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-rw-r--r--mm/slab.c89
1 files changed, 49 insertions, 40 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 3d3b5a46854f..2551b1eeadb3 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1474,6 +1474,53 @@ static inline void set_up_list3s(kmem_cache_t *cachep, int index)
1474} 1474}
1475 1475
1476/** 1476/**
1477 * calculate_slab_order - calculate size (page order) of slabs and the number
1478 * of objects per slab.
1479 *
1480 * This could be made much more intelligent. For now, try to avoid using
1481 * high order pages for slabs. When the gfp() functions are more friendly
1482 * towards high-order requests, this should be changed.
1483 */
1484static inline size_t calculate_slab_order(kmem_cache_t *cachep, size_t size,
1485 size_t align, gfp_t flags)
1486{
1487 size_t left_over = 0;
1488
1489 for ( ; ; cachep->gfporder++) {
1490 unsigned int num;
1491 size_t remainder;
1492
1493 if (cachep->gfporder > MAX_GFP_ORDER) {
1494 cachep->num = 0;
1495 break;
1496 }
1497
1498 cache_estimate(cachep->gfporder, size, align, flags,
1499 &remainder, &num);
1500 if (!num)
1501 continue;
1502 /* More than offslab_limit objects will cause problems */
1503 if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit)
1504 break;
1505
1506 cachep->num = num;
1507 left_over = remainder;
1508
1509 /*
1510 * Large number of objects is good, but very large slabs are
1511 * currently bad for the gfp()s.
1512 */
1513 if (cachep->gfporder >= slab_break_gfp_order)
1514 break;
1515
1516 if ((left_over * 8) <= (PAGE_SIZE << cachep->gfporder))
1517 /* Acceptable internal fragmentation */
1518 break;
1519 }
1520 return left_over;
1521}
1522
1523/**
1477 * kmem_cache_create - Create a cache. 1524 * kmem_cache_create - Create a cache.
1478 * @name: A string which is used in /proc/slabinfo to identify this cache. 1525 * @name: A string which is used in /proc/slabinfo to identify this cache.
1479 * @size: The size of objects to be created in this cache. 1526 * @size: The size of objects to be created in this cache.
@@ -1682,46 +1729,8 @@ kmem_cache_create (const char *name, size_t size, size_t align,
1682 cachep->gfporder = 0; 1729 cachep->gfporder = 0;
1683 cache_estimate(cachep->gfporder, size, align, flags, 1730 cache_estimate(cachep->gfporder, size, align, flags,
1684 &left_over, &cachep->num); 1731 &left_over, &cachep->num);
1685 } else { 1732 } else
1686 /* 1733 left_over = calculate_slab_order(cachep, size, align, flags);
1687 * Calculate size (in pages) of slabs, and the num of objs per
1688 * slab. This could be made much more intelligent. For now,
1689 * try to avoid using high page-orders for slabs. When the
1690 * gfp() funcs are more friendly towards high-order requests,
1691 * this should be changed.
1692 */
1693 do {
1694 unsigned int break_flag = 0;
1695cal_wastage:
1696 cache_estimate(cachep->gfporder, size, align, flags,
1697 &left_over, &cachep->num);
1698 if (break_flag)
1699 break;
1700 if (cachep->gfporder >= MAX_GFP_ORDER)
1701 break;
1702 if (!cachep->num)
1703 goto next;
1704 if (flags & CFLGS_OFF_SLAB &&
1705 cachep->num > offslab_limit) {
1706 /* This num of objs will cause problems. */
1707 cachep->gfporder--;
1708 break_flag++;
1709 goto cal_wastage;
1710 }
1711
1712 /*
1713 * Large num of objs is good, but v. large slabs are
1714 * currently bad for the gfp()s.
1715 */
1716 if (cachep->gfporder >= slab_break_gfp_order)
1717 break;
1718
1719 if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder))
1720 break; /* Acceptable internal fragmentation. */
1721next:
1722 cachep->gfporder++;
1723 } while (1);
1724 }
1725 1734
1726 if (!cachep->num) { 1735 if (!cachep->num) {
1727 printk("kmem_cache_create: couldn't create cache %s.\n", name); 1736 printk("kmem_cache_create: couldn't create cache %s.\n", name);