* 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, asm: Use a lower case name for the end macro in atomic64_386_32.S
x86, asm: Refactor atomic64_386_32.S to support old binutils and be cleaner
x86: Document __phys_reloc_hide() usage in __pa_symbol()
x86, apic: Map the local apic when parsing the MP table.
It's wrong for several reasons, but the most direct one is that the
fault may be for the stack accesses to set up a previous SIGBUS. When
we have a kernel exception, the kernel exception handler does all the
fixups, not some user-level signal handler.
Even apart from the nested SIGBUS issue, it's also wrong to give out
kernel fault addresses in the signal handler info block, or to send a
SIGBUS when a system call already returns EFAULT.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
.. which didn't show up in my tests because it's a no-op on x86-64 and
most other architectures. But we enter the function with the last-level
page table mapped, and should unmap it at exit.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a rather minimally invasive patch to solve the problem of the
user stack growing into a memory mapped area below it. Whenever we fill
the first page of the stack segment, expand the segment down by one
page.
Now, admittedly some odd application might _want_ the stack to grow down
into the preceding memory mapping, and so we may at some point need to
make this a process tunable (some people might also want to have more
than a single page of guarding), but let's try the minimal approach
first.
Tested with trivial application that maps a single page just below the
stack, and then starts recursing. Without this, we will get a SIGSEGV
_after_ the stack has smashed the mapping. With this patch, we'll get a
nice SIGBUS just as the stack touches the page just above the mapping.
Requested-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 3bcf3860a4 (and the
accompanying commit c1e5c95402 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).
The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.
Fix up various conflicts due to later fsnotify work.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm: (33 commits)
dm mpath: support discard
dm stripe: support discards
dm: split discard requests on target boundaries
dm stripe: optimize sector division
dm stripe: move sector translation to a function
dm: error return error for discards
dm delay: support discard
dm: zero silently drop discards
dm: use dm_target_offset macro
dm: factor out max_io_len_target_boundary
dm: use common __issue_target_request for flush and discard support
dm: linear support discard
dm crypt: simplify crypt_ctr
dm crypt: simplify crypt_config destruction logic
dm: allow autoloading of dm mod
dm: rename map_info flush_request to target_request_nr
dm ioctl: refactor dm_table_complete
dm snapshot: implement merge
dm: do not initialise full request queue when bio based
dm ioctl: make bio or request based device type immutable
...
* 'for-linus' of git://neil.brown.name/md:
Further tidyup of raid6 naming in lib/raid6
Make lib/raid6/test build correctly.
Rename raid6 files now they're in a 'raid6' directory.
* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
i2c: I2C bus multiplexer driver pca954x
i2c: Multiplexed I2C bus core support
i2c: Use a separate mutex for userspace client lists
i2c: Make i2c_default_probe self-sufficient
i2c: Drop dummy variable
i2c: Move adapter locking helpers to i2c-core
V4L/DVB: Use custom I2C probing function mechanism
i2c: Add support for custom probe function
i2c-dev: Use memdup_user
i2c-dev: Remove unnecessary kmalloc casts
* 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (22 commits)
param: don't deref arg in __same_type() checks
param: update drivers/acpi/debug.c to new scheme
param: use module_param in drivers/message/fusion/mptbase.c
ide: use module_param_named rather than module_param_call
param: update drivers/char/ipmi/ipmi_watchdog.c to new scheme
param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes.
param: lock myri10ge_fw_name against sysfs changes.
param: simple locking for sysfs-writable charp parameters
param: remove unnecessary writable charp
param: add kerneldoc to moduleparam.h
param: locking for kernel parameters
param: make param sections const.
param: use free hook for charp (fix leak of charp parameters)
param: add a free hook to kernel_param_ops.
param: silence .init.text references from param ops
Add param ops struct for hvc_iucv driver.
nfs: update for module_param_named API change
AppArmor: update for module_param_named API change
param: use ops in struct kernel_param, rather than get and set fns directly
param: move the EXPORT_SYMBOL to after the definitions.
