Some brilliant hardware implementations wake multiple cores when the
broadcast timer fires. This leads to the following interesting
problem:
CPU0 CPU1
wakeup from idle wakeup from idle
leave broadcast mode leave broadcast mode
restart per cpu timer restart per cpu timer
go back to idle
handle broadcast
(empty mask)
enter broadcast mode
programm broadcast device
enter broadcast mode
programm broadcast device
So what happens is that due to the forced reprogramming of the cpu
local timer, we need to set a event in the future. Now if we manage to
go back to idle before the timer fires, we switch off the timer and
arm the broadcast device with an already expired time (covered by
forced mode). So in the worst case we repeat the above ping pong
forever.
Unfortunately we have no information about what caused the wakeup, but
we can check current time against the expiry time of the local cpu. If
the local event is already in the past, we know that the broadcast
timer is about to fire and send an IPI. So we mark ourself as an IPI
target even if we left broadcast mode and avoid the reprogramming of
the local cpu timer.
This still leaves the possibility that a CPU which is not handling the
broadcast interrupt is going to reach idle again before the IPI
arrives. This can't be solved in the core code and will be handled in
follow up patches.
Reported-by: Jason Liu <liu.h.jason@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: http://lkml.kernel.org/r/20130306111537.492045206@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
If the local cpu timer stops in deep idle, we arm the broadcast device
and get woken by an IPI. Now when we return from deep idle we reenable
the local cpu timer unconditionally before handling the IPI. But
that's a pointless exercise: the timer is already expired and the IPI
is on the way. And it's an expensive exercise as we use the forced
reprogramming mode so that we do not lose a timer event. This forced
reprogramming will loop at least once in the retry.
To avoid this reprogramming, we mark the cpu in a pending bit mask
before we send the IPI. Now when the IPI target cpu wakes up, it will
see the pending bit set and skip the reprogramming. The reprogramming
of the cpu local timer will happen in the IPI handler which runs the
cpu local timer interrupt function.
Reported-by: Jason Liu <liu.h.jason@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Arjan van de Veen <arjan@infradead.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Link: http://lkml.kernel.org/r/20130306111537.431082074@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Pull namespace bugfixes from Eric Biederman:
"This is three simple fixes against 3.9-rc1. I have tested each of
these fixes and verified they work correctly.
The userns oops in key_change_session_keyring and the BUG_ON triggered
by proc_ns_follow_link were found by Dave Jones.
I am including the enhancement for mount to only trigger requests of
filesystem modules here instead of delaying this for the 3.10 merge
window because it is both trivial and the kind of change that tends to
bit-rot if left untouched for two months."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Use nd_jump_link in proc_ns_follow_link
fs: Limit sys_mount to only request filesystem modules (Part 2).
fs: Limit sys_mount to only request filesystem modules.
userns: Stop oopsing in key_change_session_keyring
There is a more complete atmel patch-series out by Nick Dyer that fixes
this and other things, but in the meantime this is the minimal thing to
get the touchscreen going on (at least my) Pixel Chromebook.
Not that I want my dirty fingers near that beautiful screen, but it
seems that a non-initialized touchscreen will also end up being a
constant wakeup source, so you have to disable it to go to sleep. And
it's easier to just fix the initialization sequence.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Update proc_ns_follow_link to use nd_jump_link instead of just
manually updating nd.path.dentry.
This fixes the BUG_ON(nd->inode != parent->d_inode) reported by Dave
Jones and reproduced trivially with mkdir /proc/self/ns/uts/a.
Sigh it looks like the VFS change to require use of nd_jump_link
happend while proc_ns_follow_link was baking and since the common case
of proc_ns_follow_link continued to work without problems the need for
making this change was overlooked.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull btrfs fixes from Chris Mason:
"These are scattered fixes and one performance improvement. The
biggest functional change is in how we throttle metadata changes. The
new code bumps our average file creation rate up by ~13% in fs_mark,
and lowers CPU usage.
Stefan bisected out a regression in our allocation code that made
balance loop on extents larger than 256MB."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: improve the delayed inode throttling
Btrfs: fix a mismerge in btrfs_balance()
Btrfs: enforce min_bytes parameter during extent allocation
Btrfs: allow running defrag in parallel to administrative tasks
Btrfs: avoid deadlock on transaction waiting list
Btrfs: do not BUG_ON on aborted situation
Btrfs: do not BUG_ON in prepare_to_reloc
Btrfs: free all recorded tree blocks on error
Btrfs: build up error handling for merge_reloc_roots
Btrfs: check for NULL pointer in updating reloc roots
Btrfs: fix unclosed transaction handler when the async transaction commitment fails
Btrfs: fix wrong handle at error path of create_snapshot() when the commit fails
Btrfs: use set_nlink if our i_nlink is 0
Add basic platform data to get the current upstream driver working
with the 224s touchpad and 1664s touchscreen.
We will be using NULL config so we will use the settings from the
devices' NVRAMs.
