when the current node is red or when flipping the sibling's color,
the parent is already known so we can use the more efficient
rb_set_parent_color() function to set the desired color.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: optimize case selection logic in __rb_erase_color()
In __rb_erase_color(), we have to select one of 3 cases depending on the
color on the 'other' node children. If both children are black, we flip a
few node colors and iterate. Otherwise, we do either one or two tree
rotations, depending on the color of the 'other' child opposite to 'node',
and then we are done.
The corresponding logic had duplicate checks for the color of the 'other'
child opposite to 'node'. It was checking it first to determine if both
children are black, and then to determine how many tree rotations are
required. Rearrange the logic to avoid that extra check.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: adjust node color in __rb_erase_color() only when necessary
In __rb_erase_color(), we were always setting a node to black after
exiting the main loop. And in one case, after fixing up the tree to
satisfy all rbtree invariants, we were setting the current node to root
just to guarantee a loop exit, at which point the root would be set to
black. However this is not necessary, as the root of an rbtree is already
known to be black. The only case where the color flip is required is when
we exit the loop due to the current node being red, and it's easiest to
just do the flip at that point instead of doing it after the loop.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: low level optimizations in rb_insert_color()
- Use the newly introduced rb_set_parent_color() function to flip the color
of nodes whose parent is already known.
- Optimize rb_parent() when the node is known to be red - there is no need
to mask out the color in that case.
- Flipping gparent's color to red requires us to fetch its rb_parent_color
field, so we can reuse it as the parent value for the next loop iteration.
- Do not use __rb_rotate_left() and __rb_rotate_right() to handle tree
rotations: we already have pointers to all relevant nodes, and know their
colors (either because we want to adjust it, or because we've tested it,
or we can deduce it as black due to the node proximity to a known red node).
So we can generate more efficient code by making use of the node pointers
we already have, and setting both the parent and color attributes for
nodes all at once. Also in Case 2, some node attributes don't have to
be set because we know another tree rotation (Case 3) will always follow
and override them.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: adjust root color in rb_insert_color() only when necessary
The root node of an rbtree must always be black. However,
rb_insert_color() only needs to maintain this invariant when it has been
broken - that is, when it exits the loop due to the current (red) node
being the root. In all other cases (exiting after tree rotations, or
exiting due to an existing black parent) the invariant is already
satisfied, so there is no need to adjust the root node color.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: break out of rb_insert_color loop after tree rotation
It is a well known property of rbtrees that insertion never requires more
than two tree rotations. In our implementation, after one loop iteration
identified one or two necessary tree rotations, we would iterate and look
for more. However at that point the node's parent would always be black,
which would cause us to exit the loop.
We can make the code flow more obvious by just adding a break statement
after the tree rotations, where we know we are done. Additionally, in the
cases where two tree rotations are necessary, we don't have to update the
'node' pointer as it wouldn't be used until the next loop iteration, which
we now avoid due to this break statement.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This small module helps measure the performance of rbtree insert and
erase.
Additionally, we run a few correctness tests to check that the rbtrees
have all desired properties:
- contains the right number of nodes in the order desired,
- never two consecutive red nodes on any path,
- all paths to leaf nodes have the same number of black nodes,
- root node is black
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Woodhouse [Sat, 21 Jul 2012 00:54:55 +0000 (10:54 +1000)]
rbtree: fix jffs2 build issue due to renamed __rb_parent_color field
... and clean up the comments to better explain why it's acceptable to
do it this way instead of using rb_erase() "properly".
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: move some implementation details from rbtree.h to rbtree.c
rbtree users must use the documented APIs to manipulate the tree
structure. Low-level helpers to manipulate node colors and parenthood are
not part of that API, so move them to lib/rbtree.c
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: fix incorrect rbtree node insertion in fs/proc/proc_sysctl.c
The recently added code to use rbtrees in sysctl did not follow the proper
rbtree interface on insertion - it was calling rb_link_node() which
inserts a new node into the binary tree, but missed the call to
rb_insert_color() which properly balances the rbtree and establishes all
expected rbtree invariants.
