Now that the return from alloc_percpu is compatible with the address
of per-cpu vars, it makes sense to hand around the address of per-cpu
variables. To make this sane, we remove the per_cpu__ prefix we used
created to stop people accidentally using these vars directly.
Now we have sparse, we can use that (next patch).
tj: * Updated to convert stuff which were missed by or added after the
original patch.
* Kill per_cpu_var() macro.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Make the following changes to remove some sparse warnings.
* Make DEFINE_PER_CPU_SECTION() declare __pcpu_unique_* before
defining it.
* Annotate pcpu_extend_area_map() that it is entered with pcpu_lock
held, releases it and then reacquires it.
* Make percpu related macros use unique nested variable names.
* While at it, add pcpu prefix to __size_call[_return]() macros as
to-be-implemented sparse annotations will add percpu specific stuff
to these macros.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
alloc_percpu() couldn't handle array types like "int [100]" due to the
way return type was casted. Fix it by using typeof() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Using per cpu atomics for the vm statistics reduces their overhead.
And in the case of x86 we are guaranteed that they will never race even
in the lax form used for vm statistics.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
SNMP statistic macros can be signficantly simplified.
This will also reduce code size if the arch supports these operations
in hardware.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch introduces two things: First this_cpu_ptr and then per cpu
atomic operations.
this_cpu_ptr
------------
A common operation when dealing with cpu data is to get the instance of the
cpu data associated with the currently executing processor. This can be
optimized by
this_cpu_ptr(xx) = per_cpu_ptr(xx, smp_processor_id).
The problem with per_cpu_ptr(x, smp_processor_id) is that it requires
an array lookup to find the offset for the cpu. Processors typically
have the offset for the current cpu area in some kind of (arch dependent)
efficiently accessible register or memory location.
We can use that instead of doing the array lookup to speed up the
determination of the address of the percpu variable. This is particularly
significant because these lookups occur in performance critical paths
of the core kernel. this_cpu_ptr() can avoid memory accesses and
this_cpu_ptr comes in two flavors. The preemption context matters since we
are referring the the currently executing processor. In many cases we must
insure that the processor does not change while a code segment is executed.
__this_cpu_ptr -> Do not check for preemption context
this_cpu_ptr -> Check preemption context
The parameter to these operations is a per cpu pointer. This can be the
address of a statically defined per cpu variable (&per_cpu_var(xxx)) or
the address of a per cpu variable allocated with the per cpu allocator.
per cpu atomic operations: this_cpu_*(var, val)
-----------------------------------------------
this_cpu_* operations (like this_cpu_add(struct->y, value) operate on
abitrary scalars that are members of structures allocated with the new
per cpu allocator. They can also operate on static per_cpu variables
if they are passed to per_cpu_var() (See patch to use this_cpu_*
operations for vm statistics).
These operations are guaranteed to be atomic vs preemption when modifying
the scalar. The calculation of the per cpu offset is also guaranteed to
be atomic at the same time. This means that a this_cpu_* operation can be
safely used to modify a per cpu variable in a context where interrupts are
enabled and preemption is allowed. Many architectures can perform such
a per cpu atomic operation with a single instruction.
Note that the atomicity here is different from regular atomic operations.
Atomicity is only guaranteed for data accessed from the currently executing
processor. Modifications from other processors are still possible. There
must be other guarantees that the per cpu data is not modified from another
processor when using these instruction. The per cpu atomicity is created
by the fact that the processor either executes and instruction or not.
Embedded in the instruction is the relocation of the per cpu address to
the are reserved for the current processor and the RMW action. Therefore
interrupts or preemption cannot occur in the mids of this processing.
Generic fallback functions are used if an arch does not define optimized
this_cpu operations. The functions come also come in the two flavors used
for this_cpu_ptr().
