| Message ID | 20220119190623.1029355-2-zi.yan@sent.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | Use pageblock_order for cma and alloc_contig_range alignment. | expand |
On Wed, Jan 19, 2022 at 02:06:17PM -0500, Zi Yan wrote: > From: Zi Yan <ziy@nvidia.com> > > This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance. > It prepares for the upcoming removal of the MAX_ORDER-1 alignment > requirement for CMA and alloc_contig_range(). > > MIGRARTE_HIGHATOMIC should not merge with other migratetypes like > MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too. > Also add MIGRARTE_HIGHATOMIC to fallbacks array for completeness. > > [1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/ > > Signed-off-by: Zi Yan <ziy@nvidia.com> > > <SNIP> > > @@ -2484,6 +2483,7 @@ static int fallbacks[MIGRATE_TYPES][3] = { > [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, > [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > + [MIGRATE_HIGHATOMIC] = { MIGRATE_TYPES }, /* Never used */ > #ifdef CONFIG_CMA > [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ > #endif If it's never used, why is it added? Otherwise looks fine so Acked-by: Mel Gorman <mgorman@techsingularity.net>
On 24 Jan 2022, at 9:02, Mel Gorman wrote: > On Wed, Jan 19, 2022 at 02:06:17PM -0500, Zi Yan wrote: >> From: Zi Yan <ziy@nvidia.com> >> >> This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance. >> It prepares for the upcoming removal of the MAX_ORDER-1 alignment >> requirement for CMA and alloc_contig_range(). >> >> MIGRARTE_HIGHATOMIC should not merge with other migratetypes like >> MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too. >> Also add MIGRARTE_HIGHATOMIC to fallbacks array for completeness. >> >> [1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/ >> >> Signed-off-by: Zi Yan <ziy@nvidia.com> >> >> <SNIP> >> >> @@ -2484,6 +2483,7 @@ static int fallbacks[MIGRATE_TYPES][3] = { >> [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, >> [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, >> [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, >> + [MIGRATE_HIGHATOMIC] = { MIGRATE_TYPES }, /* Never used */ >> #ifdef CONFIG_CMA >> [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ >> #endif > > If it's never used, why is it added? Just to make the fallbacks list complete, since MIGRATE_CMA and MIGRATE_ISOLATE are in the list. Instead, I can remove MIGRATE_CMA and MIGRATE_ISOLATE. WDYT? > > Otherwise looks fine so > > Acked-by: Mel Gorman <mgorman@techsingularity.net> Thanks. -- Best Regards, Yan, Zi
On Mon, Jan 24, 2022 at 11:12:07AM -0500, Zi Yan wrote: > On 24 Jan 2022, at 9:02, Mel Gorman wrote: > > > On Wed, Jan 19, 2022 at 02:06:17PM -0500, Zi Yan wrote: > >> From: Zi Yan <ziy@nvidia.com> > >> > >> This is done in addition to MIGRATE_ISOLATE pageblock merge avoidance. > >> It prepares for the upcoming removal of the MAX_ORDER-1 alignment > >> requirement for CMA and alloc_contig_range(). > >> > >> MIGRARTE_HIGHATOMIC should not merge with other migratetypes like > >> MIGRATE_ISOLATE and MIGRARTE_CMA[1], so this commit prevents that too. > >> Also add MIGRARTE_HIGHATOMIC to fallbacks array for completeness. > >> > >> [1] https://lore.kernel.org/linux-mm/20211130100853.GP3366@techsingularity.net/ > >> > >> Signed-off-by: Zi Yan <ziy@nvidia.com> > >> > >> <SNIP> > >> > >> @@ -2484,6 +2483,7 @@ static int fallbacks[MIGRATE_TYPES][3] = { > >> [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > >> [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, > >> [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, > >> + [MIGRATE_HIGHATOMIC] = { MIGRATE_TYPES }, /* Never used */ > >> #ifdef CONFIG_CMA > >> [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ > >> #endif > > > > If it's never used, why is it added? > > Just to make the fallbacks list complete, since MIGRATE_CMA and > MIGRATE_ISOLATE are in the list. Instead, I can remove MIGRATE_CMA and > MIGRATE_ISOLATE. WDYT? > It probably makes more sense to remove them or replace them with a comment stating what migratetypes do not have a fallback list. Do it as a separate patch that stands alone. It does not need to be part of this series.
