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path: root/include/linux/percpu-defs.h
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2015-07-14percpu: update incorrect comment for this_cpu_*() operationsTejun Heo
this_cpu_*() ops have been protected against both preemption and interrupts for quite a while now. We apparently forgot to update the comment. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org>
2014-12-13percpu: remove __get_cpu_var and __raw_get_cpu_var macrosChristoph Lameter
No user is left in the kernel source tree. Therefore we can drop the definitions. This is the final merge of the transition away from __get_cpu_var. After this patch the kernel will not build if anyone uses __get_cpu_var. Signed-off-by: Christoph Lameter <cl@linux.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>
2014-08-26percpu: Remove __this_cpu_ptrChristoph Lameter
The __this_cpu_ptr macro is no longer in use so drop it. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-04Merge branch 'for-3.17' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull percpu updates from Tejun Heo: - Major reorganization of percpu header files which I think makes things a lot more readable and logical than before. - percpu-refcount is updated so that it requires explicit destruction and can be reinitialized if necessary. This was pulled into the block tree to replace the custom percpu refcnting implemented in blk-mq. - In the process, percpu and percpu-refcount got cleaned up a bit * 'for-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (21 commits) percpu-refcount: implement percpu_ref_reinit() and percpu_ref_is_zero() percpu-refcount: require percpu_ref to be exited explicitly percpu-refcount: use unsigned long for pcpu_count pointer percpu-refcount: add helpers for ->percpu_count accesses percpu-refcount: one bit is enough for REF_STATUS percpu-refcount, aio: use percpu_ref_cancel_init() in ioctx_alloc() workqueue: stronger test in process_one_work() workqueue: clear POOL_DISASSOCIATED in rebind_workers() percpu: Use ALIGN macro instead of hand coding alignment calculation percpu: invoke __verify_pcpu_ptr() from the generic part of accessors and operations percpu: preffity percpu header files percpu: use raw_cpu_*() to define __this_cpu_*() percpu: reorder macros in percpu header files percpu: move {raw|this}_cpu_*() definitions to include/linux/percpu-defs.h percpu: move generic {raw|this}_cpu_*_N() definitions to include/asm-generic/percpu.h percpu: only allow sized arch overrides for {raw|this}_cpu_*() ops percpu: reorganize include/linux/percpu-defs.h percpu: move accessors from include/linux/percpu.h to percpu-defs.h percpu: include/asm-generic/percpu.h should contain only arch-overridable parts percpu: introduce arch_raw_cpu_ptr() ...
2014-07-01core: fix typo in percpu read_mostly sectionZhengyu He
This fixes a typo that named the read_mostly section of percpu as readmostly. It works fine with SMP because the linker script specifies .data..percpu..readmostly. However, UP kernel builds don't have percpu sections defined and the non-percpu version of the section is called data..read_mostly, so .data..readmostly will float around and may break things unexpectedly. Looking at the original change that introduced data..percpu..readmostly (commit c957ef2c59e952803766ddc22e89981ab534606f), it looks like this was the original intention. Tested: Built UP kernel and confirmed the sections got merged. - Before the patch: $ objdump -h vmlinux.o | grep '\.data\.\.read.*mostly' 38 .data..read_mostly 00004418 0000000000000000 0000000000000000 00431ac0 2**6 50 .data..readmostly 00000014 0000000000000000 0000000000000000 00444000 2**3 - After the patch: $ objdump -h vmlinux.o | grep '\.data\.\.read.*mostly' 38 .data..read_mostly 00004438 0000000000000000 0000000000000000 00431ac0 2**6 Signed-off-by: Zhengyu He <hzy@google.com> Signed-off-by: Filipe Brandenburger <filbranden@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-06-17percpu: invoke __verify_pcpu_ptr() from the generic part of accessors and ↵Tejun Heo
operations __verify_pcpu_ptr() is used to verify that a specified parameter is actually an percpu pointer by percpu accessor and operation implementations. Currently, where it's called isn't clearly defined and we just ensure that it's invoked at least once for all accessors and operations. The lack of clarity on when it should be called isn't nice and given that this is a completely generic issue, there's no reason to make archs worry about it. This patch updates __verify_pcpu_ptr() invocations such that it's always invoked from the final generic wrapper once per access or operation. As this is already the case for {raw|this}_cpu_*() definitions through __pcpu_size_*(), only the {raw|per|this}_cpu_ptr() accessors need to be updated. This change makes it unnecessary for archs to worry about __verify_pcpu_ptr(). x86's arch_raw_cpu_ptr() is updated accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com>
