Messages in this thread |  | | Subject | Re: [PATCH] mm/page_alloc: Do not isolate redundant pageblock | From | Vlastimil Babka <> | Date | Fri, 27 Nov 2020 16:17:36 +0100 |
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On 11/27/20 3:19 PM, Muchun Song wrote: > Current pageblock isolation logic could isolate each pageblock individually > since commit d9dddbf55667 ("mm/page_alloc: prevent merging between isolated > and other pageblocks"). So we not need to concern about page allocator > merges buddies from different pageblocks and changes MIGRATE_ISOLATE to > some other migration type.
Yeah, that should be the case now.
> Signed-off-by: Muchun Song <songmuchun@bytedance.com> > --- > mm/page_alloc.c | 26 ++++++++------------------ > 1 file changed, 8 insertions(+), 18 deletions(-) > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index cefbef32bf4a..608a2c2b8ab7 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -8313,16 +8313,14 @@ struct page *has_unmovable_pages(struct zone *zone, struct page *page, > } > > #ifdef CONFIG_CONTIG_ALLOC > -static unsigned long pfn_max_align_down(unsigned long pfn) > +static unsigned long pfn_align_down(unsigned long pfn) > { > - return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES, > - pageblock_nr_pages) - 1); > + return pfn & ~(pageblock_nr_pages - 1); > } > > -static unsigned long pfn_max_align_up(unsigned long pfn) > +static unsigned long pfn_align_up(unsigned long pfn) > { > - return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES, > - pageblock_nr_pages)); > + return ALIGN(pfn, pageblock_nr_pages); > }
How bout just removing these wrappers completely and using ALIGN and ALIGN_DOWN directly, as there are just two uses for each?
> /* [start, end) must belong to a single zone. */ > @@ -8415,14 +8413,6 @@ int alloc_contig_range(unsigned long start, unsigned long end, > INIT_LIST_HEAD(&cc.migratepages); > > /* > - * What we do here is we mark all pageblocks in range as > - * MIGRATE_ISOLATE. Because pageblock and max order pages may > - * have different sizes, and due to the way page allocator > - * work, we align the range to biggest of the two pages so > - * that page allocator won't try to merge buddies from > - * different pageblocks and change MIGRATE_ISOLATE to some > - * other migration type. > - * > * Once the pageblocks are marked as MIGRATE_ISOLATE, we > * migrate the pages from an unaligned range (ie. pages that > * we are interested in). This will put all the pages in > @@ -8438,8 +8428,8 @@ int alloc_contig_range(unsigned long start, unsigned long end, > * put back to page allocator so that buddy can use them. > */ > > - ret = start_isolate_page_range(pfn_max_align_down(start), > - pfn_max_align_up(end), migratetype, 0); > + ret = start_isolate_page_range(pfn_align_down(start), pfn_align_up(end), > + migratetype, 0); > if (ret) > return ret; > > @@ -8522,8 +8512,8 @@ int alloc_contig_range(unsigned long start, unsigned long end, > free_contig_range(end, outer_end - end); > > done: > - undo_isolate_page_range(pfn_max_align_down(start), > - pfn_max_align_up(end), migratetype); > + undo_isolate_page_range(pfn_align_down(start), pfn_align_up(end), > + migratetype); > return ret; > } > EXPORT_SYMBOL(alloc_contig_range); >
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