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authorMel Gorman <mel@csn.ul.ie>2007-10-16 12:25:59 +0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-16 20:43:00 +0400
commit64c5e135bf5a2a7f0ededb3435a31adbe0202f0c (patch)
treecb4ff93cbcc3c27176723419a313d7c53545d36b /include/linux/pageblock-flags.h
parentac0e5b7a6b93fb291b01fe1e951e3c16bcdd3503 (diff)
downloadlinux-64c5e135bf5a2a7f0ededb3435a31adbe0202f0c.tar.xz
don't group high order atomic allocations
Grouping high-order atomic allocations together was intended to allow bursty users of atomic allocations to work such as e1000 in situations where their preallocated buffers were depleted. This did not work in at least one case with a wireless network adapter needing order-1 allocations frequently. To resolve that, the free pages used for min_free_kbytes were moved to separate contiguous blocks with the patch bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks. It is felt that keeping the free pages in the same contiguous blocks should be sufficient for bursty short-lived high-order atomic allocations to succeed, maybe even with the e1000. Even if there is a failure, increasing the value of min_free_kbytes will free pages as contiguous bloks in contrast to the standard buddy allocator which makes no attempt to keep the minimum number of free pages contiguous. This patch backs out grouping high order atomic allocations together to determine if it is really needed or not. If a new report comes in about high-order atomic allocations failing, the feature can be reintroduced to determine if it fixes the problem or not. As a side-effect, this patch reduces by 1 the number of bits required to track the mobility type of pages within a MAX_ORDER_NR_PAGES block. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pageblock-flags.h')
-rw-r--r--include/linux/pageblock-flags.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index fa3b1001894b..5456da6b4ade 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -31,7 +31,7 @@
/* Bit indices that affect a whole block of pages */
enum pageblock_bits {
- PB_range(PB_migrate, 3), /* 3 bits required for migrate types */
+ PB_range(PB_migrate, 2), /* 2 bits required for migrate types */
NR_PAGEBLOCK_BITS
};