kernel/git/stable/linux.git/mm/percpu.c, branch linux-2.6.33.y

percpu: fix pcpu_last_unit_cpu

2011-03-21T19:45:44+00:00

commit 46b30ea9bc3698bc1d1e6fd726c9601d46fa0a91 upstream. pcpu_first/last_unit_cpu are used to track which cpu has the first and last units assigned. This in turn is used to determine the span of a chunk for man/unmap cache flushes and whether an address belongs to the first chunk or not in per_cpu_ptr_to_phys(). When the number of possible CPUs isn't power of two, a chunk may contain unassigned units towards the end of a chunk. The logic to determine pcpu_last_unit_cpu was incorrect when there was an unused unit at the end of a chunk. It failed to ignore the unused unit and assigned the unused marker NR_CPUS to pcpu_last_unit_cpu. This was discovered through kdump failure which was caused by malfunctioning per_cpu_ptr_to_phys() on a kvm setup with 50 possible CPUs by CAI Qian. Signed-off-by: Tejun Heo Reported-by: CAI Qian Signed-off-by: Greg Kroah-Hartman

percpu: avoid calling __pcpu_ptr_to_addr(NULL)

2010-01-11T17:34:04+00:00

__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 Cc: Kamalesh Babulal Acked-by: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' into for-next

2009-12-08T01:02:12+00:00

Conflicts: mm/percpu.c

percpu: Fix kdump failure if booted with percpu_alloc=page

2009-11-25T12:49:22+00:00

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 Signed-off-by: Tejun Heo Cc: Stephen Rothwell

percpu: restructure pcpu_extend_area_map() to fix bugs and improve readability

2009-11-12T15:55:35+00:00

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 Acked-by: Linus Torvalds Cc: Ingo Molnar

percpu: remove some sparse warnings

2009-10-29T13:34:12+00:00

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 Reviewed-by: Christoph Lameter Cc: Rusty Russell

percpu: allow pcpu_alloc() to be called with IRQs off

2009-10-28T15:25:59+00:00

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 Acked-by: Ingo Molnar Signed-off-by: Tejun Heo

Merge branch 'for-linus' into for-next

2009-10-12T08:14:18+00:00

percpu: fix compile warnings

2009-10-12T08:04:42+00:00

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 Reported-by: Randy Dunlap

percpu: kill legacy percpu allocator

2009-10-02T04:29:29+00:00

With ia64 converted, there's no arch left which still uses legacy percpu allocator. Kill it. Signed-off-by: Tejun Heo Delightedly-acked-by: Rusty Russell Cc: Ingo Molnar Cc: Christoph Lameter