mm: page allocator: adjust the per-cpu counter threshold when memory is low

Upstream commit 88f5acf88ae6a9778f6d25d0d5d7ec2d57764a97

Commit aa45484 ("calculate a better estimate of NR_FREE_PAGES when memory
is low") noted that watermarks were based on the vmstat NR_FREE_PAGES.  To
avoid synchronization overhead, these counters are maintained on a per-cpu
basis and drained both periodically and when a threshold is above a
threshold.  On large CPU systems, the difference between the estimate and
real value of NR_FREE_PAGES can be very high.  The system can get into a
case where pages are allocated far below the min watermark potentially
causing livelock issues.  The commit solved the problem by taking a better
reading of NR_FREE_PAGES when memory was low.

Unfortately, as reported by Shaohua Li this accurate reading can consume a
large amount of CPU time on systems with many sockets due to cache line
bouncing.  This patch takes a different approach.  For large machines
where counter drift might be unsafe and while kswapd is awake, the per-cpu
thresholds for the target pgdat are reduced to limit the level of drift to
what should be a safe level.  This incurs a performance penalty in heavy
memory pressure by a factor that depends on the workload and the machine
but the machine should function correctly without accidentally exhausting
all memory on a node.  There is an additional cost when kswapd wakes and
sleeps but the event is not expected to be frequent - in Shaohua's test
case, there was one recorded sleep and wake event at least.

To ensure that kswapd wakes up, a safe version of zone_watermark_ok() is
introduced that takes a more accurate reading of NR_FREE_PAGES when called
from wakeup_kswapd, when deciding whether it is really safe to go back to
sleep in sleeping_prematurely() and when deciding if a zone is really
balanced or not in balance_pgdat().  We are still using an expensive
function but limiting how often it is called.

When the test case is reproduced, the time spent in the watermark
functions is reduced.  The following report is on the percentage of time
spent cumulatively spent in the functions zone_nr_free_pages(),
zone_watermark_ok(), __zone_watermark_ok(), zone_watermark_ok_safe(),
zone_page_state_snapshot(), zone_page_state().

vanilla                      11.6615%
disable-threshold            0.2584%

David said:

: We had to pull aa454840 "mm: page allocator: calculate a better estimate
: of NR_FREE_PAGES when memory is low and kswapd is awake" from 2.6.36
: internally because tests showed that it would cause the machine to stall
: as the result of heavy kswapd activity.  I merged it back with this fix as
: it is pending in the -mm tree and it solves the issue we were seeing, so I
: definitely think this should be pushed to -stable (and I would seriously
: consider it for 2.6.37 inclusion even at this late date).

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reported-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Tested-by: Nicolas Bareil <nico@chdir.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: <stable@kernel.org>		[2.6.37.1, 2.6.36.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

backported from 88f5acf88ae6a9778f6d25d0d5d7ec2d57764a97
BugLink: http://bugs.launchpad.net/bugs/719446
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
qla2xxx: Make the FC port capability mutual exclusive.

[ upstream commit b0cd579cde8ee0c7ed52239531ba09bcbc5b54c2 ]

In case of both target and initiator capabilities reported by fc port,
the fc port port capability is made mutualy exclusive with priority given
for target capabilities.

Signed-off-by: Giridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Acked-by: Madhuranath Iyengar <Madhu.Iyengar@qlogic.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
staging: usbip: bugfixes related to kthread conversion

commit d2dd0b07c3e725d386d20294ec906f7ddef207fa upstream.

When doing a usb port reset do a queued reset instead to prevent a
deadlock: the reset will cause the driver to unbind, causing the
usb_driver_lock_for_reset to stall.

Signed-off-by: Arjan Mels <arjan.mels@gmx.net>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Cc: Max Vozeler <max@vozeler.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: usbip: bugfix add number of packets for isochronous frames

commit 1325f85fa49f57df034869de430f7c302ae23109 upstream.

The number_of_packets was not transmitted for RET_SUBMIT packets. The
linux client used the stored number_of_packet from the submitted
request. The windows userland client does not do this however and needs
to know the number_of_packets to determine the size of the transmission.

Signed-off-by: Arjan Mels <arjan.mels@gmx.net>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Cc: Max Vozeler <max@vozeler.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: usbip: bugfix for isochronous packets and optimization

commit 28276a28d8b3cd19f4449991faad4945fe557656 upstream.

For isochronous packets the actual_length is the sum of the actual
length of each of the packets, however between the packets might be
padding, so it is not sufficient to just send the first actual_length
bytes of the buffer. To fix this and simultanesouly optimize the
bandwidth the content of the isochronous packets are send without the
padding, the padding is restored on the receiving end.