I found out about this only because faulty commit also used
rb_init_node(), which I am removing within this patchset. But I think
it's an easy mistake to make, and it makes me wonder if we should change
the rbtree API so that insertions would be done with a single rb_insert()
call (even if its implementation could still inline the rb_link_node()
part and call a private __rb_insert_color function to do the rebalancing).
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Empty nodes have no color. We can make use of this property to simplify
the code emitted by the RB_EMPTY_NODE and RB_CLEAR_NODE macros. Also, we
can get rid of the rb_init_node function which had been introduced by 88d19cf37952 ("timers: Add rb_init_node() to allow for stack allocated rb
nodes") to avoid some issue with the empty node's color not being
initialized.
I'm not sure what the RB_EMPTY_NODE checks in rb_prev() / rb_next() are
doing there, though. axboe introduced them in 10fd48f2376d ("rbtree:
fixed reversed RB_EMPTY_NODE and rb_next/prev"). The way I see it, the
'empty node' abstraction is only used by rbtree users to flag nodes that
they haven't inserted in any rbtree, so asking the predecessor or
successor of such nodes doesn't make any sense.
One final rb_init_node() caller was recently added in sysctl code to
implement faster sysctl name lookups. This code doesn't make use of
RB_EMPTY_NODE at all, and from what I could see it only called
rb_init_node() under the mistaken assumption that such initialization was
required before node insertion.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rbtree: reference Documentation/rbtree.txt for usage instructions
I recently started looking at the rbtree code (with an eye towards
improving the augmented rbtree support, but I haven't gotten there yet).
I noticed a lot of possible speed improvements, which I am now proposing
in this patch set.
Patches 1-4 are preparatory: remove internal functions from rbtree.h so
that users won't be tempted to use them instead of the documented APIs,
clean up some incorrect usages I've noticed (in particular, with the
recently added fs/proc/proc_sysctl.c rbtree usage), reference the
documentation so that people have one less excuse to miss it, etc.
Patch 5 is a small module I wrote to check the rbtree performance. It
creates 100 nodes with random keys and repeatedly inserts and erases them
from an rbtree. Additionally, it has code to check for rbtree invariants
after each insert or erase operation.
Patches 6-12 is where the rbtree optimizations are done, and they touch
only that one file, lib/rbtree.c . I am getting good results out of these
- in my small benchmark doing rbtree insertion (including search) and
erase, I'm seeing a 30% runtime reduction on Sandybridge E5, which is more
than I initially thought would be possible. (the results aren't as
impressive on my two other test hosts though, AMD barcelona and Intel
Westmere, where I am seeing 14% runtime reduction only). The code size -
both source (ommiting comments) and compiled - is also shorter after these
changes. However, I do admit that the updated code is more arduous to
read - one big reason for that is the removal of the tree rotation
helpers, which added some overhead but also made it easier to reason about
things locally. Overall, I believe this is an acceptable compromise,
given that this code doesn't get modified very often, and that I have good
tests for it.
Upon Peter's suggestion, I added comments showing the rtree configuration
before every rotation. I think they help; however it's still best to have
a copy of the cormen/leiserson/rivest book when digging into this code.
This patch: reference Documentation/rbtree.txt for usage instructions
include/linux/rbtree.h included some basic usage instructions, while
Documentation/rbtree.txt had some more complete and easier to follow
instructions. Replacing the former with a reference to the latter.
Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: David Woodhouse <David.Woodhouse@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
d6629859 ("ipc/mqueue: improve performance of send/recv") and ce2d52cc
("ipc/mqueue: add rbtree node caching support") introduced an rbtree of
message priorities, and usage of rb_init_node() to initialize the
corresponding nodes. As it turns out, rb_init_node() is unnecessary here,
as the nodes are fully initialized on insertion by rb_link_node() and the
code doesn't access nodes that aren't inserted on the rbtree.
Removing the rb_init_node() calls as I removed that function during
rbtree API cleanups (the only other use of it was in a place that similarly
didn't require it).
Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:54 +0000 (10:54 +1000)]
ext4: use memweight()
Convert ext4_count_free() to use memweight() instead of table lookup based
counting clear bits implementation. This change only affects the code
segments enabled by EXT4FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is aligned
to long-word boundary. Because the size of the memory area may not be a
multiple of BITS_PER_LONG, then it returns wrong value on big-endian
architecture.
This also includes the following change.
- Remove unnecessary map == NULL check in ext4_count_free() which
always takes non-null pointer as the memory area.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:53 +0000 (10:54 +1000)]
ext3: use memweight()
Convert ext3_count_free() to use memweight() instead of table lookup based
counting clear bits implementation. This change only affects the code
segments enabled by EXT3FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is aligned
to long-word boundary. Because the size of the memory area may not be a
multiple of BITS_PER_LONG, then it returns wrong value on big-endian
architecture.
This also includes the following changes.
- Remove unnecessary map == NULL check in ext3_count_free() which
always takes non-null pointer as the memory area.
- Fix printk format warning that only reveals with EXT3FS_DEBUG.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:53 +0000 (10:54 +1000)]
ext2: use memweight()
Convert ext2_count_free() to use memweight() instead of table lookup based
counting clear bits implementation. This change only affects the code
segments enabled by EXT2FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is aligned
to long-word boundary. Because the size of the memory area may not be a
multiple of BITS_PER_LONG, then it returns wrong value on big-endian
architecture.
This also includes the following changes.
- Remove unnecessary map == NULL check in ext2_count_free() which
always takes non-null pointer as the memory area.
- Fix printk format warning that only reveals with EXT2FS_DEBUG.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:53 +0000 (10:54 +1000)]
ocfs2: use memweight()
Use memweight to count the total number of bits set in memory area.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:51 +0000 (10:54 +1000)]
qnx4fs: use memweight()
Use memweight() to count the total number of bits clear in memory area.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is aligned
to long-word boundary. Because the size of the memory area may not be a
multiple of BITS_PER_LONG, then it returns wrong value on big-endian
architecture.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Anders Larsen <al@alarsen.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:51 +0000 (10:54 +1000)]
string: fix build error caused by memweight() introduction
Tony Luck reports a build error on the ia64 sim_defconfig:
LD arch/ia64/hp/sim/boot/bootloader
lib/lib.a(string.o): In function `bitmap_weight':
.../linux-next/include/linux/bitmap.h:280: undefined reference to `__bitmap_weight'
It fails because it pulls in lib/lib.a(string.o) to get some
innocuous function like strcpy() ... but it also gets
given memweight() which relies on __bitmap_weight()
which it doesn't have, because it doesn't include lib/built-in.o
(which is where bitmap.o, the definer of __bitmap_weight(), has
been linked).
This build error is introduced by the patch string-introduce-memweight.patch
in -mm tree. Fix it by creating own file lib/memweight.c.
Reported-by: Tony Luck <tony.luck@gmail.com> Suggested-by: Tony Luck <tony.luck@gmail.com> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Akinobu Mita [Sat, 21 Jul 2012 00:54:50 +0000 (10:54 +1000)]
string: introduce memweight()
memweight() is the function that counts the total number of bits set in
memory area. Unlike bitmap_weight(), memweight() takes pointer and size
in bytes to specify a memory area which does not need to be aligned to
long-word boundary.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Anders Larsen <al@alarsen.net> Cc: Alasdair Kergon <agk@redhat.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:49 +0000 (10:54 +1000)]
backlight: l4f00242t03: export and use devm_gpio_request_one()
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_gpio_request_one() for these functions.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Cc: Alberto Panizzo <alberto@amarulasolutions.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:49 +0000 (10:54 +1000)]
backlight: corgi_lcd: use devm_gpio_request()
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_gpio_request() for these functions.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Cc: Eric Miao <eric.y.miao@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:49 +0000 (10:54 +1000)]
backlight: lms283gf05: use devm_gpio_request()
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_gpio_request() for these functions.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Marek Vasut <marek.vasut@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:48 +0000 (10:54 +1000)]
backlight: ot200_bl: use devm_gpio_request()
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_gpio_request() for these functions.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Christian Gmeiner <christian.gmeiner@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:47 +0000 (10:54 +1000)]
drivers/video/backlight/lm3533_bl.c: use devm_ functions
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_kzalloc of these functions.
