On Tue, 27 Mar 2018, Wei Yang wrote:
> >> In 'commit c4e1be9ec113 ("mm, sparsemem: break out of loops early")',
> >> __highest_present_section_nr is introduced to reduce the loop counts for
> >> present section. This is also helpful for usemap and memmap allocation.
> >>
> >> This patch uses __highest_present_section_nr + 1 to optimize the loop.
> >>
> >> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> >> ---
> >> mm/sparse.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/mm/sparse.c b/mm/sparse.c
> >> index 7af5e7a92528..505050346249 100644
> >> --- a/mm/sparse.c
> >> +++ b/mm/sparse.c
> >> @@ -561,7 +561,7 @@ static void __init alloc_usemap_and_memmap(void (*alloc_func)
> >> map_count = 1;
> >> }
> >> /* ok, last chunk */
> >> - alloc_func(data, pnum_begin, NR_MEM_SECTIONS,
> >> + alloc_func(data, pnum_begin, __highest_present_section_nr+1,
> >> map_count, nodeid_begin);
> >> }
> >>
> >
> >What happens if s/NR_MEM_SECTIONS/pnum/?
>
> I have tried this :-)
>
> The last pnum is -1 from next_present_section_nr().
>
Lol. I think it would make more sense for the second patch to come before
the first, but feel free to add
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
