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2017-12-15percpu: percpu_counter_initialized can be booleanguoyayun1-3/+3
This patch makes percpu_counter_initialized return bool due to this particular function only using either one or zero as its return value. No functional change. Signed-off-by: guoyayun <guoyayun@cmss.chinamobile.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
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>
2017-06-20percpu_counter: Rename __percpu_counter_add to percpu_counter_add_batchNikolay Borisov1-3/+4
Currently, percpu_counter_add is a wrapper around __percpu_counter_add which is preempt safe due to explicit calls to preempt_disable. Given how __ prefix is used in percpu related interfaces, the naming unfortunately creates the false sense that __percpu_counter_add is less safe than percpu_counter_add. In terms of context-safety, they're equivalent. The only difference is that the __ version takes a batch parameter. Make this a bit more explicit by just renaming __percpu_counter_add to percpu_counter_add_batch. This patch doesn't cause any functional changes. tj: Minor updates to patch description for clarity. Cosmetic indentation updates. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: David Sterba <dsterba@suse.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Jan Kara <jack@suse.com> Cc: Jens Axboe <axboe@fb.com> Cc: linux-mm@kvack.org Cc: "David S. Miller" <davem@davemloft.net>
2015-05-29percpu_counter: batch size aware __percpu_counter_compare()Dave Chinner1-1/+12
XFS uses non-stanard batch sizes for avoiding frequent global counter updates on it's allocated inode counters, as they increment or decrement in batches of 64 inodes. Hence the standard percpu counter batch of 32 means that the counter is effectively a global counter. Currently Xfs uses a batch size of 128 so that it doesn't take the global lock on every single modification. However, Xfs also needs to compare accurately against zero, which means we need to use percpu_counter_compare(), and that has a hard-coded batch size of 32, and hence will spuriously fail to detect when it is supposed to use precise comparisons and hence the accounting goes wrong. Add __percpu_counter_compare() to take a custom batch size so we can use it sanely in XFS and factor percpu_counter_compare() to use it. Signed-off-by: Dave Chinner <dchinner@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-09-08percpu_counter: add @gfp to percpu_counter_init()Tejun Heo1-4/+6
Percpu allocator now supports allocation mask. Add @gfp to percpu_counter_init() so that !GFP_KERNEL allocation masks can be used with percpu_counters too. We could have left percpu_counter_init() alone and added percpu_counter_init_gfp(); however, the number of users isn't that high and introducing _gfp variants to all percpu data structures would be quite ugly, so let's just do the conversion. This is the one with the most users. Other percpu data structures are a lot easier to convert. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Acked-by: "David S. Miller" <davem@davemloft.net> Cc: x86@kernel.org Cc: Jens Axboe <axboe@kernel.dk> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org>
2013-02-05percpu_counter.h: comment code for better readabilityJesper Dangaard Brouer1-1/+1
Help people reading the percpu_counter code, to notice the ifdef else statement that seperates CONFIG_SMP. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-09-13locking, percpu_counter: Annotate ::lock as rawThomas Gleixner1-1/+1
The percpu_counter::lock can be taken in atomic context and therefore cannot be preempted on -rt - annotate it. In mainline this change documents the low level nature of the lock - otherwise there's no functional difference. Lockdep and Sparse checking will work as usual. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-05-25percpu_counter: change return value and add commentsShaohua Li1-1/+5
The percpu_counter_*_positive() API in UP case doesn't check if return value is positive. Add comments to explain why we don't. Also if count < 0, returns 0 instead of 1 for *read_positive(). [akpm@linux-foundation.org: tweak comment] Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27ext4: fix kernel oops if the journal superblock has a non-zero j_errnoTheodore Ts'o1-0/+10
Commit 84061e0 fixed an accounting bug only to introduce the possibility of a kernel OOPS if the journal has a non-zero j_errno field indicating that the file system had detected a fs inconsistency. After the journal replay, if the journal superblock indicates that the file system has an error, this indication is transfered to the file system and then ext4_commit_super() is called to write this to the disk. But since the percpu counters are now initialized after the journal replay, the call to ext4_commit_super() will cause a kernel oops since it needs to use the percpu counters the ext4 superblock structure. The fix is to skip setting the ext4 free block and free inode fields if the percpu counter has not been set. Thanks to Ken Sumrall for reporting and analyzing the root causes of this bug. Addresses-Google-Bug: #3054080 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2010-08-09tmpfs: add accurate compare function to percpu_counter libraryTim Chen1-0/+11
Add percpu_counter_compare that allows for a quick but accurate comparison of percpu_counter with a given value. A rough count is provided by the count field in percpu_counter structure, without accounting for the other values stored in individual cpu counters. The actual count is a sum of count and the cpu counters. However, count field is never different from the actual value by a factor of batch*num_online_cpu. We do not need to get actual count for comparison if count is different from the given value by this factor and allows for quick comparison without summing up all the per cpu counters. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-03Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpuLinus Torvalds1-1/+1
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: add __percpu sparse annotations to what's left percpu: add __percpu sparse annotations to fs percpu: add __percpu sparse annotations to core kernel subsystems local_t: Remove leftover local.h this_cpu: Remove pageset_notifier this_cpu: Page allocator conversion percpu, x86: Generic inc / dec percpu instructions local_t: Move local.h include to ringbuffer.c and ring_buffer_benchmark.c module: Use this_cpu_xx to dynamically allocate counters local_t: Remove cpu_local_xx macros percpu: refactor the code in pcpu_[de]populate_chunk() percpu: remove compile warnings caused by __verify_pcpu_ptr() percpu: make accessors check for percpu pointer in sparse percpu: add __percpu for sparse. percpu: make access macros universal percpu: remove per_cpu__ prefix.
