- 13 5月, 2010 1 次提交
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由 Paul Mundt 提交于
Now that the definitions have been consolidated in an alternate header, update the template accordingly. Signed-off-by: NPaul Mundt <lethal@linux-sh.org>
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- 12 5月, 2010 1 次提交
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由 Robin Holt 提交于
Originally, commit d899bf7b ("procfs: provide stack information for threads") attempted to introduce a new feature for showing where the threadstack was located and how many pages are being utilized by the stack. Commit c44972f1 ("procfs: disable per-task stack usage on NOMMU") was applied to fix the NO_MMU case. Commit 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on 64-bit") was applied to fix a bug in ia32 executables being loaded. Commit 9ebd4eba ("procfs: fix /proc/<pid>/stat stack pointer for kernel threads") was applied to fix a bug which had kernel threads printing a userland stack address. Commit 1306d603 ('proc: partially revert "procfs: provide stack information for threads"') was then applied to revert the stack pages being used to solve a significant performance regression. This patch nearly undoes the effect of all these patches. The reason for reverting these is it provides an unusable value in field 28. For x86_64, a fork will result in the task->stack_start value being updated to the current user top of stack and not the stack start address. This unpredictability of the stack_start value makes it worthless. That includes the intended use of showing how much stack space a thread has. Other architectures will get different values. As an example, ia64 gets 0. The do_fork() and copy_process() functions appear to treat the stack_start and stack_size parameters as architecture specific. I only partially reverted c44972f1 ("procfs: disable per-task stack usage on NOMMU") . If I had completely reverted it, I would have had to change mm/Makefile only build pagewalk.o when CONFIG_PROC_PAGE_MONITOR is configured. Since I could not test the builds without significant effort, I decided to not change mm/Makefile. I only partially reverted 89240ba0 ("x86, fs: Fix x86 procfs stack information for threads on 64-bit") . I left the KSTK_ESP() change in place as that seemed worthwhile. Signed-off-by: NRobin Holt <holt@sgi.com> Cc: Stefani Seibold <stefani@seibold.net> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 11 5月, 2010 5 次提交
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由 Eric Miao 提交于
Signed-off-by: NEric Miao <eric.y.miao@gmail.com>
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由 Eric Miao 提交于
The only use of corgi_ssp.c is corgi_ts.c, which is now deprecated and removed. Remove corgi_ssp.c and corgi_lcd.c and their relevant function declarations and data structures. Signed-off-by: NEric Miao <eric.y.miao@gmail.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Pavel Machek <pavel@ucw.cz>
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由 Joerg Roedel 提交于
This patch adds a command line option to tell the AMD IOMMU driver to not initialize any IOMMU it finds. Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
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由 Paul E. McKenney 提交于
The existing Documentation/RCU/stallwarn.txt has proven unhelpful, so rework it a bit. In particular, show how to interpret the stall-warning messages. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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由 Paul E. McKenney 提交于
Lai Jiangshan noted that up to 10% of the RCU_SOFTIRQ are spurious, and traced this down to the fact that the current grace-period machinery will uselessly raise RCU_SOFTIRQ when a given CPU needs to go through a quiescent state, but has not yet done so. In this situation, there might well be nothing that RCU_SOFTIRQ can do, and the overhead can be worth worrying about in the ksoftirqd case. This patch therefore avoids raising RCU_SOFTIRQ in this situation. Changes since v1 (http://lkml.org/lkml/2010/3/30/122 from Lai Jiangshan): o Omit the rcu_qs_pending() prechecks, as they aren't that much less expensive than the quiescent-state checks. o Merge with the set_need_resched() patch that reduces IPIs. o Add the new n_rp_report_qs field to the rcu_pending tracing output. o Update the tracing documentation accordingly. Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 07 5月, 2010 2 次提交
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由 Hans Verkuil 提交于
Signed-off-by: NHans Verkuil <hverkuil@xs4all.nl> Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>
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由 Tejun Heo 提交于
