| Message ID | 20230826154745.4019371-3-shikemeng@huaweicloud.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Fixes and cleanups to break_down_buddy_pages | expand |
On Sat, Aug 26, 2023 at 11:47:44PM +0800, Kemeng Shi wrote: > 1. We always have target in range started with next_page and full free > range started with current_buddy. > 2. The last splited range size is 1 << low and low should be >= 0, then s/splited/split/ > size >= 1, then page + size and page will not interleave. I'm not sure the meaning of "interleave" here, maybe simply meaning "page + size != page is always true (because size > 0)". > As summary, current_page will not equal to target page. > > Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> But I agree with the summary. So with updating description... Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> > --- > mm/page_alloc.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 88c5f5aea9b0..bb74b40dc195 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -6510,10 +6510,8 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, > if (set_page_guard(zone, current_buddy, high, migratetype)) > continue; > > - if (current_buddy != target) { > - add_to_free_list(current_buddy, zone, high, migratetype); > - set_buddy_order(current_buddy, high); > - } > + add_to_free_list(current_buddy, zone, high, migratetype); > + set_buddy_order(current_buddy, high); > } > } > > -- > 2.30.0 > > >
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 88c5f5aea9b0..bb74b40dc195 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6510,10 +6510,8 @@ static void break_down_buddy_pages(struct zone *zone, struct page *page, if (set_page_guard(zone, current_buddy, high, migratetype)) continue; - if (current_buddy != target) { - add_to_free_list(current_buddy, zone, high, migratetype); - set_buddy_order(current_buddy, high); - } + add_to_free_list(current_buddy, zone, high, migratetype); + set_buddy_order(current_buddy, high); } }
1. We always have target in range started with next_page and full free range started with current_buddy. 2. The last splited range size is 1 << low and low should be >= 0, then size >= 1, then page + size and page will not interleave. As summary, current_page will not equal to target page. Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com> --- mm/page_alloc.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)