2010-02-17percpu: add __percpu sparse annotations to core kernel subsystemsTejun Heo1-1/+1
Add __percpu sparse annotations to core subsystems. These annotations are to make sparse consider percpu variables to be in a different address space and warn if accessed without going through percpu accessors. This patch doesn't affect normal builds. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-mm@kvack.org Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Biederman <ebiederm@xmission.com>
2010-02-08percpu_counter: Make __percpu_counter_add an inline function on UPAnton Blanchard1-3/+6
Even though batch isn't used on UP, we may want to pass one in to keep the SMP and UP code paths similar. Convert __percpu_counter_add to an inline function so we wont get variable unused warnings if we do. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-06Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tipLinus Torvalds1-4/+10
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: fix rcutorture bug rcu: eliminate synchronize_rcu_xxx macro rcu: make treercu safe for suspend and resume rcu: fix rcutree grace-period-latency bug on small systems futex: catch certain assymetric (get|put)_futex_key calls futex: make futex_(get|put)_key() calls symmetric locking, percpu counters: introduce separate lock classes swiotlb: clean up EXPORT_SYMBOL usage swiotlb: remove unnecessary declaration swiotlb: replace architecture-specific swiotlb.h with linux/swiotlb.h swiotlb: add support for systems with highmem swiotlb: store phys address in io_tlb_orig_addr array swiotlb: add hwdev to swiotlb_phys_to_bus() / swiotlb_sg_to_bus()
2009-01-06percpu_counter: FBC_BATCH should be a variableEric Dumazet1-6/+2
For NR_CPUS >= 16 values, FBC_BATCH is 2*NR_CPUS Considering more and more distros are using high NR_CPUS values, it makes sense to use a more sensible value for FBC_BATCH, and get rid of NR_CPUS. A sensible value is 2*num_online_cpus(), with a minimum value of 32 (This minimum value helps branch prediction in __percpu_counter_add()) We already have a hotcpu notifier, so we can adjust FBC_BATCH dynamically. We rename FBC_BATCH to percpu_counter_batch since its not a constant anymore. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-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>
2008-12-29locking, percpu counters: introduce separate lock classesPeter Zijlstra1-4/+10
Impact: fix lockdep false positives Classify percpu_counter instances similar to regular lock objects -- that is, per instantiation site. The networking code has increased its use of percpu_counters, which leads to false positives if they are treated as a single class. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-12-10revert "percpu_counter: new function percpu_counter_sum_and_set"Andrew Morton1-9/+3
Revert commit e8ced39d5e8911c662d4d69a342b9d053eaaac4e Author: Mingming Cao <cmm@us.ibm.com> Date: Fri Jul 11 19:27:31 2008 -0400 percpu_counter: new function percpu_counter_sum_and_set As described in revert "percpu counter: clean up percpu_counter_sum_and_set()" the new percpu_counter_sum_and_set() is racy against updates to the cpu-local accumulators on other CPUs. Revert that change. This means that ext4 will be slow again. But correct. Reported-by: Eric Dumazet <dada1@cosmosbay.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mingming Cao <cmm@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Cc: <stable@kernel.org> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-10revert "percpu counter: clean up percpu_counter_sum_and_set()"Andrew Morton1-3/+9
Revert commit 1f7c14c62ce63805f9574664a6c6de3633d4a354 Author: Mingming Cao <cmm@us.ibm.com> Date: Thu Oct 9 12:50:59 2008 -0400 percpu counter: clean up percpu_counter_sum_and_set() Before this patch we had the following: percpu_counter_sum(): return the percpu_counter's value percpu_counter_sum_and_set(): return the percpu_counter's value, copying that value into the central value and zeroing the per-cpu counters before returning. After this patch, percpu_counter_sum_and_set() has gone, and percpu_counter_sum() gets the old percpu_counter_sum_and_set() functionality. Problem is, as Eric points out, the old percpu_counter_sum_and_set() functionality was racy and wrong. It zeroes out counters on "other" cpus, without holding any locks which will prevent races agaist updates from those other CPUS. This patch reverts 1f7c14c62ce63805f9574664a6c6de3633d4a354. This means that percpu_counter_sum_and_set() still has the race, but percpu_counter_sum() does not. Note that this is not a simple revert - ext4 has since started using percpu_counter_sum() for its dirty_blocks counter as well. Note that this revert patch changes percpu_counter_sum() semantics. Before the patch, a call to percpu_counter_sum() will bring the counter's central counter mostly up-to-date, so a following percpu_counter_read() will return a close value. After this patch, a call to percpu_counter_sum() will leave the counter's central accumulator unaltered, so a subsequent call to percpu_counter_read() can now return a significantly inaccurate result. If there is any code in the tree which was introduced after e8ced39d5e8911c662d4d69a342b9d053eaaac4e was merged, and which depends upon the new percpu_counter_sum() semantics, that code will break. Reported-by: Eric Dumazet <dada1@cosmosbay.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mingming Cao <cmm@us.ibm.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-09percpu counter: clean up percpu_counter_sum_and_set()Mingming Cao1-9/+3
