From 8707d8b8c0cbdf4441507f8dded194167da896c7 Mon Sep 17 00:00:00 2001 From: Paul Menage Date: Thu, 18 Oct 2007 23:40:22 -0700 Subject: Fix cpusets update_cpumask Cause writes to cpuset "cpus" file to update cpus_allowed for member tasks: - collect batches of tasks under tasklist_lock and then call set_cpus_allowed() on them outside the lock (since this can sleep). - add a simple generic priority heap type to allow efficient collection of batches of tasks to be processed without duplicating or missing any tasks in subsequent batches. - make "cpus" file update a no-op if the mask hasn't changed - fix race between update_cpumask() and sched_setaffinity() by making sched_setaffinity() post-check that it's not running on any cpus outside cpuset_cpus_allowed(). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Paul Menage Cc: Paul Jackson Cc: David Rientjes Cc: Nick Piggin Cc: Peter Zijlstra Cc: Balbir Singh Cc: Cedric Le Goater Cc: "Eric W. Biederman" Cc: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/prio_heap.h | 58 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) create mode 100644 include/linux/prio_heap.h (limited to 'include') diff --git a/include/linux/prio_heap.h b/include/linux/prio_heap.h new file mode 100644 index 00000000000..08094350f26 --- /dev/null +++ b/include/linux/prio_heap.h @@ -0,0 +1,58 @@ +#ifndef _LINUX_PRIO_HEAP_H +#define _LINUX_PRIO_HEAP_H + +/* + * Simple insertion-only static-sized priority heap containing + * pointers, based on CLR, chapter 7 + */ + +#include + +/** + * struct ptr_heap - simple static-sized priority heap + * @ptrs - pointer to data area + * @max - max number of elements that can be stored in @ptrs + * @size - current number of valid elements in @ptrs (in the range 0..@size-1 + * @gt: comparison operator, which should implement "greater than" + */ +struct ptr_heap { + void **ptrs; + int max; + int size; + int (*gt)(void *, void *); +}; + +/** + * heap_init - initialize an empty heap with a given memory size + * @heap: the heap structure to be initialized + * @size: amount of memory to use in bytes + * @gfp_mask: mask to pass to kmalloc() + * @gt: comparison operator, which should implement "greater than" + */ +extern int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask, + int (*gt)(void *, void *)); + +/** + * heap_free - release a heap's storage + * @heap: the heap structure whose data should be released + */ +void heap_free(struct ptr_heap *heap); + +/** + * heap_insert - insert a value into the heap and return any overflowed value + * @heap: the heap to be operated on + * @p: the pointer to be inserted + * + * Attempts to insert the given value into the priority heap. If the + * heap is full prior to the insertion, then the resulting heap will + * consist of the smallest @max elements of the original heap and the + * new element; the greatest element will be removed from the heap and + * returned. Note that the returned element will be the new element + * (i.e. no change to the heap) if the new element is greater than all + * elements currently in the heap. + */ +extern void *heap_insert(struct ptr_heap *heap, void *p); + + + +#endif /* _LINUX_PRIO_HEAP_H */ -- cgit v1.2.3