Signed-off-by: Arjan Mels <arjan.mels@gmx.net>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Takahiro Hirofuchi <hirofuchi@users.sourceforge.net>
Cc: Max Vozeler <max@vozeler.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
staging: hv: Fix GARP not sent after Quick Migration

commit c996edcf1c451b81740abbcca5257ed7e353fcc6 upstream.

After Quick Migration, the network is not immediately operational in the
current context when receiving RNDIS_STATUS_MEDIA_CONNECT event. So, I added
another netif_notify_peers() into a scheduled work, otherwise GARP packet will
not be sent after quick migration, and cause network disconnection.

Thanks to Mike Surcouf <mike@surcouf.co.uk> for reporting the bug and
testing the patch.

Reported-by: Mike Surcouf <mike@surcouf.co.uk>
Tested-by: Mike Surcouf <mike@surcouf.co.uk>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
staging: hv: use sync_bitops when interacting with the hypervisor

commit 22356585712d1ff08fbfed152edd8b386873b238 upstream.

Locking is required when tweaking bits located in a shared page, use the
sync_ version of bitops. Without this change vmbus_on_event() will miss
events and as a result, vmbus_isr() will not schedule the receive tasklet.

[Backported to 2.6.32 stable kernel by Haiyang Zhang <haiyangz@microsoft.com>]

Signed-off-by: Olaf Hering <olaf@aepfle.de>
Acked-by: Haiyang Zhang <haiyangz@microsoft.com>
Acked-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
xfs: prevent leaking uninitialized stack memory in FSGEOMETRY_V1

commit c4d0c3b097f7584772316ee4d64a09fe0e4ddfca upstream.

The FSGEOMETRY_V1 ioctl (and its compat equivalent) calls out to
xfs_fs_geometry() with a version number of 3.  This code path does not
fill in the logsunit member of the passed xfs_fsop_geom_t, leading to
the leaking of four bytes of uninitialized stack data to potentially
unprivileged callers.

v2 switches to memset() to avoid future issues if structure members
change, on suggestion of Dave Chinner.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Eugene Teo <eugeneteo@kernel.org>
Signed-off-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
irda: prevent heap corruption on invalid nickname

commit d50e7e3604778bfc2dc40f440e0742dbae399d54 upstream.

Invalid nicknames containing only spaces will result in an underflow in
a memcpy size calculation, subsequently destroying the heap and
panicking.

v2 also catches the case where the provided nickname is longer than the
buffer size, which can result in controllable heap corruption.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
irda: validate peer name and attribute lengths

commit d370af0ef7951188daeb15bae75db7ba57c67846 upstream.

Length fields provided by a peer for names and attributes may be longer
than the destination array sizes.  Validate lengths to prevent stack
buffer overflows.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
nilfs2: fix data loss in mmap page write for hole blocks

commit 34094537943113467faee98fe67c8a3d3f9a0a8b upstream.

From the result of a function test of mmap, mmap write to shared pages
turned out to be broken for hole blocks.  It doesn't write out filled
blocks and the data will be lost after umount.  This is due to a bug
that the target file is not queued for log writer when filling hole
blocks.

Also, nilfs_page_mkwrite function exits normal code path even after
successfully filled hole blocks due to a change of block_page_mkwrite
function; just after nilfs was merged into the mainline,
block_page_mkwrite() started to return VM_FAULT_LOCKED instead of zero
by the patch "mm: close page_mkwrite races" (commit:
b827e496c893de0c).  The current nilfs_page_mkwrite() is not handling
this value properly.

This corrects nilfs_page_mkwrite() and will resolve the data loss
problem in mmap write.

[This should be applied to every kernel since 2.6.30 but a fix is
 needed for 2.6.37 and prior kernels]

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
ASoC: Explicitly say registerless widgets have no register

commit 0ca03cd7d0fa3bfbd56958136a10f19733c4ce12 upstream.

This stops code that handles widgets generically from attempting to access
registers for these widgets.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
ALSA: ens1371: fix Creative Ectiva support

commit 6ebb8a4a43e34f999ab36f27f972f3cd751cda4f upstream.

To make the EV1938 chip work, add a magic bit and an extra delay.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Tino Schmidt <mailtinoshomepage@gmx.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
ROSE: prevent heap corruption with bad facilities

commit be20250c13f88375345ad99950190685eda51eb8 upstream.

When parsing the FAC_NATIONAL_DIGIS facilities field, it's possible for
a remote host to provide more digipeaters than expected, resulting in
heap corruption.  Check against ROSE_MAX_DIGIS to prevent overflows, and
abort facilities parsing on failure.

Additionally, when parsing the FAC_CCITT_DEST_NSAP and
FAC_CCITT_SRC_NSAP facilities fields, a remote host can provide a length
of less than 10, resulting in an underflow in a memcpy size, causing a
kernel panic due to massive heap corruption.  A length of greater than
20 results in a stack overflow of the callsign array.  Abort facilities
parsing on these invalid length values.

Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Btrfs: Fix uninitialized root flags for subvolumes

commit 08fe4db170b4193603d9d31f40ebaf652d07ac9c upstream.

root_item->flags and root_item->byte_limit are not initialized when
a subvolume is created. This bug is not revealed until we added
readonly snapshot support - now you mount a btrfs filesystem and you
may find the subvolumes in it are readonly.

To work around this problem, we steal a bit from root_item->inode_item->flags,
and use it to indicate if those fields have been properly initialized.
When we read a tree root from disk, we check if the bit is set, and if
not we'll set the flag and initialize the two fields of the root item.

Reported-by: Andreas Philipp <philipp.andreas@gmail.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Andreas Philipp <philipp.andreas@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
x86, mtrr, pat: Fix one cpu getting out of sync during resume

commit 84ac7cdbdd0f04df6b96153f7a79127fd6e45467 upstream.

On laptops with core i5/i7, there were reports that after resume
graphics workloads were performing poorly on a specific AP, while
the other cpu's were ok. This was observed on a 32bit kernel
specifically.

Debug showed that the PAT init was not happening on that AP
during resume and hence it contributing to the poor workload
performance on that cpu.

On this system, resume flow looked like this:

1. BP starts the resume sequence and we reinit BP's MTRR's/PAT
   early on using mtrr_bp_restore()

2. Resume sequence brings all AP's online

3. Resume sequence now kicks off the MTRR reinit on all the AP's.

4. For some reason, between point 2 and 3, we moved from BP
   to one of the AP's. My guess is that printk() during resume
   sequence is contributing to this. We don't see similar
   behavior with the 64bit kernel but there is no guarantee that
   at this point the remaining resume sequence (after AP's bringup)
   has to happen on BP.

5. set_mtrr() was assuming that we are still on BP and skipped the
   MTRR/PAT init on that cpu (because of 1 above)

6. But we were on an AP and this led to not reprogramming PAT
   on this cpu leading to bad performance.

Fix this by doing unconditional mtrr_if->set_all() in set_mtrr()
during MTRR/PAT init. This might be unnecessary if we are still
running on BP. But it is of no harm and will guarantee that after
resume, all the cpu's will be in sync with respect to the
MTRR/PAT registers.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
LKML-Reference: <1301438292-28370-1-git-send-email-eric@anholt.net>
Signed-off-by: Eric Anholt <eric@anholt.net>
Tested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
UBIFS: fix oops on error path in read_pnode

commit 54acbaaa523ca0bd284a18f67ad213c379679e86 upstream.

Thanks to coverity which spotted that UBIFS will oops if 'kmalloc()'
in 'read_pnode()' fails and we dereference a NULL 'pnode' pointer
when we 'goto out'.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
UBIFS: do not read flash unnecessarily

commit 8b229c76765816796eec7ccd428f03bd8de8b525 upstream.

This fix makes the 'dbg_check_old_index()' function return
immediately if debugging is disabled, instead of executing
incorrect 'goto out' which causes UBIFS to:

1. Allocate memory
2. Read the flash

On every commit. OK, we do not commit that often, but it is
still silly to do unneeded I/O anyway.

Credits to coverity for spotting this silly issue.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
UBIFS: fix debugging failure in dbg_check_space_info

commit 7da6443aca9be29c6948dcbd636ad50154d0bc0c upstream.

This patch fixes a debugging failure with which looks like this:
UBIFS error (pid 32313): dbg_check_space_info: free space changed from 6019344 to 6022654

The reason for this failure is described in the comment this patch adds
to the code. But in short - 'c->freeable_cnt' may be different before
and after re-mounting, and this is normal. So the debugging code should
make sure that free space calculations do not depend on 'c->freeable_cnt'.

A similar issue has been reported here:
http://lists.infradead.org/pipermail/linux-mtd/2011-April/034647.html

This patch should fix it.

For the -stable guys: this patch is only relevant for kernels 2.6.30
onwards.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
quota: Don't write quota info in dquot_commit()

commit b03f24567ce7caf2420b8be4c6eb74c191d59a91 upstream.

There's no reason to write quota info in dquot_commit(). The writing is a
relict from the old days when we didn't have dquot_acquire() and
dquot_release() and thus dquot_commit() could have created / removed quota
structures from the file. These days dquot_commit() only updates usage counters
/ limits in quota structure and thus there's no need to write quota info.

This also fixes an issue with journaling filesystem which didn't reserve
enough space in the transaction for write of quota info (it could have been
dirty at the time of dquot_commit() because of a race with other operation
changing it).

Reported-and-tested-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Andi Kleen <ak@linux.intel.com>