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 <[email protected]>
Signed-off-by: Nathan Zimmer <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Mike Travis <[email protected]>
Cc: Yinghai Lu <[email protected]>
Cc: Mel Gorman <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Reviewed-by: Wanpeng Li <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions