Allow to dynamically switch between tick and virtual based
cputime accounting. This way we can provide a kind of "on-demand"
virtual based cputime accounting. In this mode, the kernel relies
on the context tracking subsystem to dynamically probe on kernel
boundaries.
This is in preparation for being able to stop the timer tick in
more places than just the idle state. Doing so will depend on
CONFIG_VIRT_CPU_ACCOUNTING_GEN which makes it possible to account
the cputime without the tick by hooking on kernel/user boundaries.
Depending whether the tick is stopped or not, we can switch between
tick and vtime based accounting anytime in order to minimize the
overhead associated to user hooks.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
If we want to stop the tick further idle, we need to be
able to account the cputime without using the tick.
Virtual based cputime accounting solves that problem by
hooking into kernel/user boundaries.
However implementing CONFIG_VIRT_CPU_ACCOUNTING require
low level hooks and involves more overhead. But we already
have a generic context tracking subsystem that is required
for RCU needs by archs which plan to shut down the tick
outside idle.
This patch implements a generic virtual based cputime
accounting that relies on these generic kernel/user hooks.
There are some upsides of doing this:
- This requires no arch code to implement CONFIG_VIRT_CPU_ACCOUNTING
if context tracking is already built (already necessary for RCU in full
tickless mode).
- We can rely on the generic context tracking subsystem to dynamically
(de)activate the hooks, so that we can switch anytime between virtual
and tick based accounting. This way we don't have the overhead
of the virtual accounting when the tick is running periodically.
And one downside:
- There is probably more overhead than a native virtual based cputime
accounting. But this relies on hooks that are already set anyway.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
If the architecture doesn't provide an implementation of
nsecs_to_cputime(), the cputime accounting core uses a
default one that converts the nanoseconds to jiffies. However
this only makes sense if we use the jiffies based cputime.
For now it doesn't matter much because this API is only
called on code that uses jiffies based cputime accounting.
But the code may evolve and this API may be used more
broadly in the future. Keeping this default implementation
around is very error prone as it may introduce a bug and
hide it on architectures that don't override this API.
Fix this by moving this definition to the jiffies based
cputime headers as it is the only place where it belongs to.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
The full dynticks cputime accounting that we'll soon introduce
will rely on sched_clock(). And its clock can have a per
nanosecond granularity.
To prepare for this, we need to have a cputime_t implementation
that has this precision.
ia64 virtual cputime accounting already uses that granularity
so all we need is to librarize its implementation in the asm
generic headers.
Also librarize the default per jiffy granularity cputime_t
as well so that we can easily pick either implementation
depending on the cputime accounting config we choose.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Pull more s390 patches from Martin Schwidefsky:
"A couple of bug fixes: one of the transparent huge page primitives is
broken, the sched_clock function overflows after 417 days, the XFS
module has grown too large for -fpic and the new pci code has broken
normal channel subsystem notifications."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/chsc: fix SEI usage
s390/time: fix sched_clock() overflow
s390: use -fPIC for module compile
s390/mm: fix pmd_pfn() for thp
Pull xfs bugfixes from Ben Myers:
- fix(es) for compound buffers
- fix for dquot soft timer asserts due to overflow of d_blk_softlimit
- fix for regression in dir v2 code introduced in commit 20f7e9f372
("xfs: factor dir2 block read operations")
* tag 'for-linus-v3.8-rc4' of git://oss.sgi.com/xfs/xfs:
xfs: recalculate leaf entry pointer after compacting a dir2 block
xfs: remove int casts from debug dquot soft limit timer asserts
xfs: fix the multi-segment log buffer format
xfs: fix segment in xfs_buf_item_format_segment
xfs: rename bli_format to avoid confusion with bli_formats
xfs: use b_maps[] for discontiguous buffers
Pull ACPI and power management fixes from Rafael Wysocki:
- cpuidle regression fix related to the initialization of state
kobjects from Krzysztof Mazur.
- cpuidle fix removing some not very useful code and making some
user-visible problems go away at the same time. From Daniel Lezcano.
- ACPI build fix from Yinghai Lu.
* tag 'pm+acpi-for-3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: remove the power_specified field in the driver
ACPI / glue: Fix build with ACPI_GLUE_DEBUG set
cpuidle: fix number of initialized/destroyed states
Dave Jones hit this assert when doing a compile on recent git, with
CONFIG_XFS_DEBUG enabled:
XFS: Assertion failed: (char *)dup - (char *)hdr == be16_to_cpu(*xfs_dir2_data_unused_tag_p(dup)), file: fs/xfs/xfs_dir2_data.c, line: 828
Upon further digging, the tag found by xfs_dir2_data_unused_tag_p(dup)
contained "2" and not the proper offset, and I found that this value was
changed after the memmoves under "Use a stale leaf for our new entry."
in xfs_dir2_block_addname(), i.e.
memmove(&blp[mid + 1], &blp[mid],
(highstale - mid) * sizeof(*blp));
overwrote it.
What has happened is that the previous call to xfs_dir2_block_compact()
has rearranged things; it changes btp->count as well as the
blp array. So after we make that call, we must recalculate the
proper pointer to the leaf entries by making another call to
xfs_dir2_block_leaf_p().
Dave provided a metadump image which led to a simple reproducer
(create a particular filename in the affected directory) and this
resolves the testcase as well as the bug on his live system.
Thanks also to dchinner for looking at this one with me.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Tested-by: Dave Jones <davej@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
The int casts here make it easy to trigger an assert with a large
soft limit. For example, set a >4TB soft limit on an empty volume
to reproduce a (0 > -x) comparison due to an overflow of
d_blk_softlimit.