Currently migration_thread is serving three purposes - migration pusher, context to execute active_load_balance() and forced context switcher for expedited RCU synchronize_sched. All three roles are hardcoded into migration_thread() and determining which job is scheduled is slightly messy. This patch kills migration_thread and replaces all three uses with cpu_stop. The three different roles of migration_thread() are splitted into three separate cpu_stop callbacks - migration_cpu_stop(), active_load_balance_cpu_stop() and synchronize_sched_expedited_cpu_stop() - and each use case now simply asks cpu_stop to execute the callback as necessary. synchronize_sched_expedited() was implemented with private preallocated resources and custom multi-cpu queueing and waiting logic, both of which are provided by cpu_stop. synchronize_sched_expedited_count is made atomic and all other shared resources along with the mutex are dropped. synchronize_sched_expedited() also implemented a check to detect cases where not all the callback got executed on their assigned cpus and fall back to synchronize_sched(). If called with cpu hotplug blocked, cpu_stop already guarantees that and the condition cannot happen; otherwise, stop_machine() would break. However, this patch preserves the paranoid check using a cpumask to record on which cpus the stopper ran so that it can serve as a bisection point if something actually goes wrong theree. Because the internal execution state is no longer visible, rcu_expedited_torture_stats() is removed. This patch also renames cpu_stop threads to from "stopper/%d" to "migration/%d". The names of these threads ultimately don't matter and there's no reason to make unnecessary userland visible changes. With this patch applied, stop_machine() and sched now share the same resources. stop_machine() is faster without wasting any resources and sched migration users are much cleaner. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NPeter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Josh Triplett <josh@freedesktop.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dimitri Sivanich <sivanich@sgi.com>
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- 06 5月, 2010 1 次提交
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由 Sergei Shtylyov 提交于
Commit 6bfff31e (libata: kill probe_ent and related helpers) killed ata_device_add() but didn't remove references to it from the libata developer's guide. Commits 9363c382 (libata: rename SFF functions) and 5682ed33 (libata: rename SFF port ops) renamed the taskfile access methods but didn't update the developer's guide. Commit c9f75b04 (libata: kill ata_noop_dev_select()) didn't update the developer's guide as well. The guide also refers to the long gone ata_pio_data_xfer_noirq(), ata_pio_data_xfer(), and ata_mmio_data_xfer() -- replace those by the modern ata_sff_data_xfer_noirq(), ata_sff_data_xfer(), and ata_sff_data_xfer32(). Also, remove the reference to non-existant ata_port_stop()... Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
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- 05 5月, 2010 1 次提交
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由 Li Zefan 提交于
Make it clear that event-list is a comma separated list of events. Reported-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4B2F154C.2060503@cn.fujitsu.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 04 5月, 2010 2 次提交
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由 Wolfram Sang 提交于
After discovering that a lot of i2c-drivers leave the pointer to their clientdata dangling, it was decided to let the core handle this issue. It is assumed that the core may access the private data after remove() as there are no guarantees for the lifetime of such pointers anyhow (see thread starting at http://lkml.org/lkml/2010/3/21/68) Signed-off-by: NWolfram Sang <w.sang@pengutronix.de> Signed-off-by: NJean Delvare <khali@linux-fr.org>
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由 Florian Ragwitz 提交于
In older versions of the elantech hardware/firmware those bits always were unset, so it didn't actually matter, but newer versions seem to use those high bits for something else, screwing up the coordinates we report to the input layer for those devices. Signed-off-by: NFlorian Ragwitz <rafl@debian.org> Signed-off-by: NDmitry Torokhov <dtor@mail.ru>
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- 30 4月, 2010 1 次提交
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由 Hector Palacios 提交于
The sample application spidev_test.c is using SPI_IOC_MESSAGE ioctl to do an SPI transfer. This ioctl returns the number of bytes successfully transmitted or a negative error code upon erroneous completion. The application however is returning an error if the result of the ioclt if the return value is 1. This makes the application to fail upon 1-byte length transfers. Signed-off-by: NHector Palacios <hector.palacios@digi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
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- 28 4月, 2010 1 次提交
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由 Chase Douglas 提交于
The mod command went in as commit 64e7c440 The traceon/traceoff commands went in as commit 23b4ff3aSigned-off-by: NChase Douglas <chase.douglas@canonical.com> LKML-Reference: <1272045759-32018-1-git-send-email-chase.douglas@canonical.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 25 4月, 2010 1 次提交
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由 KAMEZAWA Hiroyuki 提交于