percpu_counter_sum_and_set() and percpu_counter_sum() is the same except the former updates the global counter after accounting. Since we are taking the fbc->lock to calculate the precise value of the counter in percpu_counter_sum() anyway, it should simply set fbc->count too, as the percpu_counter_sum_and_set() does. This patch merges these two interfaces into one. Signed-off-by: Mingming Cao <cmm@us.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-07-11percpu_counter: new function percpu_counter_sum_and_setMingming Cao1-3/+9
Delayed allocation need to check free blocks at every write time. percpu_counter_read_positive() is not quit accurate. delayed allocation need a more accurate accounting, but using percpu_counter_sum_positive() is frequently is quite expensive. This patch added a new function to update center counter when sum per-cpu counter, to increase the accurate rate for next percpu_counter_read() and require less calling expensive percpu_counter_sum(). Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2007-10-17lib: percpu_counter_init_irqPeter Zijlstra1-0/+3
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>
2007-10-17lib: percpu_counter_init error handlingPeter Zijlstra1-2/+3
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>
2007-10-17lib: percpu_count_sum()Peter Zijlstra1-1/+17
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>
2007-10-17lib: percpu_counter_sum_positivePeter Zijlstra1-2/+2
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>
2007-10-17lib: percpu_counter_setPeter Zijlstra1-0/+6
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>
2007-10-17lib: make percpu_counter_add take s64Peter Zijlstra1-3/+3
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>
2007-10-17lib: percpu_counter variable batchPeter Zijlstra1-1/+9
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>
2007-10-17lib: percpu_counter_subPeter Zijlstra1-0/+5
Hugh spotted that some code does: percpu_counter_add(&counter, -unsignedlong) which, when the amount argument is of type s32, sort-of works thanks to two's-complement. However when we'd change the type to s64 this breaks on 32bit machines, because the promotion rules zero extend the unsigned number. Provide percpu_counter_sub() to hide the s64 cast. That is: percpu_counter_sub(&counter, foo) is equal to: percpu_counter_add(&counter, -(s64)foo); Signed-off-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>
2007-10-17lib: percpu_counter_addPeter Zijlstra1-4/+4
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>
2007-07-16percpu_counters(): use cpu notifiersAndrew Morton1-12/+6
per-cpu counters presently must iterate over all possible CPUs in the exhaustive percpu_counter_sum(). But it can be much better to only iterate over the presently-online CPUs. To do this, we must arrange for an offlined CPU's count to be spilled into the counter's central count. We can do this for all percpu_counters in the machine by linking them into a single global list and walking that list at CPU_DEAD time. (I hope. Might have race windows in which the percpu_counter_sum() count is inaccurate?) Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: 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>
2006-06-23[PATCH] percpu counter data type changes to suppport more than 2**31 ext3 free blocks counterMingming Cao1-18/+20
The percpu counter data type are changed in this set of patches to support more users like ext3 who need more than 32 bit to store the free blocks total in the filesystem. - Generic perpcu counters data type changes. The size of the global counter and local counter were explictly specified using s64 and s32. The global counter is changed from long to s64, while the local counter is changed from long to s32, so we could avoid doing 64 bit update in most cases. - Users of the percpu counters are updated to make use of the new percpu_counter_init() routine now taking an additional parameter to allow users to pass the initial value of the global counter. Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-26Don't include linux/config.h from anywhere else in include/David Woodhouse1-1/+0
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-03-08[PATCH] percpu_counter_sum()Andrew Morton1-0/+6
Implement percpu_counter_sum(). This is a more accurate but slower version of percpu_counter_read_positive(). We need this for Alex's speedup-ext3_statfs patch and for the nr_file accounting fix. Otherwise these things would be too inaccurate on large CPU counts. Cc: Ravikiran G Thirumalai <kiran@scalex86.org> Cc: Alex Tomas <alex@clusterfs.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16Linux-2.6.12-rc2Linus Torvalds1-0/+107
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!