The firstparameter is a scalar that is a member of a structure allocated
through allocpercpu or a per cpu variable (use per_cpu_var(xxx)). The
operations are similar to what percpu_add() and friends do.
this_cpu_read(scalar)
this_cpu_write(scalar, value)
this_cpu_add(scale, value)
this_cpu_sub(scalar, value)
this_cpu_inc(scalar)
this_cpu_dec(scalar)
this_cpu_and(scalar, value)
this_cpu_or(scalar, value)
this_cpu_xor(scalar, value)
Arch code can override the generic functions and provide optimized atomic
per cpu operations. These atomic operations must provide both the relocation
(x86 does it through a segment override) and the operation on the data in a
single instruction. Otherwise preempt needs to be disabled and there is no
gain from providing arch implementations.
A third variant is provided prefixed by irqsafe_. These variants are safe
against hardware interrupts on the *same* processor (all per cpu atomic
primitives are *always* *only* providing safety for code running on the
*same* processor!). The increment needs to be implemented by the hardware
in such a way that it is a single RMW instruction that is either processed
before or after an interrupt.
cc: David Howells <dhowells@redhat.com>
cc: Ingo Molnar <mingo@elte.hu>
cc: Rusty Russell <rusty@rustcorp.com.au>
cc: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch clean up/fixes for memcg's uncharge soft limit path.
Problems:
Now, res_counter_charge()/uncharge() handles softlimit information at
charge/uncharge and softlimit-check is done when event counter per memcg
goes over limit. Now, event counter per memcg is updated only when
memory usage is over soft limit. Here, considering hierarchical memcg
management, ancesotors should be taken care of.
Now, ancerstors(hierarchy) are handled in charge() but not in uncharge().
This is not good.
Prolems:
1. memcg's event counter incremented only when softlimit hits. That's bad.
It makes event counter hard to be reused for other purpose.
2. At uncharge, only the lowest level rescounter is handled. This is bug.
Because ancesotor's event counter is not incremented, children should
take care of them.
3. res_counter_uncharge()'s 3rd argument is NULL in most case.
ops under res_counter->lock should be small. No "if" sentense is better.
Fixes:
* Removed soft_limit_xx poitner and checks in charge and uncharge.
Do-check-only-when-necessary scheme works enough well without them.
* make event-counter of memcg incremented at every charge/uncharge.
(per-cpu area will be accessed soon anyway)
* All ancestors are checked at soft-limit-check. This is necessary because
ancesotor's event counter may never be modified. Then, they should be
checked at the same time.
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The asm-generic/gpio.h header uses the might_sleep() macro but doesn't
include the header for it, so any source code that might include
linux/gpio.h before linux/kernel.h can easily lead to a build failure.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This provides safety against negative optlen at the type
level instead of depending upon (sometimes non-trivial)
checks against this sprinkled all over the the place, in
each and every implementation.
Based upon work done by Arjan van de Ven and feedback
from Linus Torvalds.
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: Fix time encoding with extra epoch bits
ext4: Add a stub for mpage_da_data in the trace header
jbd2: Use tracepoints for history file
ext4: Use tracepoints for mb_history trace file
ext4, jbd2: Drop unneeded printks at mount and unmount time
ext4: Handle nested ext4_journal_start/stop calls without a journal
ext4: Make sure ext4_dirty_inode() updates the inode in no journal mode
ext4: Avoid updating the inode table bh twice in no journal mode
ext4: EXT4_IOC_MOVE_EXT: Check for different original and donor inodes first
ext4: async direct IO for holes and fallocate support
ext4: Use end_io callback to avoid direct I/O fallback to buffered I/O
ext4: Split uninitialized extents for direct I/O
ext4: release reserved quota when block reservation for delalloc retry
ext4: Adjust ext4_da_writepages() to write out larger contiguous chunks
ext4: Fix hueristic which avoids group preallocation for closed files
ext4: Use ext4_msg() for ext4_da_writepage() errors
ext4: Update documentation about quota mount options
* 'pm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6:
PM / yenta: Fix cardbus suspend/resume regression
PM / PCMCIA: Drop second argument of pcmcia_socket_dev_suspend()
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (33 commits)
sony-laptop: re-read the rfkill state when resuming from suspend
sony-laptop: check for rfkill hard block at load time
wext: add back wireless/ dir in sysfs for cfg80211 interfaces
wext: Add bound checks for copy_from_user
mac80211: improve/fix mlme messages
cfg80211: always get BSS
iwlwifi: fix 3945 ucode info retrieval after failure
iwlwifi: fix memory leak in command queue handling
iwlwifi: fix debugfs buffer handling
cfg80211: don't set privacy w/o key
cfg80211: wext: don't display BSSID unless associated
net: Add explicit bound checks in net/socket.c
bridge: Fix double-free in br_add_if.