...
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
ASoC: add AD1980 obsolete information
ASoC: register cache should be 1 byte aligned for 1 byte long register
ALSA: hda - Adding support for new IDT 92HD87XX codecs
ASoC: Fix inverted mute controls for WM8580
ALSA: HDA: Use model=auto for LG R510
ALSA: hda - Update model entries in HD-Audio-Models.txt
ALSA: hda: document VIA models
ALSA: hda - patch_nvhdmi.c: Add missing codec IDs, unify names
ALSA: hda - add support for Conexant CX20584
ALSA: hda - New snd-hda-intel model/pin config for hp dv7-4000
ALSA: hda - Fix missing stream for second ADC on Realtek ALC260 HDA codec
ALSA: hda - Make converter setups sticky
ALSA: hda - Add support for Acer ZGA ALC271 (1025:047c)
sound/oss: Adjust confusing if indentation
sound: oss: au1550_ac97.c removed duplicated #include
ASoC: Fix for changed Eureka Kconfig symbol names
The current computation, introduced with f12a15be63, of FSEC_PER_SEC using
the multiplication of (FSEC_PER_NSEC * NSEC_PER_SEC) is performed only
with 32bit integers on small machines, resulting in an overflow and a
*very* short intervals being programmed. An interrupt storm follows.
Note that we also have to specify FSEC_PER_SEC as being long long to
overcome the same limitations.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The tv_nsec is a long and when added to the shifted interval it can wrap
and become negative which later causes looping problems in the
getrawmonotonic(). The edge case occurs when the system has slept for
a short period of time of ~2 seconds.
A trace printk of the values in this patch illustrate the problem:
ftrace time stamp: log
43.716079: logarithmic_accumulation: raw: 3d0913 tv_nsec d687faa
43.718513: logarithmic_accumulation: raw: 3d0913 tv_nsec da588bd
43.722161: logarithmic_accumulation: raw: 3d0913 tv_nsec de291d0
46.349925: logarithmic_accumulation: raw: 7a122600 tv_nsec e1f9ae3
46.349930: logarithmic_accumulation: raw: 1e848980 tv_nsec 8831c0e3
The kernel starts looping at 46.349925 in the getrawmonotonic() due to
the negative value from adding the raw value to tv_nsec.
A simple solution is to accumulate into a u64, and then normalize it
to a timespec_t.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
[ Reworked variable names and simplified some of the code. - John ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use no_printk() for disabled gdbstub debugging functions to maintain side
effect checking.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a dummy printk function for the maintenance of unused printks through gcc
format checking, and also so that side-effect checking is maintained too.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Don't try and #include <linux/slab.h> in lib/inflate.c from the bootloader code
as linux/slab.h hauls in function defs that aren't available in the bootloader
code and may also haul in conflicting functions.
To fix this, make the inclusion of linux/slab.h contingent on NO_INFLATE_MALLOC
as are the usages of kmalloc() and kfree().
In MN10300, this causes the following errors:
In file included from include/linux/string.h:21,
from include/linux/bitmap.h:8,
from include/linux/nodemask.h:93,
from include/linux/mmzone.h:16,
from include/linux/gfp.h:4,
from include/linux/slab.h:12,
from arch/mn10300/boot/compressed/../../../../lib/inflate.c:106,
from arch/mn10300/boot/compressed/misc.c:170:
/warthog/am33/linux-2.6-mn10300/arch/mn10300/include/asm/string.h:19: error: conflicting types for 'memset'
arch/mn10300/boot/compressed/misc.c:59: error: previous definition of 'memset' was here
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Permit .GCC-command-line sections in modules. Otherwise modpost says things
like:
WARNING: drivers/mtd/chips/map_ram.o (.GCC-command-line): unexpected non-allocatable section.