2014-06-17percpu: preffity percpu header filesTejun Heo
percpu macros are difficult to read. It's partly because they're fairly complex but also because they simply lack visual and conventional consistency to an unusual degree. The preceding patches tried to organize macro definitions consistently by their roles. This patch makes the following cosmetic changes to improve overall readability. * Use consistent convention for multi-line macro definitions - "do {" or "({" are now put on their own lines and the line continuing '\' are all put on the same column. * Temp variables used inside macro are consistently given "__" prefix. * When a macro argument is passed to another macro or a function, putting extra parenthses around it doesn't help anything. Don't put them. * _this_cpu_generic_*() are renamed to this_cpu_generic_*() so that they're consistent with raw_cpu_generic_*(). * Reorganize raw_cpu_*() and this_cpu_*() definitions so that trivial wrappers are collected in one place after actual operation definitions. * Other misc cleanups including reorganizing comments. All changes in this patch are cosmetic and cause no functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2014-06-17percpu: use raw_cpu_*() to define __this_cpu_*()Tejun Heo
__this_cpu_*() operations are the same as raw_cpu_*() operations except for the added __this_cpu_preempt_check(). Curiously, these were defined using __pcu_size_call_*() instead of being layered on top of raw_cpu_*(). Let's layer them so that __this_cpu_*() are defined in terms of raw_cpu_*(). It's simpler and less error-prone this way. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2014-06-17percpu: reorder macros in percpu header filesTejun Heo
* In include/asm-generic/percpu.h, collect {raw|_this}_cpu_generic*() macros into one place. They were dispersed through {raw|this}_cpu_*_N() definitions and the visiual inconsistency was making following the code unnecessarily difficult. * In include/linux/percpu-defs.h, move __verify_pcpu_ptr() later in the file so that it's right above accessor definitions where it's actually used. This is pure reorganization. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2014-06-17percpu: move {raw|this}_cpu_*() definitions to include/linux/percpu-defs.hTejun Heo
We're in the process of moving all percpu accessors and operations to include/linux/percpu-defs.h so that they're available to arch headers without having to include full include/linux/percpu.h which may cause cyclic inclusion dependency. This patch moves {raw|this}_cpu_*() definitions from include/linux/percpu.h to include/linux/percpu-defs.h. The code is moved mostly verbatim; however, raw_cpu_*() are placed above this_cpu_*() which is more conventional as the raw operations may be used to defined other variants. This is pure reorganization. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2014-06-17percpu: reorganize include/linux/percpu-defs.hTejun Heo
Reorganize for better readability. * Accessor definitions are collected into one place and SMP and UP now define them in the same order. * Definitions are layered when possible - e.g. per_cpu() is now defined in terms of this_cpu_ptr(). * Rather pointless comment dropped. * per_cpu(), __raw_get_cpu_var() and __get_cpu_var() are defined in a way which can be shared between SMP and UP and moved out of CONFIG_SMP blocks. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org>
2014-06-17percpu: move accessors from include/linux/percpu.h to percpu-defs.hTejun Heo
include/linux/percpu-defs.h is gonna host all accessors and operations so that arch headers can make use of them too without worrying about circular dependency through include/linux/percpu.h. This patch moves the following accessors from include/linux/percpu.h to include/linux/percpu-defs.h. * get/put_cpu_var() * get/put_cpu_ptr() * per_cpu_ptr() This is pure reorgniazation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2014-06-17percpu: include/asm-generic/percpu.h should contain only arch-overridable partsTejun Heo