Signed-off-by: Benson Leung <bleung@chromium.org>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This same driver can be used by atmel based touchscreens and touchpads
(buttonpads). Platform data may specify a device is a touchpad
using the is_tp flag.
This will cause the driver to perform some touchpad specific
initializations, such as:
* register input device name "Atmel maXTouch Touchpad" instead of
Touchscreen.
* register BTN_LEFT & BTN_TOOL_* event types.
* register axis resolution (as a fixed constant, for now)
* register BUTTONPAD property
* process GPIO buttons using reportid T19
Input event GPIO mapping is done by the platform data key_map array.
key_map[x] should contain the KEY or BTN code to send when processing
GPIOx from T19. To specify a GPIO as not an input source, populate
with KEY_RESERVED, or 0.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull CIFS fixes from Steve French:
"A small set of cifs fixes which includes one for a recent regression
in the write path (pointed out by Anton), some fixes for rename
problems and as promised for 3.9 removing the obsolete sockopt mount
option (and the accompanying deprecation warning)."
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
CIFS: Fix missing of oplock_read value in smb30_values structure
cifs: don't try to unlock pagecache page after releasing it
cifs: remove the sockopt= mount option
cifs: Check server capability before attempting silly rename
cifs: Fix bug when checking error condition in cifs_rename_pending_delete()
Merge misc fixes from Andrew Morton.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
alpha: boot: fix build breakage introduced by system.h disintegration
memcg: initialize kmem-cache destroying work earlier
Randy has moved
ksm: fix m68k build: only NUMA needs pfn_to_nid
dmi_scan: fix missing check for _DMI_ signature in smbios_present()
Revert parts of "hlist: drop the node parameter from iterators"
idr: remove WARN_ON_ONCE() on negative IDs
mm/mempolicy.c: fix sp_node_init() argument ordering
mm/mempolicy.c: fix wrong sp_node insertion
ipc: don't allocate a copy larger than max
ipc: fix potential oops when src msg > 4k w/ MSG_COPY
A CONFIG_DISCONTIGMEM=y m68k config gave
mm/ksm.c: In function `get_kpfn_nid':
mm/ksm.c:492: error: implicit declaration of function `pfn_to_nid'
linux/mmzone.h declares it for CONFIG_SPARSEMEM and CONFIG_FLATMEM, but
expects the arch's asm/mmzone.h to declare it for CONFIG_DISCONTIGMEM
(see arch/mips/include/asm/mmzone.h for example).
Or perhaps it is only expected when CONFIG_NUMA=y: too much of a maze,
and m68k got away without it so far, so fix the build in mm/ksm.c.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Petr Holasek <pholasek@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 9f9c9cbb60 ("drivers/firmware/dmi_scan.c: fetch dmi version
from SMBIOS if it exists") hoisted the check for "_DMI_" into
dmi_scan_machine(), which means that we don't bother to check for
"_DMI_" at offset 16 in an SMBIOS entry. smbios_present() may also call
dmi_present() for an address where we found "_SM_", if it failed further
validation.
Check for "_DMI_" in smbios_present() before calling dmi_present().
[akpm@linux-foundation.org: fix build]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reported-by: Tim McGrath <tmhikaru@gmail.com>
Tested-by: Tim Mcgrath <tmhikaru@gmail.com>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
idr_find(), idr_remove() and idr_replace() used to silently ignore the
sign bit and perform lookup with the rest of the bits. The weird behavior
has been changed such that negative IDs are treated as invalid. As the
behavior change was subtle, WARN_ON_ONCE() was added in the hope of
determining who's calling idr functions with negative IDs so that they can
be examined for problems.
Up until now, all two reported cases are ID number coming directly from
userland and getting fed into idr_find() and the warnings seem to cause
more problems than being helpful. Drop the WARN_ON_ONCE()s.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: <markus@trippelsdorf.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull tile architecture fixes from Chris Metcalf:
"This fixes the bug that Al Viro spotted with the compat llseek code.
I also fixed the compat syscall definitions to use the new syscall
define macros to properly sign-extend their arguments."
* 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
tile: properly use COMPAT_SYSCALL_DEFINEx
tile: work around bug in the generic sys_llseek
Pull metag bugfixes from James Hogan:
"A couple of fairly minor arch/metag integration fixes from v3.9-rc1:
- remove SET_PERSONALITY(): use default definition like other arches
now do.
- inhibit NUMA balancing: like SH, NUMA is used for memories with
different latencies. ARCH_WANT_VARIABLE_LOCALITY has been added
for this purpose."
* tag 'metag-for-v3.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag:
metag: Inhibit NUMA balancing.
metag: remove SET_PERSONALITY()
Thomas Gleixner
Linus Torvalds
Eric W. Biederman
Benson Leung
Daniel Kurtz
Will Deacon
Konstantin Khlebnikov
Randy Dunlap
Hugh Dickins
Ben Hutchings
Arnd Bergmann
Tejun Heo
KOSAKI Motohiro
Hillf Danton
Peter Hurley