Did you forget to use "ax"/"aw" in a .S file?
Note that for example <linux/init.h> contains
section definitions for use in .S files.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the newer compilers, size_t and ssize_t are expected to be (un)signed int
rather than (un)signed long.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A change to the RTC routines in the MN10300 arch used set_rtc_mms() when it
meant set_rtc_mmss(). This results in an error due to a reference of an
undefined symbol.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pcc_cpu_info is a percpu pointer but was missing __percpu markup.
Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Dave Jones <davej@redhat.com>
* 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (55 commits)
io-mapping: move asm include inside the config option
vgaarb: drop vga.h include
drm/radeon: Add probing of clocks from device-tree
drm/radeon: drop old and broken mesa warning
drm/radeon: Fix pci_map_page() error checking
drm: Remove count_lock for calling lastclose() after 58474713 (v2)
drm/radeon/kms: allow FG_ALPHA_VALUE on r5xx
drm/radeon/kms: another r6xx/r7xx CS checker fix
DRM: Replace kmalloc/memset combos with kzalloc
drm: expand gamma_set
drm/edid: Split mode lists out to their own header for readability
drm/edid: Rewrite mode parse to use the generic detailed block walk
drm/edid: Add detailed block walk for VTB extensions
drm/edid: Add detailed block walk for CEA extensions
drm: Remove unused fields from drm_display_info
drm: Use ENOENT consistently for the error return for an unmatched handle.
drm/radeon/kms: mark 3D power states as performance
drm: Only set DPMS once on the CRTC not after every encoder.
drm/radeon/kms: add additional quirk for Acer rv620 laptop
drm: Propagate error code from fb_create()
...
Fix up trivial conflicts in drivers/gpu/drm/drm_edid.c
Some nice improvements were made to rwsem in commit:
424acaaeb3
rwsem: wake queued readers when writer blocks on active read lock
but this change overlooked that ia64 had defined RWSEM_WAITING_BIAS
as an unsigned value, while the new code required a signed value (as
it is in every other architecture).
This fix suggested by the original patch author: Michel Lespinasse.
Signed-off-by: Tony Luck <tony.luck@intel.com>
* 'stable/xen-swiotlb-0.8.6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
x86: Detect whether we should use Xen SWIOTLB.
pci-swiotlb-xen: Add glue code to setup dma_ops utilizing xen_swiotlb_* functions.
swiotlb-xen: SWIOTLB library for Xen PV guest with PCI passthrough.
xen/mmu: inhibit vmap aliases rather than trying to clear them out
vmap: add flag to allow lazy unmap to be disabled at runtime
xen: Add xen_create_contiguous_region
xen: Rename the balloon lock
xen: Allow unprivileged Xen domains to create iomap pages
xen: use _PAGE_IOMAP in ioremap to do machine mappings
Fix up trivial conflicts (adding both xen swiotlb and xen pci platform
driver setup close to each other) in drivers/xen/{Kconfig,Makefile} and
include/xen/xen-ops.h
mspro_block_remove() is called from detect thread that first calls the
mspro_block_stop(), which stops the request queue. If we call
del_gendisk() with the queue stopped we get a deadlock.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Fix mmc_test_alloc_mem.
- Use nr_free_buffer_pages() instead of sysinfo.totalram to determine
total lowmem pages.
- Change variables containing memory sizes to unsigned long.
- Limit maximum test area size to 128MiB because that is the maximum MMC
high capacity erase size (the maxmium SD allocation unit size is just
4MiB)
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mmc_test provides tests aimed at testing SD/MMC hosts. This patch adds
performance tests.
