Messages in this thread | | | Date | Tue, 16 Jul 2013 21:02:53 +0800 | From | Sam Ben <> | Subject | Re: [RFC 2/4] Have __free_pages_memory() free in larger chunks. |
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Hi Robin, On 07/12/2013 10:03 AM, Robin Holt wrote: > 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. In order to be able to
I fail to understand this. Why the original page number is BITS_PER_LONG?
> free only the first page of a 2MiB chunk, we need that to be increased > to PTRS_PER_PMD. > > Signed-off-by: Robin Holt <holt@sgi.com> > Signed-off-by: Nate Zimmer <nzimmer@sgi.com> > To: "H. Peter Anvin" <hpa@zytor.com> > To: Ingo Molnar <mingo@kernel.org> > Cc: Linux Kernel <linux-kernel@vger.kernel.org> > Cc: Linux MM <linux-mm@kvack.org> > Cc: Rob Landley <rob@landley.net> > Cc: Mike Travis <travis@sgi.com> > Cc: Daniel J Blueman <daniel@numascale-asia.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Greg KH <gregkh@linuxfoundation.org> > Cc: Yinghai Lu <yinghai@kernel.org> > Cc: Mel Gorman <mgorman@suse.de> > --- > mm/nobootmem.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/mm/nobootmem.c b/mm/nobootmem.c > index bdd3fa2..3b512ca 100644 > --- a/mm/nobootmem.c > +++ b/mm/nobootmem.c > @@ -83,10 +83,10 @@ void __init free_bootmem_late(unsigned long addr, unsigned long size) > 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 = ilog2(max(BITS_PER_LONG, PTRS_PER_PMD)); > > - start_aligned = (start + (BITS_PER_LONG - 1)) & ~(BITS_PER_LONG - 1); > - end_aligned = end & ~(BITS_PER_LONG - 1); > + start_aligned = (start + ((1UL << order) - 1)) & ~((1UL << order) - 1); > + end_aligned = end & ~((1UL << order) - 1); > > if (end_aligned <= start_aligned) { > for (i = start; i < end; i++) > @@ -98,7 +98,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end) > for (i = start; i < start_aligned; i++) > __free_pages_bootmem(pfn_to_page(i), 0); > > - for (i = start_aligned; i < end_aligned; i += BITS_PER_LONG) > + for (i = start_aligned; i < end_aligned; i += 1 << order) > __free_pages_bootmem(pfn_to_page(i), order); > > for (i = end_aligned; i < end; i++)
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