Writing to cgroup.procs is not supported now. Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: NLi Zefan <lizf@cn.fujitsu.com> Cc: Ben Blum <bblum@andrew.cmu.edu> Cc: Paul Menage <menage@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 23 4月, 2010 3 次提交
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由 Roman Fietze 提交于
According to libata-core correctly around line 6572: /* parse id */ p = strchr(id, '.'); ... the optional device is separated from the port in the libata.force ID by a point or dot instead of by a colon. Fix documentation to reflect this. Signed-off-by: NRoman Fietze <roman.fietze@telemotive.de> Signed-off-by: NJeff Garzik <jgarzik@redhat.com>
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由 Randy Dunlap 提交于
Update git home page info. Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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由 Stefan Richter 提交于
It is a hard requirement to include the upstream commit ID in the changelog of a -stable submission, not just a courtesy to the stable team. This concerns only mail submission though, which is no longer the only way into stable. (Also, fix a double "the".) Signed-off-by: NStefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: NRandy Dunlap <rdunlap@xenotime.net> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 22 4月, 2010 1 次提交
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由 Frederic Weisbecker 提交于
The ftrace_dump_on_oops kernel parameter, sysctl and sysrq let one dump every cpu buffers when an oops or panic happens. It's nice when you have few cpus but it may take ages if have many, plus you miss the real origin of the problem in all the cpu traces. Sometimes, all you need is to dump the cpu buffer that triggered the opps, most of the time it is our main interest. This patch modifies ftrace_dump_on_oops to handle this choice. The ftrace_dump_on_oops kernel parameter, when it comes alone, has the same behaviour than before. But ftrace_dump_on_oops=orig_cpu will only dump the buffer of the cpu that oops'ed. Similarly, sysctl kernel.ftrace_dump_on_oops=1 and echo 1 > /proc/sys/kernel/ftrace_dump_on_oops keep their previous behaviour. But setting 2 jumps into cpu origin dump mode. v2: Fix double setup v3: Fix spelling issues reported by Randy Dunlap v4: Also update __ftrace_dump in the selftests Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NSteven Rostedt <rostedt@goodmis.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
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- 15 4月, 2010 1 次提交
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由 Masami Hiramatsu 提交于
Support basic types of integer (u8, u16, u32, u64, s8, s16, s32, s64) in kprobe tracer. With this patch, users can specify above basic types on each arguments after ':'. If omitted, the argument type is set as unsigned long (u32 or u64, arch-dependent). e.g. echo 'p account_system_time+0 hardirq_offset=%si:s32' > kprobe_events adds a probe recording hardirq_offset in signed-32bits value on the entry of account_system_time. Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100412171708.3790.18599.stgit@localhost6.localdomain6> Signed-off-by: NMasami Hiramatsu <mhiramat@redhat.com> Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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- 14 4月, 2010 2 次提交
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由 viresh kumar 提交于
Reviewed-by: NLinus Walleij <linux.walleij@stericsson.com> Signed-off-by: NViresh Kumar <viresh.kumar@st.com> Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
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由 Paul E. McKenney 提交于
Update examples and lists of APIs to include these new primitives. Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com Cc: eric.dumazet@gmail.com LKML-Reference: <1270852752-25278-3-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 08 4月, 2010 1 次提交
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由 Patrick Loschmidt 提交于
The current documentation for hardware time stamping does not correctly specify the available kernel functions since the implementation was changed later on. Signed-off-by: NPatrick Loschmidt <Patrick.Loschmidt@oeaw.ac.at> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 07 4月, 2010 2 次提交
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由 Justin P. Mattock 提交于
Rename imacfb.txt to efifb.txt since imacfb was moved to efifb,and change imacfb to efifb. Signed-off-by: NJustin P. Mattock <justinmattock@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Joerg Roedel 提交于
Support for the share and fullflush parameters was removed. Remove the documentation about them too. Signed-off-by: NJoerg Roedel <joerg.roedel@amd.com>
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- 06 4月, 2010 1 次提交
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由 James Hogan 提交于
In the watchdog-test program and watchdog-api.txt, pass the values to the WDIOC_SETOPTIONS ioctl as a pointer to an integer containing the values intead of directly in the third ioctl argument. The actual watchdog drivers in drivers/watchdog don't read the options directly from the argument but use get_user and copy_from_user. Signed-off-by: NJames Hogan <james.hogan@imgtec.com> Signed-off-by: NWim Van Sebroeck <wim@iguana.be> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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- 05 4月, 2010 1 次提交
