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Zhe Jiang noticed that its possible to underflow pl->events in
prop_norm_percpu() when the value returned by percpu_counter_read() is less
than the error on that read and the period delay > 1. In that case half might
not trigger the batch increment and the value will be identical on the next
iteration, causing the same half to be subtracted again and again.
Fix this by rewriting the division as a single subtraction instead of a
subtraction loop and using percpu_counter_sum() when the value returned by
percpu_counter_read() is smaller than the error.
The latter is still needed if we want pl->events to shrink properly in the
error region.
[akpm@linux-foundation.org: cleanups]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Jiang Zhe <zhe.jiang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This following commit
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=fdf8cb0909b531f9ae8f9b9d7e4eb35ba3505f07
un-inlined a low-level rwsem function, but did not mark it as __sched.
The result is that it now shows up as thread wchan (which also affects
/proc/profile stats). The following simple patch fixes this by properly
marking rwsem_down_failed_common() as a __sched function.
Also in this patch, which is up for discussion, marks down_read() and
down_write() proper as __sched. For profiling, it is pretty much
useless to know that a semaphore is beig help - it is necessary to know
_which_ one. By going up another frame on the stack, the information
becomes much more useful.
In summary, the below change to lib/rwsem.c should be applied; the
changes to kernel/rwsem.c could be applied if other kernel hackers agree
with my proposal that down_read()/down_write() in the profile is not
enough.
[ akpm@linux-foundation.org: build fix ]
Signed-off-by: Livio Soares <livio@eecg.toronto.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Thanks to Dave Young <hidave.darkstar@gmail.com> for pointing out that I
forgot to update the comment when I rewrote kobject_set_name.
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/net-2.6: (27 commits)
[INET]: Fix inet_diag dead-lock regression
[NETNS]: Fix /proc/net breakage
[TEXTSEARCH]: Do not allow zero length patterns in the textsearch infrastructure
[NETFILTER]: fix forgotten module release in xt_CONNMARK and xt_CONNSECMARK
[NETFILTER]: xt_TCPMSS: remove network triggerable WARN_ON
[DECNET]: dn_nl_deladdr() almost always returns no error
[IPV6]: Restore IPv6 when MTU is big enough
[RXRPC]: Add missing select on CRYPTO
mac80211: rate limit wep decrypt failed messages
rfkill: fix double-mutex-locking
mac80211: drop unencrypted frames if encryption is expected
mac80211: Fix behavior of ieee80211_open and ieee80211_close
ieee80211: fix unaligned access in ieee80211_copy_snap
mac80211: free ifsta->extra_ie and clear IEEE80211_STA_PRIVACY_INVOKED
SCTP: Fix build issues with SCTP AUTH.
SCTP: Fix chunk acceptance when no authenticated chunks were listed.
SCTP: Fix the supported extensions paramter
SCTP: Fix SCTP-AUTH to correctly add HMACS paramter.
SCTP: Fix the number of HB transmissions.
[TCP] illinois: Incorrect beta usage
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If a zero length pattern is passed then return EINVAL.
Avoids infinite loops (bm) or invalid memory accesses (kmp).
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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As Herbert Xu pointed out, bytes (chars) with bit 7 (0x80) set are true
with isprint() but they may not be isascii() but be Unicode instead, so
don't try to print them in hex dumps.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This fixes two typos from commit
34358c26a2c96b2a068dc44e0ac602106a466bce.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
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mac80211 has a reference to __bitmap_empty() via bitmap_empty(). In
lib/bitmap.c this is flagged with an EXPORT_SYMBOL(), but this is
ultimately ineffective due to bitmap.o being linked in lib-y, resulting in:
ERROR: "__bitmap_empty" [net/mac80211/mac80211.ko] undefined!
Moving bitmap.o to obj-y fixes this up.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Cc: "John W. Linville" <linville@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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crypto/crc32.c:chksum_final() is computing the digest as
*(__le32 *)out = ~cpu_to_le32(mctx->crc);
so the low-level crc32c_le routines should just keep
the crc in cpu order, otherwise it is getting swabbed
one too many times on big-endian machines.
Signed-off-by: Benny Halevy <bhalevy@fs1.bhalevy.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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When a bitmap is empty bitmap_scnlistprintf() would leave the buffer
uninitialized. Set it to an empty string in this case.
I didn't see any in normal kernel callers hitting this, but some custom
debug code of mine did.
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This should catch any duplicate names before we try to tell sysfs to
rename the object. This happens a lot with older versions of udev and
the network rename scripts.
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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The __deprecated marker is quite useful in highlighting the remnants of
old APIs that want removing.
However, it is quite normal for one or more years to pass, before the
(usually ancient, bitrotten) code in question is either updated or
deleted.
Thus, like __must_check, add a Kconfig option that permits the silencing
of this compiler warning.