The roles of the various percpu header files has become unclear. There are four header files involved. include/linux/percpu-defs.h include/linux/percpu.h include/asm-generic/percpu.h arch/*/include/asm/percpu.h The original intention for include/asm-generic/percpu.h is providing generic definitions for arch-overridable parts; however, it now hosts various stuff which can't be overridden by archs. Also, include/linux/percpu-defs.h was initially added to contain section and percpu variable definition macros so that arch header files can make use of them without worrying about introducing cyclic inclusion dependency by including include/linux/percpu.h; however, arch headers sometimes need to access percpu variables too and this is one of the reasons why some accessors were implemented in include/linux/asm-generic/percpu.h. Let's clear up the situation by making include/asm-generic/percpu.h contain only arch-overridable parts and moving accessors and operations into include/linux/percpu-defs. Note that this patch only moves things from include/asm-generic/percpu.h. include/linux/percpu.h will be taken care of by later patches. This patch moves the followings. * SHIFT_PERCPU_PTR() / VERIFY_PERCPU_PTR() * per_cpu() * raw_cpu_ptr() * this_cpu_ptr() * __get_cpu_var() * __raw_get_cpu_var() * __this_cpu_ptr() * PER_CPU_[SHARED_]ALIGNED_SECTION * PER_CPU_[SHARED_]ALIGNED_SECTION * PER_CPU_FIRST_SECTION This patch is pure reorganization. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Christoph Lameter <cl@linux.com>
2013-12-05percpu: fix spurious sparse warnings from DEFINE_PER_CPU()Tejun Heo
When CONFIG_DEBUG_FORCE_WEAK_PER_CPU or CONFIG_ARCH_NEEDS_WEAK_PER_CPU is set, DEFINE_PER_CPU() explodes into cryptic series of definitions to still allow using "static" for percpu variables while keeping all per-cpu symbols unique in the kernel image which is required for weak symbols. This ultimately converts the actual symbol to global whether DEFINE_PER_CPU() is prefixed with static or not. Unfortunately, the macro forgot to add explicit extern declartion of the actual symbol ending up defining global symbol without preceding declaration for static definitions which naturally don't have matching DECLARE_PER_CPU(). The only ill effect is triggering of the following warnings. fs/inode.c:74:8: warning: symbol 'nr_inodes' was not declared. Should it be static? fs/inode.c:75:8: warning: symbol 'nr_unused' was not declared. Should it be static? Fix it by adding extern declaration in the DEFINE_PER_CPU() macro. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Wanlong Gao <gaowanlong@cn.fujitsu.com> Tested-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
2013-08-23percpu: Make __verify_pcu_ptr handle per cpu pointers to arraysChristoph Lameter
__verify_pcpu_ptr() will cause a compilation failure if the type of the pointer is a pointer to a fixed array of objects. Adding zero to the pointer converts the type of pointer to that pointing to a single object of the array. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2010-10-27percpu: Remove the multi-page alignment facilityIngo Molnar
[DECLARE|DEFINE]_PER_CPU_MULTIPAGE_ALIGNED never really worked because the head percpu section was only page aligned. Now that the last user is gone (32-bit IRQ stacks), remove the generic percpu facility. Cc: Brian Gerst <brgerst@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <1288158182-1753-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-10-22Merge branch 'x86-irq-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, 32-bit: Align percpu area and irq stacks to THREAD_SIZE x86: Move alloc_desk_mask variables inside ifdef x86-32: Align IRQ stacks properly x86: Remove CONFIG_4KSTACKS x86: Always use irq stacks Fixed up trivial conflicts in include/linux/{irq.h, percpu-defs.h}
2010-10-20percpu: Introduce a read-mostly percpu APIShaohua Li
Add a new readmostly percpu section and API. This can be used to avoid dirtying data lines which are generally not written to, which is especially important for data which may be accessed by processors other than the one for which the percpu area belongs to. [ hpa: moved it *after* the page-aligned section, for obvious reasons. ] Signed-off-by: Shaohua Li <shaohua.li@intel.com> LKML-Reference: <1287544022.4571.7.camel@sli10-conroe.sh.intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2010-09-07x86, 32-bit: Align percpu area and irq stacks to THREAD_SIZEAlexander van Heukelum
The irq stacks, located in the percpu-area, need to be THREAD_SIZE aligned. Add the infrastucture to align percpu variables to larger-than-pagesize amounts within the percpu area, and use it to specify the alignment for the irq stacks. Also align the percpu area itself to THREAD_SIZE. This should make irq stacks work with 8K THREAD_SIZE. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Cc: Tejun Heo <tj@kernel.org> Cc: hch@lst.de LKML-Reference: <1283799222.15941.1393621887@webmail.messagingengine.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-01Merge branch 'for-35' of git://repo.or.cz/linux-kbuildLinus Torvalds