isdn: fix netjet/isdnhdlc build errors
atm: dereference of he_dev->rbps_virt in he_init_group()
ax25: Add missing dev_put in ax25_setsockopt
Revert "sit: stateless autoconf for isatap"
net: fix double skb free in dcbnl
net: fix nlmsg len size for skb when error bit is set.
net: fix vlan_get_size to include vlan_flags size
...
* 'drm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (25 commits)
drm/radeon/kms: Convert R520 to new init path and associated cleanup
drm/radeon/kms: Convert RV515 to new init path and associated cleanup
drm: fix radeon DRM warnings when !CONFIG_DEBUG_FS
drm: fix drm_fb_helper warning when !CONFIG_MAGIC_SYSRQ
drm/r600: fix memory leak introduced with 64k malloc avoidance fix.
drm/kms: make fb helper work for all drivers.
drm/radeon/r600: fix offset handling in CS parser
drm/radeon/kms/r600: fix forcing pci mode on agp cards
drm/radeon/kms: fix for the extra pages copying.
drm/radeon/kms/r600: add support for vline relocs
drm/radeon/kms: fix some bugs in vline reloc
drm/radeon/kms/r600: clamp vram to aperture size
drm/kms: protect against fb helper not being created.
drm/r600: get values from the passed in IB not the copy.
drm: create gitignore file for radeon
drm/radeon/kms: remove unneeded master create/destroy functions.
drm/kms: start adding command line interface using fb.
fb: change rules for global rules match.
drm/radeon/kms: don't require up to 64k allocations. (v2)
drm/radeon/kms: enable dac load detection by default.
...
Trivial conflicts in drivers/gpu/drm/radeon/radeon_asic.h due to adding
'->vga_set_state' function pointers.
The tracepoint ext4_da_write_pages has a struct mpage_da_data*
parameter, but that struct is only defined in fs/ext4/ext4.h. This
patch adds a forward declaration for that struct, so this tracepoint
header can still be used by tools like SystemTap.
This is a continuation of the fix in commit 3661d286.
http://sourceware.org/bugzilla/show_bug.cgi?id=10703
Signed-off-by: Josh Stone <jistone@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The /proc/fs/jbd2/<dev>/history was maintained manually; by using
tracepoints, we can get all of the existing functionality of the /proc
file plus extra capabilities thanks to the ftrace infrastructure. We
save memory as a bonus.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The /proc/fs/ext4/<dev>/mb_history was maintained manually, and had a
number of problems: it required a largish amount of memory to be
allocated for each ext4 filesystem, and the s_mb_history_lock
introduced a CPU contention problem.
By ripping out the mb_history code and replacing it with ftrace
tracepoints, and we get more functionality: timestamps, event
filtering, the ability to correlate mballoc history with other ext4
tracepoints, etc.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
pcmcia_socket_dev_suspend() doesn't use its second argument, so it
may be dropped safely.
This change is necessary for the subsequent yenta suspend/resume fix.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@kernel.org
The move away from having drivers assign wireless handlers,
in favour of making cfg80211 assign them, broke the sysfs
registration (the wireless/ dir went missing) because the
handlers are now assigned only after registration, which is
too late.
Fix this by special-casing cfg80211-based devices, all
of which are required to have an ieee80211_ptr, in the
sysfs code, and also using get_wireless_stats() to have
the same values reported as in procfs.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Tested-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Work around problems in the writeback code to force out writebacks in
larger chunks than just 4mb, which is just too small. This also works
around limitations in the ext4 block allocator, which can't allocate
more than 2048 blocks at a time. So we need to defeat the round-robin
characteristics of the writeback code and try to write out as many
blocks in one inode before allowing the writeback code to move on to
another inode. We add a a new per-filesystem tunable,
max_writeback_mb_bump, which caps this to a default of 128mb per
inode.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
