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2010-05-01percpu: implement kernel memory based chunk allocationTejun Heo
Implement an alternate percpu chunk management based on kernel memeory for nommu SMP architectures. Instead of mapping into vmalloc area, chunks are allocated as a contiguous kernel memory using alloc_pages(). As such, percpu allocator on nommu will have the following restrictions. * It can't fill chunks on-demand page-by-page. It has to allocate each chunk fully upfront. * It can't support sparse chunk for NUMA configurations. SMP w/o mmu is crazy enough. Let's hope no one does NUMA w/o mmu. :-P * If chunk size isn't power-of-two multiple of PAGE_SIZE, the unaligned amount will be wasted on each chunk. So, archs which use this better align chunk size. For instructions on how to use this, read the comment on top of mm/percpu-km.c. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Graff Yang <graff.yang@gmail.com> Cc: Sonic Zhang <sonic.adi@gmail.com>
2010-05-01percpu: move vmalloc based chunk management into percpu-vm.cTejun Heo
Separate out and move chunk management (creation/desctruction and [de]population) code into percpu-vm.c which is included by percpu.c and compiled together. The interface for chunk management is defined as follows. * pcpu_populate_chunk - populate the specified range of a chunk * pcpu_depopulate_chunk - depopulate the specified range of a chunk * pcpu_create_chunk - create a new chunk * pcpu_destroy_chunk - destroy a chunk, always preceded by full depop * pcpu_addr_to_page - translate address to physical address * pcpu_verify_alloc_info - check alloc_info is acceptable during init Other than wrapping vmalloc_to_page() inside pcpu_addr_to_page() and dummy pcpu_verify_alloc_info() implementation, this patch only moves code around. This separation is to allow alternate chunk management implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Graff Yang <graff.yang@gmail.com> Cc: Sonic Zhang <sonic.adi@gmail.com>
2010-05-01percpu: misc preparations for nommu supportTejun Heo
Make the following misc preparations for percpu nommu support. * Remove refernces to vmalloc in common comments as nommu percpu won't use it. * Rename chunk->vms to chunk->data and make it void *. Its use is determined by chunk management implementation. * Relocate utility functions and add __maybe_unused to functions which might not be used by different chunk management implementations. This patch doesn't cause any functional change. This is to allow alternate chunk management implementation for percpu nommu support. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Graff Yang <graff.yang@gmail.com> Cc: Sonic Zhang <sonic.adi@gmail.com>
2010-05-01percpu: reorganize chunk creation and destructionTejun Heo
Reorganize alloc/free_pcpu_chunk() such that chunk struct alloc/free live in pcpu_alloc/free_chunk() and the rest in pcpu_create/destroy_chunk(). While at it, add missing error handling for chunk->map allocation failure. This is to allow alternate chunk management implementation for percpu nommu support. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Graff Yang <graff.yang@gmail.com> Cc: Sonic Zhang <sonic.adi@gmail.com>
2010-05-01percpu: factor out pcpu_addr_in_first/reserved_chunk() and update ↵Tejun Heo
per_cpu_ptr_to_phys() Factor out pcpu_addr_in_first/reserved_chunk() from pcpu_chunk_addr_search() and use it to update per_cpu_ptr_to_phys() such that it handles first chunk differently from the rest. This patch doesn't cause any functional change and is to prepare for percpu nommu support. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: David Howells <dhowells@redhat.com> Cc: Graff Yang <graff.yang@gmail.com> Cc: Sonic Zhang <sonic.adi@gmail.com>
2010-03-29percpu, module: implement and use is_kernel/module_percpu_address()Tejun Heo
lockdep has custom code to check whether a pointer belongs to static percpu area which is somewhat broken. Implement proper is_kernel/module_percpu_address() and replace the custom code. On UP, percpu variables are regular static variables and can't be distinguished from them. Always return %false on UP. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com>
2010-02-17percpu: add __percpu sparse annotations to core kernel subsystemsTejun Heo
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>
2010-02-02Merge branch 'master' into percpuTejun Heo
2010-01-11percpu: avoid calling __pcpu_ptr_to_addr(NULL)Andrew Morton
__pcpu_ptr_to_addr() can be overridden by the architecture and might not behave well if passed a NULL pointer. So avoid calling it until we have verified that its arg is not NULL. Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-01-05Merge branch 'master' into percpuTejun Heo
Conflicts: arch/powerpc/platforms/pseries/hvCall.S include/linux/percpu.h