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Per Dave Chinner suggestion, this patch:
1) Corrects the detection of whether a multi-segment buffer is
still tracking data.
2) Clears all the buffer log formats for a multi-segment buffer.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Not every segment in a multi-segment buffer is dirty in a
transaction and they will not be outputted. The assert in
xfs_buf_item_format_segment() that checks for the at least
one chunk of data in the segment to be used is not necessary
true for multi-segmented buffers.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Rename the bli_format structure to __bli_format to avoid
accidently confusing them with the bli_formats pointer.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Commits starting at 77c1a08 introduced a multiple segment support
to xfs_buf. xfs_trans_buf_item_match() could not find a multi-segment
buffer in the transaction because it was looking at the single segment
block number rather than the multi-segment b_maps[0].bm.bn. This
results on a recursive buffer lock that can never be satisfied.
This patch:
1) Changed the remaining b_map accesses to be b_maps[0] accesses.
2) Renames the single segment b_map structure to __b_map to avoid
future confusion.
Signed-off-by: Mark Tinguely <tinguely@sgi.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ben Myers <bpm@sgi.com>
In commit 281dc5c5ec ("Give up on pushing CC_OPTIMIZE_FOR_SIZE") we
already changed the actual default value, but the help-text still
suggested 'y'. Fix the help text too, for all the same reasons.
Sadly, -Os keeps on generating some very suboptimal code for certain
cases, to the point where any I$ miss upside is swamped by the downside.
The main ones are:
- using "rep movsb" for memcpy, even on CPU's where that is
horrendously bad for performance.
- not honoring branch prediction information, so any I$ footprint you
win from smaller code, you lose from less code density in the I$.
- using divide instructions when that is very expensive.
Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix the build error:
drivers/built-in.o: In function `twl_probe':
drivers/mfd/twl-core.c:1256: undefined reference to `devm_regmap_init_i2c'
make: *** [vmlinux] Error 1
Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Acked-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
[ Samuel is busy, taking it directly - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[ We should make fun of people who can't speel too, but then we'd have
no time for any real work at all - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 1b963c81b1 ("lockdep, rwsem: provide down_write_nest_lock()")
contains a bug in a codepath when CONFIG_DEBUG_LOCK_ALLOC is disabled,
which causes down_read() to be called instead of down_write() by mistake
on such configurations. Fix that.
Reported-and-tested-by: Andrew Clayton <andrew@digital-domain.net>
Reported-and-tested-by: Zlatko Calusic <zlatko.calusic@iskon.hr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull second round of sound fixes from Takashi Iwai:
"Yet a few more fixes popped up in this week.
The biggest change here is the addition of pinctrl support for Atmel,
which turned out to be almost mandatory to make things working.
The rest are a few fixes for M-Audio usb-audio device and a fix for
regression of HD-audio HDMI codecs with alsactl in the recent kernel."
* tag 'sound-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda/hdmi - Work around "alsactl restore" errors
ALSA: usb-audio: selector map for M-Audio FT C400
ALSA: usb-audio: M-Audio FT C400 skip packet quirk
ALSA: usb-audio: correct M-Audio C400 clock source quirk
ALSA: usb - fix race in creation of M-Audio Fast track pro driver
ASoC: atmel-ssc: add pinctrl selection to driver
ARM: at91/dts: add pinctrl support for SSC peripheral
Pull scsi target fixes from Nicholas Bellinger:
"This includes an important >= v3.6 regression bugfix for active I/O
shutdown (Roland), some TMR related failure / corner cases fixes for
long outstanding I/O (Roland), two FCoE target mode fabric fabric role
fixes (MDR), a fix for an incorrect sense code during LUN
communication failure (Dr. Hannes), plus a handful of other minor
fixes.
There are still some outstanding zero-length control CDB regression
fixes that need to be addressed for v3.8, that will be coming in a
follow-up PULL request."
* git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending:
iscsi-target: Fix CmdSN comparison (use cmd->cmd_sn instead of cmd->stat_sn)
target: Release se_cmd when LUN lookup fails for TMR
target: Fix use-after-free in LUN RESET handling
target: Fix missing CMD_T_ACTIVE bit regression for pending WRITEs
tcm_fc: Do not report target role when target is not defined
tcm_fc: Do not indicate retry capability to initiators
target: Use TCM_NO_SENSE for initialisation
target: Introduce TCM_NO_SENSE
target: use correct sense code for LUN communication failure
Pull ext3 and udf fixes from Jan Kara:
"One ext3 performance regression fix and one udf regression fix (oops
on interrupted mount)."
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
UDF: Fix a null pointer dereference in udf_sb_free_partitions
jbd: don't wake kjournald unnecessarily
Pull SuperH fixes from Paul Mundt.
* tag 'sh-for-linus' of git://github.com/pmundt/linux-sh:
sh: ecovec: add sample amixer settings
sh: Fix up stack debugging build.
sh: wire up finit_module syscall.
sh: Fix FDPIC binary loader
sh: clkfwk: bugfix: sh_clk_div_enable() care sh_clk_div_set_rate() if div6
sh: define TASK_UNMAPPED_BASE as a page aligned constant
Frederic Weisbecker
Linus Torvalds
Eric Sandeen
Brian Foster
Mark Tinguely
Kirill Smelkov
Chuansheng Liu
Ralf Baechle
Jiri Kosina