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 --- lib/prio_heap.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 lib/prio_heap.c (limited to 'lib/prio_heap.c') diff --git a/lib/prio_heap.c b/lib/prio_heap.c new file mode 100644 index 000000000000..471944a54e23 --- /dev/null +++ b/lib/prio_heap.c @@ -0,0 +1,70 @@ +/* + * Simple insertion-only static-sized priority heap containing + * pointers, based on CLR, chapter 7 + */ + +#include +#include + +int heap_init(struct ptr_heap *heap, size_t size, gfp_t gfp_mask, + int (*gt)(void *, void *)) +{ + heap->ptrs = kmalloc(size, gfp_mask); + if (!heap->ptrs) + return -ENOMEM; + heap->size = 0; + heap->max = size / sizeof(void *); + heap->gt = gt; + return 0; +} + +void heap_free(struct ptr_heap *heap) +{ + kfree(heap->ptrs); +} + +void *heap_insert(struct ptr_heap *heap, void *p) +{ + void *res; + void **ptrs = heap->ptrs; + int pos; + + if (heap->size < heap->max) { + /* Heap insertion */ + int pos = heap->size++; + while (pos > 0 && heap->gt(p, ptrs[(pos-1)/2])) { + ptrs[pos] = ptrs[(pos-1)/2]; + pos = (pos-1)/2; + } + ptrs[pos] = p; + return NULL; + } + + /* The heap is full, so something will have to be dropped */ + + /* If the new pointer is greater than the current max, drop it */ + if (heap->gt(p, ptrs[0])) + return p; + + /* Replace the current max and heapify */ + res = ptrs[0]; + ptrs[0] = p; + pos = 0; + + while (1) { + int left = 2 * pos + 1; + int right = 2 * pos + 2; + int largest = pos; + if (left < heap->size && heap->gt(ptrs[left], p)) + largest = left; + if (right < heap->size && heap->gt(ptrs[right], ptrs[largest])) + largest = right; + if (largest == pos) + break; + /* Push p down the heap one level and bump one up */ + ptrs[pos] = ptrs[largest]; + ptrs[largest] = p; + pos = largest; + } + return res; +} -- cgit v1.2.3