2009-12-08percpu: refactor the code in pcpu_[de]populate_chunk()WANG Cong
Using break statement at the end of a for loop is confusing, refactor it by replacing the for loop. Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-12-08Merge branch 'for-linus' into for-nextTejun Heo
Conflicts: mm/percpu.c
2009-11-25percpu: Fix kdump failure if booted with percpu_alloc=pageVivek Goyal
o kdump functionality reserves a per cpu area at boot time and exports the physical address of that area to user space through sys interface. This area stores some dump related information like cpu register states etc at the time of crash. o We were assuming that per cpu area always come from linearly mapped meory region and using __pa() to determine physical address. With percpu_alloc=page, per cpu area can come from vmalloc region also and __pa() breaks. o This patch implments a new function to convert per cpu address to physical address. Before the patch, crash_notes addresses looked as follows. cpu0 60fffff49800 cpu1 60fffff60800 cpu2 60fffff77800 These are bogus phsyical addresses. After the patch, address are following. cpu0 13eb44000 cpu1 13eb43000 cpu2 13eb42000 cpu3 13eb41000 These look fine. I got 4G of memory and /proc/iomem tell me following. 100000000-13fffffff : System RAM tj: * added missing asm/io.h include reported by Stephen Rothwell * repositioned per_cpu_ptr_phys() in percpu.c and added comment. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au>
2009-11-13percpu: restructure pcpu_extend_area_map() to fix bugs and improve readabilityTejun Heo
pcpu_extend_area_map() had the following two bugs. * It should return 1 if pcpu_lock was dropped and reacquired but it returned 0. This could lead to oops if free_percpu() races with area map extension. * pcpu_mem_free() was called under pcpu_lock. pcpu_mem_free() might end up calling vfree() which isn't IRQ safe. This could lead to deadlock through lock order inversion via IRQ. In addition, Linus pointed out that the temporary lock dropping and subtle three-way return value of pcpu_extend_area_map() was very ugly and suggested to split the function into two - pcpu_need_to_extend() and pcpu_extend_area_map(). This patch restructures pcpu_extend_area_map() as suggested and fixes the two bugs. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu>
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>
2009-10-29percpu: allow pcpu_alloc() to be called with IRQs offJiri Kosina
pcpu_alloc() and pcpu_extend_area_map() perform a series of spin_lock_irq()/spin_unlock_irq() calls, which make them unsafe with respect to being called from contexts which have IRQs off. This patch converts the code to perform save/restore of flags instead, making pcpu_alloc() (or __alloc_percpu() respectively) to be called from early kernel startup stage, where IRQs are off. This is needed for proper initialization of per-cpu rq_weight data from sched_init(). tj: added comment explaining why irqsave/restore is used in alloc path. Signed-off-by: Jiri Kosina <jkosina@suse.cz> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-10-12Merge branch 'for-linus' into for-nextTejun Heo
2009-10-12percpu: fix compile warningsTejun Heo
Fix the following two compile warnings which show up on i386. mm/percpu.c:1873: warning: comparison of distinct pointer types lacks a cast mm/percpu.c:1879: warning: format '%lx' expects type 'long unsigned int', but argument 2 has type 'size_t' Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
2009-10-02percpu: kill legacy percpu allocatorTejun Heo
With ia64 converted, there's no arch left which still uses legacy percpu allocator. Kill it. Signed-off-by: Tejun Heo <tj@kernel.org> Delightedly-acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@redhat.com> Cc: Christoph Lameter <cl@linux-foundation.org>
2009-09-29percpu: make allocation failures more verboseTejun Heo
Warn and dump stack when percpu allocation fails. percpu allocator is still young and unchecked NULL percpu pointer usage can result in random memory corruption when combined with the pointer shifting in access macros. Allocation failures should be rare and the warning message will be disabled after certain times. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29percpu: make pcpu_setup_first_chunk() failures more verboseTejun Heo
The parameters to pcpu_setup_first_chunk() come from different sources depending on architecture and can be quite complex. The function runs various sanity checks on the parameters and triggers BUG() if something isn't right. However, this is very early during the boot and not reporting exactly what the problem is makes debugging even harder. Add PCPU_SETUP_BUG() macro which prints out enough information about the parameters. As the macro still puts separate BUG() for each check, it won't lose any information even on the situations where only the program counter can be retrieved. While at it, also bump pcpu_dump_alloc_info() message to KERN_INFO so that it's visible on the console if boot fails to complete. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29percpu: make embedding first chunk allocator check vmalloc space sizeTejun Heo