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Acked-by: Johan Hovold <jhovold@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jingoo Han [Sat, 21 Jul 2012 00:54:47 +0000 (10:54 +1000)]
drivers/video/backlight/ot200_bl.c: use devm_ functions
The devm_ functions allocate memory that is released when a driver
detaches. This patch uses devm_kzalloc of these functions
Signed-off-by: Jingoo Han <jg1.han@samsung.com> Cc: Christian Gmeiner <christian.gmeiner@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The intent behind this behavior was to return "pK-error" in cases where
the %pK format specifier was used in interrupt context, because the
CAP_SYSLOG check wouldn't be meaningful. Clearly this should only apply
when kptr_restrict is actually enabled though.
Reported-by: Stevie Trujillo <stevie.trujillo@gmail.com> Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joe Perches [Sat, 21 Jul 2012 00:54:45 +0000 (10:54 +1000)]
printk: remove the now unnecessary "C" annotation for KERN_CONT
Now that all KERN_<LEVEL> uses are prefixed with ASCII SOH, there is no
need for a KERN_CONT. Keep it backward compatible by adding #define
KERN_CONT ""
Reduces kernel image size a thousand bytes.
Signed-off-by: Joe Perches <joe@perches.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Mason <chris.mason@oracle.com>
WARNING: static const char * array should probably be static const char * const
#95: FILE: fs/btrfs/super.c:170:
+static const char *logtypes[] = {
total: 0 errors, 1 warnings, 115 lines checked
./patches/btrfs-use-printk_get_level-and-printk_skip_level-add-__printf-fix-fallout.patch has style problems, please review.
If any of these errors are false positives, please report
them to the maintainer, see CHECKPATCH in MAINTAINERS.
Please run checkpatch prior to sending patches
Cc: Chris Mason <chris.mason@oracle.com> Cc: Joe Perches <joe@perches.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joe Perches [Sat, 21 Jul 2012 00:54:43 +0000 (10:54 +1000)]
btrfs: use printk_get_level and printk_skip_level, add __printf, fix fallout
Use the generic printk_get_level() to search a message for a kern_level.
Add __printf to verify format and arguments. Fix a few messages that had
mismatches in format and arguments. Add #ifdef CONFIG_PRINTK blocks to
shrink the object size a bit when not using printk.
Signed-off-by: Joe Perches <joe@perches.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joe Perches [Sat, 21 Jul 2012 00:54:43 +0000 (10:54 +1000)]
arch: remove direct definitions of KERN_<LEVEL> uses
Add #include <linux/kern_levels.h> so that the #define KERN_<LEVEL> macros
don't have to be duplicated.
Signed-off-by: Joe Perches <joe@perches.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Kay Sievers <kay@vrfy.org> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joe Perches [Sat, 21 Jul 2012 00:54:42 +0000 (10:54 +1000)]
printk: add generic functions to find KERN_<LEVEL> headers
The current form of a KERN_<LEVEL> is "<.>".
Add printk_get_level and printk_skip_level functions to handle these
formats.
These functions centralize tests of KERN_<LEVEL> so a future modification
can change the KERN_<LEVEL> style and shorten the number of bytes consumed
by these headers.
Signed-off-by: Joe Perches <joe@perches.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kay Sievers [Sat, 21 Jul 2012 00:54:41 +0000 (10:54 +1000)]
kmsg: /dev/kmsg - properly return possible copy_from_user() failure
Reported-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
NMI watchdog: fix for lockup detector breakage on resume
On the suspend/resume path the boot CPU does not go though an
offline->online transition. This breaks the NMI detector post-resume
since it depends on PMU state that is lost when the system gets suspended.
Fix this by forcing a CPU offline->online transition for the lockup
detector on the boot CPU during resume.
To provide more context, we enable NMI watchdog on Chrome OS. We have
seen several reports of systems freezing up completely which indicated
that the NMI watchdog was not firing for some reason.