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index aed44e9b5d89..71b77aab748d 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -83,6 +83,17 @@ static inline bool is_migrate_movable(int mt) return is_migrate_cma(mt) || mt == MIGRATE_MOVABLE; } +/* + * Check whether a migratetype can be merged with another migratetype. + * + * It is only mergeable when it can fall back to other migratetypes for + * allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c. + */ +static inline bool migratetype_is_mergeable(int mt) +{ + return mt < MIGRATE_PCPTYPES; +} + #define for_each_migratetype_order(order, type) \ for (order = 0; order < MAX_ORDER; order++) \ for (type = 0; type < MIGRATE_TYPES; type++) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 8dd6399bafb5..15de65215c02 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1117,25 +1117,24 @@ static inline void __free_one_page(struct page *page, } if (order < MAX_ORDER - 1) { /* If we are here, it means order is >= pageblock_order. - * We want to prevent merge between freepages on isolate - * pageblock and normal pageblock. Without this, pageblock - * isolation could cause incorrect freepage or CMA accounting. + * We want to prevent merge between freepages on pageblock + * without fallbacks and normal pageblock. Without this, + * pageblock isolation could cause incorrect freepage or CMA + * accounting or HIGHATOMIC accounting. * * We don't want to hit this code for the more frequent * low-order merging. */ - if (unlikely(has_isolate_pageblock(zone))) { - int buddy_mt; + int buddy_mt; - buddy_pfn = __find_buddy_pfn(pfn, order); - buddy = page + (buddy_pfn - pfn); - buddy_mt = get_pageblock_migratetype(buddy); + buddy_pfn = __find_buddy_pfn(pfn, order); + buddy = page + (buddy_pfn - pfn); + buddy_mt = get_pageblock_migratetype(buddy); - if (migratetype != buddy_mt - && (is_migrate_isolate(migratetype) || - is_migrate_isolate(buddy_mt))) - goto done_merging; - } + if (migratetype != buddy_mt + && (!migratetype_is_mergeable(migratetype) || + !migratetype_is_mergeable(buddy_mt))) + goto done_merging; max_order = order + 1; goto continue_merging; } @@ -2484,6 +2483,7 @@ static int fallbacks[MIGRATE_TYPES][3] = { [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES }, [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES }, + [MIGRATE_HIGHATOMIC] = { MIGRATE_TYPES }, /* Never used */ #ifdef CONFIG_CMA [MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */ #endif @@ -2795,8 +2795,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone, /* Yoink! */ mt = get_pageblock_migratetype(page); - if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt) - && !is_migrate_cma(mt)) { + /* Only reserve normal pageblocks (i.e., they can merge with others) */ + if (migratetype_is_mergeable(mt)) { zone->nr_reserved_highatomic += pageblock_nr_pages; set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC); move_freepages_block(zone, page, MIGRATE_HIGHATOMIC, NULL); @@ -3545,8 +3545,11 @@ int __isolate_free_page(struct page *page, unsigned int order) struct page *endpage = page + (1 << order) - 1; for (; page < endpage; page += pageblock_nr_pages) { int mt = get_pageblock_migratetype(page); - if (!is_migrate_isolate(mt) && !is_migrate_cma(mt) - && !is_migrate_highatomic(mt)) + /* + * Only change normal pageblocks (i.e., they can merge + * with others) + */ + if (migratetype_is_mergeable(mt)) set_pageblock_migratetype(page, MIGRATE_MOVABLE); }