It is advantageous to have performance tests in a kernel
module like mmc_test for the following reasons:
- transfer times can be measured very accurately
- arbitrarily large transfers are possible
- the effect of contiguous vs scattered pages
can be determined
The new tests are:
23. Best-case read performance
24. Best-case write performance
25. Best-case read performance into scattered pages
26. Best-case write performance from scattered pages
27. Single read performance by transfer size
28. Single write performance by transfer size
29. Single trim performance by transfer size
30. Consecutive read performance by transfer size
31. Consecutive write performance by transfer size
32. Consecutive trim performance by transfer size
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Secure discard is implemented by Secure Trim if the discard is unaligned
or Secure Erase otherwise.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Disable the data (busy) timeout for erases and set the MMC_CAP_ERASE
capability.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Enable MMC to service discard requests. In the case of SD and MMC cards
that do not support trim, discards become erases. In the case of cards
(MMC) that only allow erases in multiples of erase group size, round to
the nearest completely discarded erase group.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SD/MMC cards tend to support an erase operation. In addition, eMMC v4.4
cards can support secure erase, trim and secure trim operations that are
all variants of the basic erase command.
SD/MMC device attributes "erase_size" and "preferred_erase_size" have been
added.
"erase_size" is the minimum size, in bytes, of an erase operation. For
MMC, "erase_size" is the erase group size reported by the card. Note that
"erase_size" does not apply to trim or secure trim operations where the
minimum size is always one 512 byte sector. For SD, "erase_size" is 512
if the card is block-addressed, 0 otherwise.
SD/MMC cards can erase an arbitrarily large area up to and
including the whole card. When erasing a large area it may
be desirable to do it in smaller chunks for three reasons:
1. A single erase command will make all other I/O on the card
wait. This is not a problem if the whole card is being erased, but
erasing one partition will make I/O for another partition on the
same card wait for the duration of the erase - which could be a
several minutes.
2. To be able to inform the user of erase progress.
3. The erase timeout becomes too large to be very useful.
Because the erase timeout contains a margin which is multiplied by
the size of the erase area, the value can end up being several
minutes for large areas.
"erase_size" is not the most efficient unit to erase (especially for SD
where it is just one sector), hence "preferred_erase_size" provides a good
chunk size for erasing large areas.
For MMC, "preferred_erase_size" is the high-capacity erase size if a card
specifies one, otherwise it is based on the capacity of the card.
For SD, "preferred_erase_size" is the allocation unit size specified by
the card.
"preferred_erase_size" is in bytes.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 83ba7b071f ("writeback: simplify the write back thread queue")
broke writeback_in_progress() as in that commit we started to remove work
items from the list at the moment we start working on them and not at the
moment they are finished. Thus if the flusher thread was doing some work
but there was no other work queued, writeback_in_progress() returned
false. This could in particular cause unnecessary queueing of background
writeback from balance_dirty_pages() or writeout work from
writeback_sb_if_idle().
This patch fixes the problem by introducing a bit in the bdi state which
indicates that the flusher thread is processing some work and uses this
bit for writeback_in_progress() test.
NOTE: Both callsites of writeback_in_progress() (namely,
writeback_inodes_sb_if_idle() and balance_dirty_pages()) would actually
need a different information than what writeback_in_progress() provides.
They would need to know whether *the kind of writeback they are going to
submit* is already queued. But this information isn't that simple to
provide so let's fix writeback_in_progress() for the time being.
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unify the logic for kupdate and non-kupdate cases. There won't be
starvation because the inodes requeued into b_more_io will later be
spliced _after_ the remaining inodes in b_io, hence won't stand in the way
of other inodes in the next run.
It avoids unnecessary redirty_tail() calls, hence the update of
i_dirtied_when. The timestamp update is undesirable because it could
later delay the inode's periodic writeback, or may exclude the inode from
the data integrity sync operation (which checks timestamp to avoid extra
work and livelock).
