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Fix cpusets update_cpumask

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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 <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Paul Menage 2007-10-18 23:40:22 -07:00 • committed by Linus Torvalds
parent 020958b627
commit 8707d8b8c0
5 changed files with 243 additions and 5 deletions
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58
include/linux/prio_heap.h Normal file
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#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 <linux/gfp.h>
/**
* 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 */