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Revision 3f380998aeb51b99d5d22cadb41162e1e9db70d2 authored by Kautuk Consul on 01 November 2011, 00:09:11 UTC, committed by Linus Torvalds on 01 November 2011, 00:30:49 UTC 
vmscan.c: fix invalid strict_strtoul() check in write_scan_unevictable_node()
 
write_scan_unevictable_node() checks the value req returned by
strict_strtoul() and returns 1 if req is 0.

However, when strict_strtoul() returns 0, it means successful conversion
of buf to unsigned long.

Due to this, the function was not proceeding to scan the zones for
unevictable pages even though we write a valid value to the
scan_unevictable_pages sys file.

Change this check slightly to check for invalid value in buf as well as 0
value stored in res after successful conversion via strict_strtoul.  In
both cases, we do not perform the scanning of this node's zones.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 4e9dc5d
Raw File
prio_heap.c 
/*
 * Simple insertion-only static-sized priority heap containing
 * pointers, based on CLR, chapter 7
 */

#include <linux/slab.h>
#include <linux/prio_heap.h>

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 */
		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;
}
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