Embedding first chunk allocator maintains the distances between units in the vmalloc area and thus needs vmalloc space to be larger than the maximum distances between units; otherwise, it wouldn't be able to create any dynamic chunks. This patch makes the embedding first chunk allocator check vmalloc space size and if the maximum distance between units is larger than 75% of it, print warning and, if page mapping allocator is available, fail initialization so that the system falls back onto it. This should work around percpu allocation failure problems on certain sparc64 configurations where distances between NUMA nodes are larger than the vmalloc area and makes percpu allocator more robust for future configurations. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29percpu: make pcpu_build_alloc_info() clear static buffersTejun Heo
pcpu_build_alloc_info() may be called multiple times when percpu is falling back to different first chunk allocator. Make it clear static buffers so that they don't contain values from previous runs. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-09-29percpu: fix unit_map[] verification in pcpu_setup_first_chunk()Tejun Heo
pcpu_setup_first_chunk() incorrectly used NR_CPUS as the impossible unit number while unit number can equal and go over NR_CPUS with sparse unit map. This triggers BUG_ON() spuriously on machines which have non-power-of-two number of cpus. Use UINT_MAX instead. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Tony Vroon <tony@linx.net>
2009-09-15Merge branch 'for-next' into for-linusTejun Heo
* pcpu_chunk_page_occupied() doesn't exist in for-next. * pcpu_chunk_addr_search() updated to use raw_smp_processor_id(). Conflicts: mm/percpu.c
2009-09-01percpu: don't assume existence of cpu0Tejun Heo
percpu incorrectly assumed that cpu0 was always there which led to the following warning and eventual oops on sparc machines w/o cpu0. WARNING: at mm/percpu.c:651 pcpu_map+0xdc/0x100() Modules linked in: Call Trace: [000000000045eb70] warn_slowpath_common+0x50/0xa0 [000000000045ebdc] warn_slowpath_null+0x1c/0x40 [00000000004d493c] pcpu_map+0xdc/0x100 [00000000004d59a4] pcpu_alloc+0x3e4/0x4e0 [00000000004d5af8] __alloc_percpu+0x18/0x40 [00000000005b112c] __percpu_counter_init+0x4c/0xc0 ... Unable to handle kernel NULL pointer dereference ... I7: <sysfs_new_dirent+0x30/0x120> Disabling lock debugging due to kernel taint Caller[000000000053c1b0]: sysfs_new_dirent+0x30/0x120 Caller[000000000053c7a4]: create_dir+0x24/0xc0 Caller[000000000053c870]: sysfs_create_dir+0x30/0x80 Caller[00000000005990e8]: kobject_add_internal+0xc8/0x200 ... Kernel panic - not syncing: Attempted to kill the idle task! This patch fixes the problem by backporting parts from devel branch to make percpu core not depend on the existence of cpu0. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Meelis Roos <mroos@linux.ee> Cc: David Miller <davem@davemloft.net>
2009-08-14percpu: kill lpage first chunk allocatorTejun Heo
With x86 converted to embedding allocator, lpage doesn't have any user left. Kill it along with cpa handling code. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Beulich <JBeulich@novell.com>
2009-08-14percpu: update embedding first chunk allocator to handle sparse unitsTejun Heo
Now that percpu core can handle very sparse units, given that vmalloc space is large enough, embedding first chunk allocator can use any memory to build the first chunk. This patch teaches pcpu_embed_first_chunk() about distances between cpus and to use alloc/free callbacks to allocate node specific areas for each group and use them for the first chunk. This brings the benefits of embedding allocator to NUMA configurations - no extra TLB pressure with the flexibility of unified dynamic allocator and no need to restructure arch code to build memory layout suitable for percpu. With units put into atom_size aligned groups according to cpu distances, using large page for dynamic chunks is also easily possible with falling back to reuglar pages if large allocation fails. Embedding allocator users are converted to specify NULL cpu_distance_fn, so this patch doesn't cause any visible behavior difference. Following patches will convert them. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: use group information to allocate vmap areas sparselyTejun Heo