* 'for-35' of git://repo.or.cz/linux-kbuild: (81 commits) kbuild: Revert part of e8d400a to resolve a conflict kbuild: Fix checking of scm-identifier variable gconfig: add support to show hidden options that have prompts menuconfig: add support to show hidden options which have prompts gconfig: remove show_debug option gconfig: remove dbg_print_ptype() and dbg_print_stype() kconfig: fix zconfdump() kconfig: some small fixes add random binaries to .gitignore kbuild: Include gen_initramfs_list.sh and the file list in the .d file kconfig: recalc symbol value before showing search results .gitignore: ignore *.lzo files headerdep: perlcritic warning scripts/Makefile.lib: Align the output of LZO kbuild: Generate modules.builtin in make modules_install Revert "kbuild: specify absolute paths for cscope" kbuild: Do not unnecessarily regenerate modules.builtin headers_install: use local file handles headers_check: fix perl warnings export_report: fix perl warnings ...
2010-03-03Rename .data[.percpu][.XXX] to .data[..percpu][..XXX].Denys Vlasenko
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Michal Marek <mmarek@suse.cz>
2009-12-08percpu: remove compile warnings caused by __verify_pcpu_ptr()Tejun Heo
If percpu pointer is const, __verify_pcpu_ptr() triggers warnings like the following. drivers/net/loopback.c: In function 'loopback_get_stats': drivers/net/loopback.c:109: warning: initialization discards qualifiers from pointer target type Fix it by adding const to the verification target pointer used in __verify_pcpu_ptr(). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
2009-10-29percpu: make accessors check for percpu pointer in sparseTejun Heo
The previous patch made sparse warn about percpu variables being used directly without going through percpu accessors. This patch implements the other half - checking whether non percpu variable is passed into percpu accessors. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Al Viro <viro@zeniv.linux.org.uk>
2009-10-29percpu: add __percpu for sparse.Rusty Russell
We have to make __kernel "__attribute__((address_space(0)))" so we can cast to it. tj: * put_cpu_var() update. * Annotations added to dynamic allocator interface. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-10-29percpu: remove per_cpu__ prefix.Rusty Russell
Now that the return from alloc_percpu is compatible with the address of per-cpu vars, it makes sense to hand around the address of per-cpu variables. To make this sane, we remove the per_cpu__ prefix we used created to stop people accidentally using these vars directly. Now we have sparse, we can use that (next patch). tj: * Updated to convert stuff which were missed by or added after the original patch. * Kill per_cpu_var() macro. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
2009-10-29percpu: remove some sparse warningsTejun Heo
Make the following changes to remove some sparse warnings. * Make DEFINE_PER_CPU_SECTION() declare __pcpu_unique_* before defining it. * Annotate pcpu_extend_area_map() that it is entered with pcpu_lock held, releases it and then reacquires it. * Make percpu related macros use unique nested variable names. * While at it, add pcpu prefix to __size_call[_return]() macros as to-be-implemented sparse annotations will add percpu specific stuff to these macros. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: Rusty Russell <rusty@rustcorp.com.au>
2009-09-15Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits) powerpc64: convert to dynamic percpu allocator sparc64: use embedding percpu first chunk allocator percpu: kill lpage first chunk allocator x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA percpu: update embedding first chunk allocator to handle sparse units percpu: use group information to allocate vmap areas sparsely vmalloc: implement pcpu_get_vm_areas() vmalloc: separate out insert_vmalloc_vm() percpu: add chunk->base_addr percpu: add pcpu_unit_offsets[] percpu: introduce pcpu_alloc_info and pcpu_group_info percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward percpu: add @align to pcpu_fc_alloc_fn_t percpu: make @dyn_size mandatory for pcpu_setup_first_chunk() percpu: drop @static_size from first chunk allocators percpu: generalize first chunk allocator selection percpu: build first chunk allocators selectively percpu: rename 4k first chunk allocator to page percpu: improve boot messages percpu: fix pcpu_reclaim() locking ... Fix trivial conflict as by Tejun Heo in kernel/sched.c
