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2019-04-03locking/rwsem: Remove arch specific rwsem filesWaiman Long
As the generic rwsem-xadd code is using the appropriate acquire and release versions of the atomic operations, the arch specific rwsem.h files will not be that much faster than the generic code as long as the atomic functions are properly implemented. So we can remove those arch specific rwsem.h and stop building asm/rwsem.h to reduce maintenance effort. Currently, only x86, alpha and ia64 have implemented architecture specific fast paths. I don't have access to alpha and ia64 systems for testing, but they are legacy systems that are not likely to be updated to the latest kernel anyway. By using a rwsem microbenchmark, the total locking rates on a 4-socket 56-core 112-thread x86-64 system before and after the patch were as follows (mixed means equal # of read and write locks): Before Patch After Patch # of Threads wlock rlock mixed wlock rlock mixed ------------ ----- ----- ----- ----- ----- ----- 1 29,201 30,143 29,458 28,615 30,172 29,201 2 6,807 13,299 1,171 7,725 15,025 1,804 4 6,504 12,755 1,520 7,127 14,286 1,345 8 6,762 13,412 764 6,826 13,652 726 16 6,693 15,408 662 6,599 15,938 626 32 6,145 15,286 496 5,549 15,487 511 64 5,812 15,495 60 5,858 15,572 60 There were some run-to-run variations for the multi-thread tests. For x86-64, using the generic C code fast path seems to be a little bit faster than the assembly version with low lock contention. Looking at the assembly version of the fast paths, there are assembly to/from C code wrappers that save and restore all the callee-clobbered registers (7 registers on x86-64). The assembly generated from the generic C code doesn't need to do that. That may explain the slight performance gain here. The generic asm rwsem.h can also be merged into kernel/locking/rwsem.h with no code change as no other code other than those under kernel/locking needs to access the internal rwsem macros and functions. Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Will Deacon <will.deacon@arm.com> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-c6x-dev@linux-c6x.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Cc: linuxppc-dev@lists.ozlabs.org Cc: nios2-dev@lists.rocketboards.org Cc: openrisc@lists.librecores.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190322143008.21313-2-longman@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07Merge branch 'linus' into locking/core, to resolve conflictsIngo Molnar
Conflicts: include/linux/compiler-clang.h include/linux/compiler-gcc.h include/linux/compiler-intel.h include/uapi/linux/stddef.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-10locking/arch, ia64: Add __down_read_killable()Kirill Tkhai
Similar to __down_write_killable(), and read killable primitive. Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: arnd@arndb.de Cc: avagin@virtuozzo.com Cc: davem@davemloft.net Cc: fenghua.yu@intel.com Cc: gorcunov@virtuozzo.com Cc: heiko.carstens@de.ibm.com Cc: hpa@zytor.com Cc: ink@jurassic.park.msu.ru Cc: mattst88@gmail.com Cc: rientjes@google.com Cc: rth@twiddle.net Cc: schwidefsky@de.ibm.com Cc: tony.luck@intel.com Cc: viro@zeniv.linux.org.uk Link: http://lkml.kernel.org/r/150670116749.23930.14976888440968191759.stgit@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-08locking/rwsem: Remove rwsem_atomic_add() and rwsem_atomic_update()Jason Low
The rwsem-xadd count has been converted to an atomic variable and the rwsem code now directly uses atomic_long_add() and atomic_long_add_return(), so we can remove the arch implementations of rwsem_atomic_add() and rwsem_atomic_update(). Signed-off-by: Jason Low <jason.low2@hpe.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Lameter <cl@linux.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Turner <mattst88@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Terry Rudd <terry.rudd@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Waiman Long <Waiman.Long@hpe.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-08locking/rwsem: Convert sem->count to 'atomic_long_t'Jason Low
Convert the rwsem count variable to an atomic_long_t since we use it as an atomic variable. This also allows us to remove the rwsem_atomic_{add,update}() "abstraction" which would now be an unnecesary level of indirection. In follow up patches, we also remove the rwsem_atomic_{add,update}() definitions across the various architectures. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Jason Low <jason.low2@hpe.com> [ Build warning fixes on various architectures. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jason Low <jason.low2@hp.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Terry Rudd <terry.rudd@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Waiman Long <Waiman.Long@hpe.com> Link: http://lkml.kernel.org/r/1465017963-4839-2-git-send-email-jason.low2@hpe.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-13locking/rwsem, ia64: Provide __down_write_killable()Michal Hocko