ai->groups[] contains which units need to be put consecutively and at what offset from the chunk base address. Compile this information into pcpu_group_offsets[] and pcpu_group_sizes[] in pcpu_setup_first_chunk() and use them to allocate sparse vm areas using pcpu_get_vm_areas(). This will be used to allow directly using sparse NUMA memories as percpu areas. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Nick Piggin <npiggin@suse.de>
2009-08-14percpu: add chunk->base_addrTejun Heo
The only thing percpu allocator wants to know about a vmalloc area is the base address. Instead of requiring chunk->vm, add chunk->base_addr which contains the necessary value. This simplifies the code a bit and makes the dummy first_vm unnecessary. This change will ease allowing a chunk to be mapped by multiple vms. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: add pcpu_unit_offsets[]Tejun Heo
Currently units are mapped sequentially into address space. This patch adds pcpu_unit_offsets[] which allows units to be mapped to arbitrary offsets from the chunk base address. This is necessary to allow sparse embedding which might would need to allocate address ranges and memory areas which aren't aligned to unit size but allocation atom size (page or large page size). This also simplifies things a bit by removing the need to calculate offset from unit number. With this change, there's no need for the arch code to know pcpu_unit_size. Update pcpu_setup_first_chunk() and first chunk allocators to return regular 0 or -errno return code instead of unit size or -errno. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David S. Miller <davem@davemloft.net>
2009-08-14percpu: introduce pcpu_alloc_info and pcpu_group_infoTejun Heo
Till now, non-linear cpu->unit map was expressed using an integer array which maps each cpu to a unit and used only by lpage allocator. Although how many units have been placed in a single contiguos area (group) is known while building unit_map, the information is lost when the result is recorded into the unit_map array. For lpage allocator, as all allocations are done by lpages and whether two adjacent lpages are in the same group or not is irrelevant, this didn't cause any problem. Non-linear cpu->unit mapping will be used for sparse embedding and this grouping information is necessary for that. This patch introduces pcpu_alloc_info which contains all the information necessary for initializing percpu allocator. pcpu_alloc_info contains array of pcpu_group_info which describes how units are grouped and mapped to cpus. pcpu_group_info also has base_offset field to specify its offset from the chunk's base address. pcpu_build_alloc_info() initializes this field as if all groups are allocated back-to-back as is currently done but this will be used to sparsely place groups. pcpu_alloc_info is a rather complex data structure which contains a flexible array which in turn points to nested cpu_map arrays. * pcpu_alloc_alloc_info() and pcpu_free_alloc_info() are provided to help dealing with pcpu_alloc_info. * pcpu_lpage_build_unit_map() is updated to build pcpu_alloc_info, generalized and renamed to pcpu_build_alloc_info(). @cpu_distance_fn may be NULL indicating that all cpus are of LOCAL_DISTANCE. * pcpul_lpage_dump_cfg() is updated to process pcpu_alloc_info, generalized and renamed to pcpu_dump_alloc_info(). It now also prints which group each alloc unit belongs to. * pcpu_setup_first_chunk() now takes pcpu_alloc_info instead of the separate parameters. All first chunk allocators are updated to use pcpu_build_alloc_info() to build alloc_info and call pcpu_setup_first_chunk() with it. This has the side effect of packing units for sparse possible cpus. ie. if cpus 0, 2 and 4 are possible, they'll be assigned unit 0, 1 and 2 instead of 0, 2 and 4. * x86 setup_pcpu_lpage() is updated to deal with alloc_info. * sparc64 setup_per_cpu_areas() is updated to build alloc_info. Although the changes made by this patch are pretty pervasive, it doesn't cause any behavior difference other than packing of sparse cpus. It mostly changes how information is passed among initialization functions and makes room for more flexibility. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net>
2009-08-14percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upwardTejun Heo
Unit map handling will be generalized and extended and used for embedding sparse first chunk and other purposes. Relocate two unit_map related functions upward in preparation. This patch just moves the code without any actual change. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: add @align to pcpu_fc_alloc_fn_tTejun Heo
pcpu_fc_alloc_fn_t is about to see more interesting usage, add @align parameter. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()Tejun Heo