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由 Sripathi Kodi 提交于
This patch adds documentation for new 9P options introduced in 2.6.34. Signed-off-by: NSripathi Kodi <sripathik@in.ibm.com> Signed-off-by: NEric Van Hensbergen <ericvh@gmail.com>
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- 04 4月, 2010 1 次提交
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由 Giel van Schijndel 提交于
Don't terminate the watchdog daemon when fsync() fails because no watchdog driver actually implements the fsync() syscall. Signed-off-by: NGiel van Schijndel <me@mortis.eu> Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
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- 03 4月, 2010 1 次提交
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由 Li Zefan 提交于
USER_SCHED has been removed, so update the documentation accordingly. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: NSerge E. Hallyn <serue@us.ibm.com> LKML-Reference: <4BA9A07E.8070508@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 02 4月, 2010 2 次提交
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由 Giuseppe CAVALLARO 提交于
Add Documentation/networking/stmmac.txt for the stmmac network driver. Signed-off-by: NGiuseppe Cavallaro <peppe.cavallaro@st.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Takashi Iwai 提交于
Signed-off-by: NTakashi Iwai <tiwai@suse.de>
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- 30 3月, 2010 2 次提交
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由 Tejun Heo 提交于
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: NTejun Heo <tj@kernel.org> Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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由 Cheng Renquan 提交于
New documentation should have an entry in the 00-INDEX. Correct git urls. Signed-off-by: NCheng Renquan <crquan@gmail.com> Signed-off-by: NSage Weil <sage@newdream.net>
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- 27 3月, 2010 1 次提交
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由 Timur Tabi 提交于
Define a binding for embedding a QE firmware blob into the device tree. Also define a new property for the QE node that links to a firmware node. Signed-off-by: NTimur Tabi <timur@freescale.com> Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
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- 25 3月, 2010 5 次提交
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由 David Howells 提交于
Document the circular buffering capabilities available in Linux. Signed-off-by: NDavid Howells <dhowells@redhat.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: NRandy Dunlap <rdunlap@xenotime.net> Reviewed-by: NStefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 KOSAKI Motohiro 提交于
commit 3f226aa1 (mempolicy: support mpol=local tmpfs mount option) added new mpol=local mount option. but it didn't add a documentation. This patch does it. Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Ravikiran Thirumalai <kiran@scalex86.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: NLee Schermerhorn <lee.schermerhorn@hp.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: <stable@kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 FUJITA Tomonori 提交于
This patch renames PCI/PCI-DMA-mapping.txt to DMA-API-HOWTO.txt. The commit 51e7364e "Documentation: rename PCI-DMA-mapping.txt to DMA-API-HOWTO.txt" was supposed to do this but it didn't. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Greg Thelen 提交于
Update memory.txt to be more consistent: s/swapiness/swappiness/ Signed-off-by: NGreg Thelen <gthelen@google.com> Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Russell King 提交于
cpu_relax() is documented in volatile-considered-harmful.txt to be a memory barrier. However, everyone with the exception of Blackfin and possibly ia64 defines cpu_relax() to be a compiler barrier. Make the documentation reflect the general concensus. Linus sayeth: : I don't think it was ever the intention that it would be seen as anything : but a compiler barrier, although it is obviously implied that it might : well perform some per-architecture actions that have "memory barrier-like" : semantics. : : After all, the whole and only point of the "cpu_relax()" thing is to tell : the CPU that we're busy-looping on some event. : : And that "event" might be (and often is) about reading the same memory : location over and over until it changes to what we want it to be. So it's : quite possible that on various architectures the "cpu_relax()" could be : about making sure that such a tight loop on loads doesn't starve cache : transactions, for example - and as such look a bit like a memory barrier : from a CPU standpoint. : : But it's not meant to have any kind of architectural memory ordering : semantics as far as the kernel is concerned - those must come from other : sources. Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk> Cc: <linux-arch@vger.kernel.org> Acked-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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