===
How the redirty_tail() comes about:
It was a long story.. This redirty_tail() was introduced with
wbc.more_io. The initial patch for more_io actually does not have the
redirty_tail(), and when it's merged, several 100% iowait bug reports
arised:
reiserfs:
http://lkml.org/lkml/2007/10/23/93
jfs:
commit 29a424f283
JFS: clear PAGECACHE_TAG_DIRTY for no-write pages
ext2:
http://www.spinics.net/linux/lists/linux-ext4/msg04762.html
They are all old bugs hidden in various filesystems that become "visible"
with the more_io patch. At the time, the ext2 bug is thought to be
"trivial", so not fixed. Instead the following updated more_io patch with
redirty_tail() is merged:
http://www.spinics.net/linux/lists/linux-ext4/msg04507.html
This will in general prevent 100% on ext2 and possibly other unknown FS bugs.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was not a bug, since b_io is empty for kupdate writeback. The next
patch will do requeue_io() for non-kupdate writeback, so let's fix it.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Martin Bligh <mbligh@google.com>
Cc: Michael Rubin <mrubin@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid delaying writeback for an expire inode with lots of dirty pages, but
no active dirtier at the moment. Previously we only do that for the
kupdate case.
Any filesystem that does delayed allocation or unwritten extent conversion
after IO completion will cause this - for example, XFS.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Split get_dirty_limits() into global_dirty_limits()+bdi_dirty_limit(), so
that the latter can be avoided when under global dirty background
threshold (which is the normal state for most systems).
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reducing the number of times balance_dirty_pages calls global_page_state
reduces the cache references and so improves write performance on a
variety of workloads.
'perf stats' of simple fio write tests shows the reduction in cache
access. Where the test is fio 'write,mmap,600Mb,pre_read' on AMD AthlonX2
with 3Gb memory (dirty_threshold approx 600 Mb) running each test 10
times, dropping the fasted & slowest values then taking the average &
standard deviation
average (s.d.) in millions (10^6)
2.6.31-rc8 648.6 (14.6)
+patch 620.1 (16.5)
Achieving this reduction is by dropping clip_bdi_dirty_limit as it rereads
the counters to apply the dirty_threshold and moving this check up into
balance_dirty_pages where it has already read the counters.
Also by rearrange the for loop to only contain one copy of the limit tests
allows the pdflush test after the loop to use the local copies of the
counters rather than rereading them.
In the common case with no throttling it now calls global_page_state 5
fewer times and bdi_stat 2 fewer.
Fengguang:
This patch slightly changes behavior by replacing clip_bdi_dirty_limit()
with the explicit check (nr_reclaimable + nr_writeback >= dirty_thresh) to
avoid exceeding the dirty limit. Since the bdi dirty limit is mostly
accurate we don't need to do routinely clip. A simple dirty limit check
would be enough.
The check is necessary because, in principle we should throttle everything
calling balance_dirty_pages() when we're over the total limit, as said by
Peter.
We now set and clear dirty_exceeded not only based on bdi dirty limits,
but also on the global dirty limit. The global limit check is added in
place of clip_bdi_dirty_limit() for safety and not intended as a behavior
change. The bdi limits should be tight enough to keep all dirty pages
under the global limit at most time; occasional small exceeding should be
OK though. The change makes the logic more obvious: the global limit is
the ultimate goal and shall be always imposed.
We may now start background writeback work based on outdated conditions.
That's safe because the bdi flush thread will (and have to) double check
the states. It reduces overall overheads because the test based on old
states still have good chance to be right.
[akpm@linux-foundation.org] fix uninitialized dirty_exceeded
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix kconfig dependency warning for PC8736x_GPIO by restricting it to
X86_32.
warning: (SCx200_GPIO && SCx200 || PC8736x_GPIO && X86) selects NSC_GPIO which has unmet direct dependencies (X86_32)
NSC_GPIO is X86_32 only. The other driver (SCx200_GPIO) that selects
NSC_GPIO is X86_32 only (indirectly, since SCx200 depends on X86_32), so
limit this driver also.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Jordan Crouse <jordan.crouse@amd.com>
Cc: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