Now that all actual first chunk allocation and copying happen in the first chunk allocators and helpers, there's no reason for pcpu_setup_first_chunk() to try to determine @dyn_size automatically. The only left user is page first chunk allocator. Make it determine dyn_size like other allocators and make @dyn_size mandatory for pcpu_setup_first_chunk(). Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: drop @static_size from first chunk allocatorsTejun Heo
First chunk allocators assume percpu areas have been linked using one of PERCPU_*() macros and depend on __per_cpu_load symbol defined by those macros, so there isn't much point in passing in static area size explicitly when it can be easily calculated from __per_cpu_start and __per_cpu_end. Drop @static_size from all percpu first chunk allocators and helpers. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: generalize first chunk allocator selectionTejun Heo
Now that all first chunk allocators are in mm/percpu.c, it makes sense to make generalize percpu_alloc kernel parameter. Define PCPU_FC_* and set pcpu_chosen_fc using early_param() in mm/percpu.c. Arch code can use the set value to determine which first chunk allocator to use. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: build first chunk allocators selectivelyTejun Heo
There's no need to build unused first chunk allocators in. Define CONFIG_NEED_PER_CPU_*_FIRST_CHUNK and let archs enable them selectively. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: rename 4k first chunk allocator to pageTejun Heo
Page size isn't always 4k depending on arch and configuration. Rename 4k first chunk allocator to page. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David Howells <dhowells@redhat.com>
2009-08-14percpu: improve boot messagesTejun Heo
Improve percpu boot messages such that they're uniform and contain more information. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
2009-08-14percpu: fix pcpu_reclaim() lockingTejun Heo
pcpu_reclaim() calls pcpu_depopulate_chunk() which makes use of pages array and bitmap returned by pcpu_get_pages_and_bitmap() and thus should be called under pcpu_alloc_mutex. pcpu_reclaim() released the mutex before calling depopulate leading to double free and other strange problems caused by the unexpected concurrent usages of pages array and bitmap. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
2009-08-14Merge branch 'percpu-for-linus' into percpu-for-nextTejun Heo
Conflicts: arch/sparc/kernel/smp_64.c arch/x86/kernel/cpu/perf_counter.c arch/x86/kernel/setup_percpu.c drivers/cpufreq/cpufreq_ondemand.c mm/percpu.c Conflicts in core and arch percpu codes are mostly from commit ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many num_possible_cpus() with nr_cpu_ids. As for-next branch has moved all the first chunk allocators into mm/percpu.c, the changes are moved from arch code to mm/percpu.c. Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14percpu: use the right flag for get_vm_area()Amerigo Wang
get_vm_area() only accepts VM_* flags, not GFP_*. And according to the doc of get_vm_area(), here should be VM_ALLOC. Signed-off-by: WANG Cong <amwang@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-08-14percpu, sparc64: fix sparse possible cpu map handlingTejun Heo
percpu code has been assuming num_possible_cpus() == nr_cpu_ids which is incorrect if cpu_possible_map contains holes. This causes percpu code to access beyond allocated memories and vmalloc areas. On a sparc64 machine with cpus 0 and 2 (u60), this triggers the following warning or fails boot. WARNING: at /devel/tj/os/work/mm/vmalloc.c:106 vmap_page_range_noflush+0x1f0/0x240() Modules linked in: Call Trace: [00000000004b17d0] vmap_page_range_noflush+0x1f0/0x240 [00000000004b1840] map_vm_area+0x20/0x60 [00000000004b1950] __vmalloc_area_node+0xd0/0x160 [0000000000593434] deflate_init+0x14/0xe0 [0000000000583b94] __crypto_alloc_tfm+0xd4/0x1e0 [00000000005844f0] crypto_alloc_base+0x50/0xa0 [000000000058b898] alg_test_comp+0x18/0x80 [000000000058dad4] alg_test+0x54/0x180 [000000000058af00] cryptomgr_test+0x40/0x60 [0000000000473098] kthread+0x58/0x80 [000000000042b590] kernel_thread+0x30/0x60 [0000000000472fd0] kthreadd+0xf0/0x160 ---[ end trace 429b268a213317ba ]--- This patch fixes generic percpu functions and sparc64 setup_per_cpu_areas() so that they handle sparse cpu_possible_map properly. Please note that on x86, cpu_possible_map() doesn't contain holes and thus num_possible_cpus() == nr_cpu_ids and this patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu>
2009-07-04percpu: teach large page allocator about NUMATejun Heo