Debugging further, we found a simple way of repro'ing system freezes --
issuing the command 'tasket 1 sh -c "echo nmilockup > /proc/breakme"'
after the system has been suspended/resumed one or more times.
With this patch in place, the system freeze result in panics, as expected.
These panics provide a nice stack trace for us to debug the actual issue
causing the freeze.
[akpm@linux-foundation.org: fiddle with code comment]
[akpm@linux-foundation.org: make lockup_detector_bootcpu_resume() conditional on CONFIG_SUSPEND]
[akpm@linux-foundation.org: fix section errors] Signed-off-by: Sameer Nanda <snanda@chromium.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Don Zickus <dzickus@redhat.com> Cc: Mandeep Singh Baines <msb@chromium.org> Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
panic_lock is meant to ensure that panic processing takes place only on
one cpu; if any of the other cpus encounter a panic, they will spin
waiting to be shut down.
However, this causes a regression in this scenario:
1. Cpu 0 encounters a panic and acquires the panic_lock
and proceeds with the panic processing.
2. There is an interrupt on cpu 0 that also encounters
an error condition and invokes panic.
3. This second invocation fails to acquire the panic_lock
and enters the infinite while loop in panic_smp_self_stop.
Thus all panic processing is stopped, and the cpu is stuck for eternity in
the while(1) inside panic_smp_self_stop.
To address this, disable local interrupts with local_irq_disable before
acquiring the panic_lock. This will prevent interrupt handlers from
executing during the panic processing, thus avoiding this particular
problem.
Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
clk_get() returns -ENOENT on error and some careless caller might
dereference it without error checking:
In mxc_rnga_remove():
struct clk *clk = clk_get(&pdev->dev, "rng");
// ...
clk_disable(clk);
Since it's insane to audit the lots of existing and future clk users,
let's add a check in the callee to avoid kernel panic and warn about
any buggy user.
Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Viresh Kumar <viresh.kumar@st.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
usb/host/r8a66597: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gadget/r8a66597: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
gadget/m66592: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
net/stmmac: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
This also fixes error paths of probe(), as a goto is required in this patch.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
net/c_can: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in clk.h,
there is no need to have clk code enclosed in #ifdef CONFIG_HAVE_CLK, #endif
macros.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Bhupesh Sharma <bhupesh.sharma@st.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
ata/pata_arasan: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Jeff Garzik <jgarzik@redhat.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
usb/musb: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
musb also has these dummy macros defined locally. Remove them as they
aren't required anymore.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
usb/marvell: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
Marvell usb also has these dummy macros defined locally. Remove them as
they aren't required anymore.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
i2c/i2c-pxa: remove conditional compilation of clk code
With addition of dummy clk_*() calls for non CONFIG_HAVE_CLK cases in
clk.h, there is no need to have clk code enclosed in #ifdef
CONFIG_HAVE_CLK, #endif macros.
pxa i2c also has these dummy macros defined locally. Remove them as they
aren't required anymore.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Many drivers are shared between architectures that may or may not have
HAVE_CLK selected for them. To remove compilation errors for them we
enclose clk_*() calls in these drivers within #ifdef CONFIG_HAVE_CLK,
#endif.
This patch removes the need of these CONFIG_HAVE_CLK statements, by
introducing dummy routines when HAVE_CLK is not selected by platforms.
So, definition of these routines will always be available. These calls
will return error for platforms that don't select HAVE_CLK.
Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Cc: Wolfram Sang <w.sang@pengutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jeff Garzik <jgarzik@redhat.com> Cc: Andrew Lunn <andrew@lunn.ch> Cc: Bhupesh Sharma <bhupesh.sharma@st.com> Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Mike Turquette <mturquette@linaro.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: viresh kumar <viresh.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kautuk Consul [Sat, 21 Jul 2012 00:54:36 +0000 (10:54 +1000)]
avr32/mm/fault.c: port OOM changes to do_page_fault
Commits d065bd810b6de ("mm: retry page fault when blocking on disk
transfer") and 37b23e0525d3 ("x86,mm: make pagefault killable") introduced
changes into the x86 pagefault handler for making the page fault handler
retryable as well as killable.
These changes reduce the mmap_sem hold time, which is crucial during OOM
killer invocation.
Port these changes to AVR32.
Signed-off-by: Mohd. Faris <mohdfarisq2010@gmail.com> Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Paul Bolle [Sat, 21 Jul 2012 00:54:36 +0000 (10:54 +1000)]
alpha: remove mysterious if zero-ed out includes
There's a small group of odd looking includes in smc37c669.c. These
includes appear to be if zero-ed out ever since they were added to the
tree (in v2.1.89). Their purpose is unclear to me. Perhaps they were
used in someones build system. Whatever their purpose was, nothing else
uses something comparable. This entire if zero-ed out block might as well
be removed.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 6afe1a1fe8ff83f6a ("PM: Remove legacy PM") removed the
initialization of retval, causing:
arch/frv/kernel/pm.c: In function 'sysctl_pm_do_suspend':
arch/frv/kernel/pm.c:165:5: warning: 'retval' may be used uninitialized in this function [-Wuninitialized]
Remove the variable completely to fix this, and convert to a proper
switch (...) { ... } construct to improve readability.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The tmpfs superblock grants an offset for each inode as they are created.
Each inode then uses that offset to provide a preferred first node for its
interleave in the newly provided shmem_interleave.
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Cc: Christoph Lameter <cl@linux.com> Cc: Nick Piggin <npiggin@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
shmem: provide vm_ops when also providing a mem policy
When tmpfs has the memory policy interleaved it always starts allocating
for each file at node 0. When there are many small files the lower nodes
fill up disproportionately.
This patchset spreads out node usage by starting files at nodes other then
0. The tmpfs superblock grants an offset for each inode as they are
created. Each then uses that offset to proved a prefered first node for
its interleave in the shmem_interleave.
This patch:
Update shmem_get_policy() to use the vma_policy if provided. This is to
allows us to safely provide shmem_vm_ops to the vma when the vm_file has
not been setup which is the case on the pseudo vmas.
Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Cc: Christoph Lameter <cl@linux.com> Cc: Nick Piggin <npiggin@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
memcg: further prevent OOM with too many dirty pages
The may_enter_fs test turns out to be too restrictive: though I saw no
problem with it when testing on 3.5-rc6, it very soon OOMed when I tested
on 3.5-rc6-mm1. I don't know what the difference there is, perhaps I just
slightly changed the way I started off the testing: dd if=/dev/zero
of=/mnt/temp bs=1M count=1024; rm -f /mnt/temp; sync repeatedly, in 20M
memory.limit_in_bytes cgroup to ext4 on USB stick.
ext4 (and gfs2 and xfs) turn out to allocate new pages for writing with
AOP_FLAG_NOFS: that seems a little worrying, and it's unclear to me why
the transaction needs to be started even before allocating pagecache
memory. But it may not be worth worrying about these days: if direct
reclaim avoids FS writeback, does __GFP_FS now mean anything?
Anyway, we insisted on the may_enter_fs test to avoid hangs with the loop
device; but since that also masks off __GFP_IO, we can test for __GFP_IO
directly, ignoring may_enter_fs and __GFP_FS.
But even so, the test still OOMs sometimes: when originally testing on
3.5-rc6, it OOMed about one time in five or ten; when testing just now on
3.5-rc6-mm1, it OOMed on the first iteration.
This residual problem comes from an accumulation of pages under ordinary
writeback, not marked PageReclaim, so rightly not causing the memcg check
to wait on their writeback: these too can prevent shrink_page_list() from
freeing any pages, so many times that memcg reclaim fails and OOMs.
Deal with these in the same way as direct reclaim now deals with dirty FS
pages: mark them PageReclaim. It is appropriate to rotate these to tail
of list when writepage completes, but more importantly, the PageReclaim
flag makes memcg reclaim wait on them if encountered again. Increment
NR_VMSCAN_IMMEDIATE? That's arguable: I chose not.
Setting PageReclaim here may occasionally race with end_page_writeback()
clearing it: lru_deactivate_fn() already faced the same race, and
correctly concluded that the window is small and the issue non-critical.