Introduce ___down_write() for the fast path and reuse it for __down_write() resp. __down_write_killable() each using the respective generic slow path (rwsem_down_write_failed() resp. rwsem_down_write_failed_killable()). Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Zankel <chris@zankel.net> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Signed-off-by: Jason Low <jason.low2@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: linux-alpha@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-ia64@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-sh@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: sparclinux@vger.kernel.org Link: http://lkml.kernel.org/r/1460041951-22347-9-git-send-email-mhocko@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-17fix Christoph's email addressesChristoph Lameter
There are various email addresses for me throughout the kernel. Use the one that will always be valid. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-27rwsem: Move duplicate function prototypes to linux/rwsem.hThomas Gleixner
All architecture specific rwsem headers carry the same function prototypes. Just x86 adds asmregparm, which is an empty define on all other architectures. S390 has a stale rwsem_downgrade_write() prototype. Remove the duplicates and add the prototypes to linux/rwsem.h Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Richard Henderson <rth@twiddle.net> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.970840140@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27rwsem: Unify the duplicate rwsem_is_locked() inlinesThomas Gleixner
Instead of having the same implementation in each architecture, move it to linux/rwsem.h and remove the duplicates. It's unlikely that an arch will ever implement something different, but we can deal with that when it happens. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Matt Turner <mattst88@gmail.com> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.876773757@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27rwsem: Move duplicate init macros and functions to linux/rwsem.hThomas Gleixner
The rwsem initializers and related macros and functions are mostly the same. Some of them lack the lockdep initializer, but having it in place does not matter for architectures which do not support lockdep. powerpc, sparc, x86: No functional change sh, s390: Removes the duplicate init_rwsem (inline and #define) alpha, ia64, xtensa: Use the lockdep capable init function in lib/rwsem.c which is just uninlining the init function for the LOCKDEP=n case Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Matt Turner <mattst88@gmail.com> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.771812729@linutronix.de>
2011-01-27rwsem: Move duplicate struct rwsem declaration to linux/rwsem.hThomas Gleixner
The difference between these declarations is the data type of the count member and the lack of lockdep in some architectures/ long is equivivalent to signed long and the #ifdef guarded dep_map member does not hurt anyone. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Matt Turner <mattst88@gmail.com> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.679641914@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-01-27rwsem: Cleanup includesThomas Gleixner
All rwsem implementations include the same headers. Include them from include/linux/rwsem.h Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: David Howells <dhowells@redhat.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Matt Turner <mattst88@gmail.com> Acked-by: Tony Luck <tony.luck@intel.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Acked-by: David Miller <davem@davemloft.net> Cc: Chris Zankel <chris@zankel.net> LKML-Reference: <20110126195833.483520950@linutronix.de>
2010-08-12[IA64] Fix rwsem: RWSEM_WAITING_BIAS must not be unsigned.Tony Luck
Some nice improvements were made to rwsem in commit: 424acaaeb3a3932d64a9b4bd59df6cf72c22d8f3 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>
2009-12-14[IA64] Replace old style lock initializerThomas Gleixner
SPIN_LOCK_UNLOCKED is deprecated. Use __SPIN_LOCK_UNLOCKED instead. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-ia64@vger.kernel.org Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-08-01[IA64] Move include/asm-ia64 to arch/ia64/include/asmTony Luck
After moving the the include files there were a few clean-ups: 1) Some files used #include <asm-ia64/xyz.h>, changed to <asm/xyz.h> 2) Some comments alerted maintainers to look at various header files to make matching updates if certain code were to be changed. Updated these comments to use the new include paths. 3) Some header files mentioned their own names in initial comments. Just deleted these self references. Signed-off-by: Tony Luck <tony.luck@intel.com>