Large page first chunk allocator is primarily used for NUMA machines; however, its NUMA handling is extremely simplistic. Regardless of their proximity, each cpu is put into separate large page just to return most of the allocated space back wasting large amount of vmalloc space and increasing cache footprint. This patch teachs NUMA details to large page allocator. Given processor proximity information, pcpu_lpage_build_unit_map() will find fitting cpu -> unit mapping in which cpus in LOCAL_DISTANCE share the same large page and not too much virtual address space is wasted. This greatly reduces the unit and thus chunk size and wastes much less address space for the first chunk. For example, on 4/4 NUMA machine, the original code occupied 16MB of virtual space for the first chunk while the new code only uses 4MB - one 2MB page for each node. [ Impact: much better space efficiency on NUMA machines ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jan Beulich <JBeulich@novell.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: David Miller <davem@davemloft.net>
2009-07-04percpu: allow non-linear / sparse cpu -> unit mappingTejun Heo
Currently cpu and unit are always identity mapped. To allow more efficient large page support on NUMA and lazy allocation for possible but offline cpus, cpu -> unit mapping needs to be non-linear and/or sparse. This can be easily implemented by adding a cpu -> unit mapping array and using it whenever looking up the matching unit for a cpu. The only unusal conversion is in pcpu_chunk_addr_search(). The passed in address is unit0 based and unit0 might not be in use so it needs to be converted to address of an in-use unit. This is easily done by adding the unit offset for the current processor. [ Impact: allows non-linear/sparse cpu -> unit mapping, no visible change yet ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net>
2009-07-04percpu: drop pcpu_chunk->page[]Tejun Heo
percpu core doesn't need to tack all the allocated pages. It needs to know whether certain pages are populated and a way to reverse map address to page when freeing. This patch drops pcpu_chunk->page[] and use populated bitmap and vmalloc_to_page() lookup instead. Using vmalloc_to_page() exclusively is also possible but complicates first chunk handling, inflates cache footprint and prevents non-standard memory allocation for percpu memory. pcpu_chunk->page[] was used to track each page's allocation and allowed asymmetric population which happens during failure path; however, with single bitmap for all units, this is no longer possible. Bite the bullet and rewrite (de)populate functions so that things are done in clearly separated steps such that asymmetric population doesn't happen. This makes the (de)population process much more modular and will also ease implementing non-standard memory usage in the future (e.g. large pages). This makes @get_page_fn parameter to pcpu_setup_first_chunk() unnecessary. The parameter is dropped and all first chunk helpers are updated accordingly. Please note that despite the volume most changes to first chunk helpers are symbol renames for variables which don't need to be referenced outside of the helper anymore. This change reduces memory usage and cache footprint of pcpu_chunk. Now only #unit_pages bits are necessary per chunk. [ Impact: reduced memory usage and cache footprint for bookkeeping ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net>
2009-07-04percpu: reorder a few functions in mm/percpu.cTejun Heo
(de)populate functions are about to be reimplemented to drop pcpu_chunk->page array. Move a few functions so that the rewrite patch doesn't have code movement making it more difficult to read. [ Impact: code movement ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-07-04percpu: simplify pcpu_setup_first_chunk()Tejun Heo
Now that all first chunk allocator helpers allocate and map the first chunk themselves, there's no need to have optional default alloc/map in pcpu_setup_first_chunk(). Drop @populate_pte_fn and only leave @dyn_size optional and make all other params mandatory. This makes it much easier to follow what pcpu_setup_first_chunk() is doing and what actual differences tweaking each parameter results in. [ Impact: drop unused code path ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>
2009-07-04x86,percpu: generalize lpage first chunk allocatorTejun Heo
Generalize and move x86 setup_pcpu_lpage() into pcpu_lpage_first_chunk(). setup_pcpu_lpage() now is a simple wrapper around the generalized version. Other than taking size parameters and using arch supplied callbacks to allocate/free/map memory, pcpu_lpage_first_chunk() is identical to the original implementation. This simplifies arch code and will help converting more archs to dynamic percpu allocator. While at it, factor out pcpu_calc_fc_sizes() which is common to pcpu_embed_first_chunk() and pcpu_lpage_first_chunk(). [ Impact: code reorganization and generalization ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@elte.hu>