Subject: + mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch added to -mm tree
To: robin.m.holt@xxxxxxxxx,hannes@xxxxxxxxxxx,hpa@xxxxxxxxx,mgorman@xxxxxxx,mingo@xxxxxxxxxx,nzimmer@xxxxxxx,robinmholt@xxxxxxxxx,travis@xxxxxxx,yinghai@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 19 Sep 2013 16:39:42 -0700
The patch titled
Subject: mm/nobootmem.c: have __free_pages_memory() free in larger chunks.
has been added to the -mm tree. Its filename is
mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch
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From: Robin Holt <robin.m.holt@xxxxxxxxx>
Subject: mm/nobootmem.c: have __free_pages_memory() free in larger chunks.
On large memory machines it can take a few minutes to get through
free_all_bootmem().
Currently, when free_all_bootmem() calls __free_pages_memory(), the number
of contiguous pages that __free_pages_memory() passes to the buddy
allocator is limited to BITS_PER_LONG. BITS_PER_LONG was originally
chosen to keep things similar to mm/nobootmem.c. But it is more efficient
to limit it to MAX_ORDER.
base new change
8TB 202s 172s 30s
16TB 401s 351s 50s
That is around 1%-3% improvement on total boot time.
This patch was spun off from the boot time rfc Robin and I had been
working on.
Signed-off-by: Robin Holt <robin.m.holt@xxxxxxxxx>
Signed-off-by: Nathan Zimmer <nzimmer@xxxxxxx>
Cc: Robin Holt <robinmholt@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/nobootmem.c | 25 ++++++++-----------------
1 file changed, 8 insertions(+), 17 deletions(-)
diff -puN mm/nobootmem.c~mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks mm/nobootmem.c
--- a/mm/nobootmem.c~mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks
+++ a/mm/nobootmem.c
@@ -82,27 +82,18 @@ void __init free_bootmem_late(unsigned l
static void __init __free_pages_memory(unsigned long start, unsigned long end)
{
- unsigned long i, start_aligned, end_aligned;
- int order = ilog2(BITS_PER_LONG);
+ int order;
- start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1);
- end_aligned = end & ~(BITS_PER_LONG - 1);
+ while (start < end) {
+ order = min(MAX_ORDER - 1UL, __ffs(start));
- if (end_aligned <= start_aligned) {
- for (i = start; i < end; i++)
- __free_pages_bootmem(pfn_to_page(i), 0);
+ while (start + (1UL << order) > end)
+ order--;
- return;
- }
-
- for (i = start; i < start_aligned; i++)
- __free_pages_bootmem(pfn_to_page(i), 0);
+ __free_pages_bootmem(pfn_to_page(start), order);
- for (i = start_aligned; i < end_aligned; i += BITS_PER_LONG)
- __free_pages_bootmem(pfn_to_page(i), order);
-
- for (i = end_aligned; i < end; i++)
- __free_pages_bootmem(pfn_to_page(i), 0);
+ start += (1UL << order);
+ }
}
static unsigned long __init __free_memory_core(phys_addr_t start,
_
Patches currently in -mm which might be from robin.m.holt@xxxxxxxxx are
mm-nobootmemc-have-__free_pages_memory-free-in-larger-chunks.patch
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