This change mimics the ifdef-ery and Kconfig defaults of MUST_CHECK as
closely as possible.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* git://git.infradead.org/mtd-2.6:
[MTD] [NOR] Fix deadlock in Intel chip driver caused by get_chip recursion
[JFFS2] Fix return value from jffs2_write_end()
[MTD] [OneNAND] Fix wrong free the static address in onenand_sim
[MTD] [NAND] Replace -1 with -EBADMSG in nand error correction code
[RSLIB] BUG() when passing illegal parameters to decode_rs8() or decode_rs16()
[MTD] [NAND] treat any negative return value from correct() as an error
[MTD] [NAND] nandsim: bugfix in initialization
[MTD] Fix typo in Alauda config option help text.
[MTD] [NAND] add s3c2440-specific read_buf/write_buf
[MTD] [OneNAND] onenand-sim: fix kernel-doc and typos
[JFFS2] Tidy up fix for ACL/permissions problem.
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Add a Kconfig entry which will toggle some sanity checks on the sg
entry and tables.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Magic numerical values are just bad style. Particularly so when
undocumented.
Signed-off-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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Returning -ERANGE should never happen.
Signed-off-by: Jörn Engel <joern@logfs.org>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
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Spelling fix in lib/.
Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
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Replace an irrelevant include of bug.h with the more appropriate
includes of slab.h and module.h.
it's not as if the original inclusion is an error, it's simply not
related to the contents of that source file, while the other two are.
compile-tested on i386.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
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Fix the various misspellings of "system", controller", "interrupt" and
"[un]necessary".
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
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Begin infrastructure for kernel code samples in the samples/ directory.
Add its Kconfig and Kbuild files.
Source its Kconfig file in all arch/ Kconfigs.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Some of the per-cpu counters and thus their locks are accessed from IRQ
contexts. This can cause a deadlock if it interrupts a cpu-offline thread
which is transferring a dead-cpu's counts to the global counter.
Add appropriate IRQ protection in the cpu-hotplug callback path.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The task_struct->pid member is going to be deprecated, so start
using the helpers (task_pid_nr/task_pid_vnr/task_pid_nr_ns) in
the kernel.
The first thing to start with is the pid, printed to dmesg - in
this case we may safely use task_pid_nr(). Besides, printks produce
more (much more) than a half of all the explicit pid usage.
[akpm@linux-foundation.org: git-drm went and changed lots of stuff]
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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remove asm/bitops.h includes
including asm/bitops directly may cause compile errors. don't include it
and include linux/bitops instead. next patch will deny including asm header
directly.
Cc: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Cause writes to cpuset "cpus" file to update cpus_allowed for member tasks:
- collect batches of tasks under tasklist_lock and then call
set_cpus_allowed() on them outside the lock (since this can sleep).
- add a simple generic priority heap type to allow efficient collection
of batches of tasks to be processed without duplicating or missing any
tasks in subsequent batches.
- make "cpus" file update a no-op if the mask hasn't changed
- fix race between update_cpumask() and sched_setaffinity() by making
sched_setaffinity() post-check that it's not running on any cpus outside
cpuset_cpus_allowed().
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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To be consistent with the use of attributes in the rest of the kernel
replace all use of __attribute_pure__ with __pure and delete the definition
of __attribute_pure__.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Acked-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block:
[SCSI] Remove full sg table memset()
[SCSI] ide-scsi: remove usage of sg_last()
Fix loop terminating conditions in fill_sg().
[BLOCK] Clear sg entry before filling in blk_rq_map_sg()
IA64: iommu uses sg_next with an invalid sg element
cciss: disable DMA refetch on Smart Array P600
swiotlb: fix map_sg failure handling
SPARC64: fix iommu sg chaining
[SCSI] ide-scsi: use scsi_sg_count() instead of ->use_sg
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Be explicit about printing hex.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Negative shifts are not allowed in C (the result is undefined). Same thing
with full-width shifts.
It works on most platforms but not on the VAX with gcc 4.0.1 (it results in an
"operand reserved" fault).
Shifting by more than the width of the value on the left is also not
allowed. I think the extra '>> 1' tacked on at the end in the original
code was an attempt to work around that. Getting rid of that is an extra
feature of this patch.
Here's the chapter and verse, taken from the final draft of the C99
standard ("6.5.7 Bitwise shift operators", paragraph 3):
"The integer promotions are performed on each of the operands. The
type of the result is that of the promoted left operand. If the
value of the right operand is negative or is greater than or equal
to the width of the promoted left operand, the behavior is
undefined."
Thank you to Jan-Benedict Glaw, Christoph Hellwig, Maciej Rozycki, Pekka
Enberg, Andreas Schwab, and Christoph Lameter for review. Special thanks
to Andreas for spotting that my fix only removed half the undefined
behaviour.
Signed-off-by: Peter Lund <firefly@vax64.dk>
Christoph Lameter <clameter@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Andreas Schwab <schwab@suse.de>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: WU Fengguang <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Various architectures may call bust_spinlocks() recursively; the function
itself, however, doesn't appear to be meant to be called in this manner.
Nevertheless, this doesn't appear to be a problem as long as
bust_spinlocks(0) doesn't get called twice in a row (otherwise,
unblank_screen() may enter the scheduler). However, at least on i386 die()
has been capable of returning (and on other architectures this should
really be that way, too) when notify_die() returns NOTIFY_STOP.