With these changes, the test runs indefinitely without OOMing on ext4,
ext3 and ext2: I'll move on to test with other filesystems later.
Trivia: invert conditions for a clearer block without an else, and goto
keep_locked to do the unlock_page.
Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Michal Hocko [Sat, 21 Jul 2012 00:54:33 +0000 (10:54 +1000)]
memcg: prevent OOM with too many dirty pages
The current implementation of dirty pages throttling is not memcg aware
which makes it easy to have memcg LRUs full of dirty pages. Without
throttling, these LRUs can be scanned faster than the rate of writeback,
leading to memcg OOM conditions when the hard limit is small.
This patch fixes the problem by throttling the allocating process
(possibly a writer) during the hard limit reclaim by waiting on
PageReclaim pages. We are waiting only for PageReclaim pages because
those are the pages that made one full round over LRU and that means that
the writeback is much slower than scanning.
The solution is far from being ideal - long term solution is memcg aware
dirty throttling - but it is meant to be a band aid until we have a real
fix. We are seeing this happening during nightly backups which are placed
into containers to prevent from eviction of the real working set.
The change affects only memcg reclaim and only when we encounter
PageReclaim pages which is a signal that the reclaim doesn't catch up on
with the writers so somebody should be throttled. This could be
potentially unfair because it could be somebody else from the group who
gets throttled on behalf of the writer but as writers need to allocate as
well and they allocate in higher rate the probability that only innocent
processes would be penalized is not that high.
I have tested this change by a simple dd copying /dev/zero to tmpfs or
ext3 running under small memcg (1G copy under 5M, 60M, 300M and 2G
containers) and dd got killed by OOM killer every time. With the patch I
could run the dd with the same size under 5M controller without any OOM.
The issue is more visible with slower devices for output.
* With the patch
================
* tmpfs size=2G
---------------
$ vim cgroup_cache_oom_test.sh
$ ./cgroup_cache_oom_test.sh 5M
using Limit 5M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 30.4049 s, 34.5 MB/s
$ ./cgroup_cache_oom_test.sh 60M
using Limit 60M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 31.4561 s, 33.3 MB/s
$ ./cgroup_cache_oom_test.sh 300M
using Limit 300M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 20.4618 s, 51.2 MB/s
$ ./cgroup_cache_oom_test.sh 2G
using Limit 2G for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 1.42172 s, 738 MB/s
* ext3
------
$ ./cgroup_cache_oom_test.sh 5M
using Limit 5M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 27.9547 s, 37.5 MB/s
$ ./cgroup_cache_oom_test.sh 60M
using Limit 60M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 30.3221 s, 34.6 MB/s
$ ./cgroup_cache_oom_test.sh 300M
using Limit 300M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 24.5764 s, 42.7 MB/s
$ ./cgroup_cache_oom_test.sh 2G
using Limit 2G for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 3.35828 s, 312 MB/s
* Without the patch
===================
* tmpfs size=2G
---------------
$ ./cgroup_cache_oom_test.sh 5M
using Limit 5M for group
./cgroup_cache_oom_test.sh: line 46: 4668 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count
$ ./cgroup_cache_oom_test.sh 60M
using Limit 60M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 25.4989 s, 41.1 MB/s
$ ./cgroup_cache_oom_test.sh 300M
using Limit 300M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 24.3928 s, 43.0 MB/s
$ ./cgroup_cache_oom_test.sh 2G
using Limit 2G for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 1.49797 s, 700 MB/s
* ext3
------
$ ./cgroup_cache_oom_test.sh 5M
using Limit 5M for group
./cgroup_cache_oom_test.sh: line 46: 4689 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count
$ ./cgroup_cache_oom_test.sh 60M
using Limit 60M for group
./cgroup_cache_oom_test.sh: line 46: 4692 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count
$ ./cgroup_cache_oom_test.sh 300M
using Limit 300M for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 20.248 s, 51.8 MB/s
$ ./cgroup_cache_oom_test.sh 2G
using Limit 2G for group
1000+0 records in
1000+0 records out 1048576000 bytes (1.0 GB) copied, 2.85201 s, 368 MB/s
[akpm@linux-foundation.org: tweak changelog, reordered the test to optimize for CONFIG_CGROUP_MEM_RES_CTLR=n]
[hughd@google.com: fix deadlock with loop driver] Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Reviewed-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm: mmu_notifier: fix freed page still mapped in secondary MMU
mmu_notifier_release() is called when the process is exiting. It will
delete all the mmu notifiers. But at this time the page belonging to the
process is still present in page tables and is present on the LRU list, so
this race will happen:
CPU 0 CPU 1
mmu_notifier_release: try_to_unmap:
hlist_del_init_rcu(&mn->hlist);
ptep_clear_flush_notify:
mmu nofifler not found
free page !!!!!!