2009-09-14Merge branch 'x86-percpu-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-percpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, percpu: Collect hot percpu variables into one cacheline x86, percpu: Fix DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() x86, percpu: Add 'percpu_read_stable()' interface for cacheable accesses
2009-09-04x86/i386: Put aligned stack-canary in percpu shared_aligned sectionJeremy Fitzhardinge
Pack aligned things together into a special section to minimize padding holes. Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Tejun Heo <tj@kernel.org> LKML-Reference: <4AA035C0.9070202@goop.org> [ queued up in tip:x86/asm because it depends on this commit: x86/i386: Make sure stack-protector segment base is cache aligned ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-04x86, percpu: Fix DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED()Tejun Heo
DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() put percpu variables in .page_aligned section without adding any alignment restrictions. Currently, this doesn't cause any problem because all users of the macros have explicit page alignment and page-sized but it's much safer to enforce page alignment from the macros. After all, it's what they claim to do. Add __aligned(PAGE_SIZE) to DECLARE/DEFINE_PER_CPU_PAGE_ALIGNED() and drop explicit alignment from it users. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-04Merge branch 'master' into for-nextTejun Heo
Pull linus#master to merge PER_CPU_DEF_ATTRIBUTES and alpha build fix changes. As alpha in percpu tree uses 'weak' attribute instead of inline assembly, there's no need for __used attribute. Conflicts: arch/alpha/include/asm/percpu.h arch/mn10300/kernel/vmlinux.lds.S include/linux/percpu-defs.h
2009-06-30alpha: fix percpu build breakageTejun Heo
alpha percpu access requires custom SHIFT_PERCPU_PTR() definition for modules to work around addressing range limitation. This is done via generating inline assembly using C preprocessing which forces the assembler to generate external reference. This happens behind the compiler's back and makes the compiler think that static percpu variables in modules are unused. This used to be worked around by using __unused attribute for percpu variables which prevent the compiler from omitting the variable; however, recent declare/definition attribute unification change broke this as __used can't be used for declaration. Also, in the process, PER_CPU_ATTRIBUTES definition in alpha percpu.h got broken. This patch adds PER_CPU_DEF_ATTRIBUTES which is only used for definitions and make alpha use it to add __used for percpu variables in modules. This also fixes the PER_CPU_ATTRIBUTES double definition bug. Signed-off-by: Tejun Heo <tj@kernel.org> Tested-by: maximilian attems <max@stro.at> Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Richard Henderson <rth@twiddle.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-29percpu: use __weak only in the definition of weak percpu variablesTejun Heo
__weak is necessary only for definition and might even not work in declaration. Drop it from declaration. This change was suggested by Ivan Kokshaysky. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
2009-06-24percpu: implement optional weak percpu definitionsTejun Heo
Some archs (alpha and s390) need to use weak definitions for percpu variables in modules so that the compiler generates external references for them. This patch implements weak percpu definitions which arch can enable by defining ARCH_NEEDS_WEAK_PER_CPU in arch percpu header file. This weak definition adds the following two restrictions on percpu variable definitions. 1. percpu symbols must be unique whether static or not 2. percpu variables can't be defined inside a function To ensure that these restrictions are observed in generic code, config option DEBUG_FORCE_WEAK_PER_CPU enables weak percpu definitions for all cases. This patch is inspired by Ivan Kokshaysky's alpha percpu patch. [ Impact: stricter rules for percpu variables, one more debug config option ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Howells <dhowells@redhat.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
2009-04-21PERCPU: Collect the DECLARE/DEFINE declarations togetherDavid Howells
Collect the DECLARE/DEFINE declarations together in linux/percpu-defs.h so that they're in one place, and give them descriptive comments, particularly the SHARED_ALIGNED variant. It would be nice to collect these in linux/percpu.h, but that's not possible without sorting out the severe #include recursion between the x86 arch headers and the general headers (and possibly other arches too). Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>