Short of getting a reply to a respective query, this patch makes
bust_spinlocks() increment/decrement oops_in_progress, and wake klogd only
when the count drops back to zero.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Hello, I fixed and tested a small bug in lib/sort.c file, heap sort
function.
The fix avoids unnecessary swap of contents when i is 0 (saves few loads
and stores), which happens every time sort function is called. I felt the
fix is worth bringing it to your attention given the importance and
frequent use of the sort function.
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Every file should include the headers containing the prototypes for its global
functions (in this case ioremap_page_range()).
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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gracefully
It would be nice if the argv_split library function could gracefully handle
a NULL pointer in the argcp parameter, so as to allow functions using it
that did not care about the value of argc to not have to declare a useless
variable. This patch accomplishes that. Tested by me, with successful
results.
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Satyam Sharma <satyam@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Slab constructors currently have a flags parameter that is never used. And
the order of the arguments is opposite to other slab functions. The object
pointer is placed before the kmem_cache pointer.
Convert
ctor(void *object, struct kmem_cache *s, unsigned long flags)
to
ctor(struct kmem_cache *s, void *object)
throughout the kernel
[akpm@linux-foundation.org: coupla fixes]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Given a set of objects, floating proportions aims to efficiently give the
proportional 'activity' of a single item as compared to the whole set. Where
'activity' is a measure of a temporal property of the items.
It is efficient in that it need not inspect any other items of the set
in order to provide the answer. It is not even needed to know how many
other items there are.
It has one parameter, and that is the period of 'time' over which the
'activity' is measured.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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provide a way to tell lockdep about percpu_counters that are supposed to be
used from irq safe contexts.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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alloc_percpu can fail, propagate that error.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Provide an accurate version of percpu_counter_read.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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s/percpu_counter_sum/&_positive/
Because its consitent with percpu_counter_read*
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Provide a method to set a percpu counter to a specified value.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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percpu_counter is a s64 counter, make _add consitent.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Because the current batch setup has an quadric error bound on the counter,
allow for an alternative setup.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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s/percpu_counter_mod/percpu_counter_add/
Because its a better name, _mod implies modulo.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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sg list elements might not be continuous.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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* 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block: (63 commits)
Fix memory leak in dm-crypt
SPARC64: sg chaining support
SPARC: sg chaining support
PPC: sg chaining support
PS3: sg chaining support
IA64: sg chaining support
x86-64: enable sg chaining
x86-64: update pci-gart iommu to sg helpers
x86-64: update nommu to sg helpers
x86-64: update calgary iommu to sg helpers
swiotlb: sg chaining support
i386: enable sg chaining
i386 dma_map_sg: convert to using sg helpers
mmc: need to zero sglist on init
Panic in blk_rq_map_sg() from CCISS driver
remove sglist_len
remove blk_queue_max_phys_segments in libata
revert sg segment size ifdefs
Fixup u14-34f ENABLE_SG_CHAINING
qla1280: enable use_sg_chaining option
...
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This patch marks a number of allocations that are either short-lived such as
network buffers or are reclaimable such as inode allocations. When something
like updatedb is called, long-lived and unmovable kernel allocations tend to
be spread throughout the address space which increases fragmentation.
This patch groups these allocations together as much as possible by adding a
new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be
reclaimed on demand, but not moved. i.e. they can be migrated by deleting
them and re-reading the information from elsewhere.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A while back, Nick Piggin introduced a patch to reduce the node memory
usage for small files (commit cfd9b7df4abd3257c9e381b0e445817b26a51c0c):
-#define RADIX_TREE_MAP_SHIFT 6
+#define RADIX_TREE_MAP_SHIFT (CONFIG_BASE_SMALL ? 4 : 6)
Unfortunately, he didn't take into account the fact that the
calculation of the maximum path was based on an assumption of having
to round up:
#define RADIX_TREE_MAX_PATH (RADIX_TREE_INDEX_BITS/RADIX_TREE_MAP_SHIFT + 2)
So, if CONFIG_BASE_SMALL is set, you will end up with a
RADIX_TREE_MAX_PATH that is one greater than necessary. The practical
upshot of this is just a bit of wasted memory (one long in the
height_to_maxindex array, an extra pre-allocated radix tree node per
cpu, and extra stack usage in a couple of functions), but it seems
worth getting right.
It's also worth noting that I never build with CONFIG_BASE_SMALL.
What I did to test this was duplicate the code in a small user-space
program and check the results of the calculations for max path and the
contents of the height_to_maxindex array.
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rather than sign direct radix-tree pointers with a special bit, sign the
indirect one that hangs off the root. This means that, given a lookup_slot
operation, the invalid result will be differentiated from the valid
(previously, valid results could have the bit either set or clear).
This does not affect slot lookups which occur under lock -- they can never
return an invalid result. Is needed in future for lockless pagecache.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Introduce radix_tree_next_hole(root, index, max_scan) to scan radix tree for
the first hole. It will be used in interleaved readahead.
The implementation is dumb and obviously correct. It can help debug(and
document) the possible smart one in future.
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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