/*
* At the point, the page has been
* freed, but it is still mapped in
* the secondary MMU.
*/
mn->ops->release(mn, mm);
Then the box is not stable and sometimes we can get this bug:
[ 738.075923] BUG: Bad page state in process migrate-perf pfn:03bec
[ 738.075931] page:ffffea00000efb00 count:0 mapcount:0 mapping: (null) index:0x8076
[ 738.075936] page flags: 0x20000000000014(referenced|dirty)
The same issue is present in mmu_notifier_unregister().
We can call ->release before deleting the notifier to ensure the page has
been unmapped from the secondary MMU before it is freed.
Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Sat, 21 Jul 2012 00:54:33 +0000 (10:54 +1000)]
mm: memcg: only check anon swapin page charges for swap cache
shmem knows for sure that the page is in swap cache when attempting to
charge a page, because the cache charge entry function has a check for it.
Only anon pages may be removed from swap cache already when trying to
charge their swapin.
Adjust the comment, though: '4969c11 mm: fix swapin race condition' added
a stable PageSwapCache check under the page lock in the do_swap_page()
before calling the memory controller, so it's unuse_pte()'s pte_same()
that may fail.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Sat, 21 Jul 2012 00:54:32 +0000 (10:54 +1000)]
mm: memcg: only check swap cache pages for repeated charging
Only anon and shmem pages in the swap cache are attempted to be charged
multiple times, from every swap pte fault or from shmem_unuse(). No other
pages require checking PageCgroupUsed().
Charging pages in the swap cache is also serialized by the page lock, and
since both the try_charge and commit_charge are called under the same page
lock section, the PageCgroupUsed() check might as well happen before the
counter charging, let alone reclaim.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Sat, 21 Jul 2012 00:54:32 +0000 (10:54 +1000)]
mm: memcg: split swapin charge function into private and public part
When shmem is charged upon swapin, it does not need to check twice whether
the memory controller is enabled.
Also, shmem pages do not have to be checked for everything that regular
anon pages have to be checked for, so let shmem use the internal version
directly and allow future patches to move around checks that are only
required when swapping in anon pages.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Charging cache pages may require swapin in the shmem case. Save the
forward declaration and just move the swapin functions above the cache
charging functions.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Sat, 21 Jul 2012 00:54:30 +0000 (10:54 +1000)]
mm: swapfile: clean up unuse_pte race handling
The conditional mem_cgroup_cancel_charge_swapin() is a leftover from when
the function would continue to reestablish the page even after
mem_cgroup_try_charge_swapin() failed. After 85d9fc8 "memcg: fix refcnt
handling at swapoff", the condition is always true when this code is
reached.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
swapfile: avoid dereferencing bd_disk during swap_entry_free for network storage
Commit b3a27d ("swap: Add swap slot free callback to
block_device_operations") dereferences p->bdev->bd_disk but this is a NULL
dereference if using swap-over-NFS. This patch checks SWP_BLKDEV on the
swap_info_struct before dereferencing.
With reference to this callback, Christoph Hellwig stated "Please just
remove the callback entirely. It has no user outside the staging tree and
was added clearly against the rules for that staging tree". This would
also be my preference but there was not an obvious way of keeping zram in
staging/ happy.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David S. Miller <davem@davemloft.net> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Paris <eparis@redhat.com> Cc: James Morris <jmorris@namei.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / karo-tx-linux.git / log