From: Michal Nazarewicz mina86@mina86.com
Signed-off-by: Michal Nazarewicz mina86@mina86.com
--- include/asm-generic/memory_model.h | 17 ++++++++++++++ include/linux/page-isolation.h | 4 ++- mm/page_alloc.c | 43 +++++++++++++++++++++++++++-------- 3 files changed, 53 insertions(+), 11 deletions(-)
On Wed, 2011-09-21 at 17:19 +0200, Michal Nazarewicz wrote:
I wanted to avoid calling pfn_to_page() each time as it seem fairly expensive in sparsemem and disctontig modes. At the same time, the macro trickery is so that users of sparsemem-vmemmap and flatmem won't have to pay the price.
On Wed, 21 Sep 2011 17:45:59 +0200, Dave Hansen dave@linux.vnet.ibm.com wrote:
Personally, I'd say the (incredibly minuscule) runtime cost is worth the cost of making folks' eyes bleed when they see those macros. I think there are some nicer ways to do it.
Yeah. I wasn't amazed by them either.
Is there a reason you can't logically do? page = pfn_to_page(pfn); for (;;) { if (pfn_to_section_nr(pfn) == pfn_to_section_nr(pfn+1)) page++; else page = pfn_to_page(pfn+1); }
Done. Thanks for the suggestions!
+#define __contig_next_page(page, pageblock_left, pfn, increment) \
- (likely((pageblock_left) -= (increment)) ? (page) + (increment) \
: (((pageblock_left) = pageblock_nr_pages), pfn_to_page(pfn)))+#define __contig_first_page(pageblock_left, pfn) ( \
- ((pageblock_left) = pageblock_nr_pages - \
((pfn) & (pageblock_nr_pages - 1))), \- pfn_to_page(pfn))
+#endif
For the love of Pete, please make those in to functions if you're going to keep them.
That was tricky because they modify pageblock_left. Not relevant now anyways though.
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h index fb2d63f..900da88 100644 --- a/include/asm-generic/memory_model.h +++ b/include/asm-generic/memory_model.h @@ -69,6 +69,23 @@ }) #endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */
+#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) + +/* + * Both PFNs must be from the same zone! If this function returns + * true, pfn_to_page(pfn1) + (pfn2 - pfn1) == pfn_to_page(pfn2). + */ +static inline bool zone_pfn_same_memmap(unsigned long pfn1, unsigned long pfn2) +{ + return pfn_to_section_nr(pfn1) == pfn_to_section_nr(pfn2); +} + +#else + +#define zone_pfn_same_memmap(pfn1, pfn2) (true) + +#endif + #define page_to_pfn __page_to_pfn #define pfn_to_page __pfn_to_page
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h index b2a81fd..003c52f 100644 --- a/include/linux/page-isolation.h +++ b/include/linux/page-isolation.h @@ -46,11 +46,13 @@ static inline void unset_migratetype_isolate(struct page *page) { __unset_migratetype_isolate(page, MIGRATE_MOVABLE); } + +/* The below functions must be run on a range from a single zone. */ extern unsigned long alloc_contig_freed_pages(unsigned long start, unsigned long end, gfp_t flag); extern int alloc_contig_range(unsigned long start, unsigned long end, gfp_t flags, unsigned migratetype); -extern void free_contig_pages(struct page *page, int nr_pages); +extern void free_contig_pages(unsigned long pfn, unsigned nr_pages);
/* * For migration. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 46e78d4..bc200a9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5725,31 +5725,46 @@ unsigned long alloc_contig_freed_pages(unsigned long start, unsigned long end, int order;
VM_BUG_ON(!pfn_valid(start)); - zone = page_zone(pfn_to_page(start)); + page = pfn_to_page(start); + zone = page_zone(page);
spin_lock_irq(&zone->lock);
- page = pfn_to_page(pfn); for (;;) { - VM_BUG_ON(page_count(page) || !PageBuddy(page)); + VM_BUG_ON(!page_count(page) || !PageBuddy(page) || + page_zone(page) != zone); + list_del(&page->lru); order = page_order(page); + count = 1UL << order; zone->free_area[order].nr_free--; rmv_page_order(page); - __mod_zone_page_state(zone, NR_FREE_PAGES, -(1UL << order)); - pfn += 1 << order; + __mod_zone_page_state(zone, NR_FREE_PAGES, -(long)count); + + pfn += count; if (pfn >= end) break; VM_BUG_ON(!pfn_valid(pfn)); - page += 1 << order; + + if (zone_pfn_same_memmap(pfn - count, pfn)) + page += count; + else + page = pfn_to_page(pfn); }
spin_unlock_irq(&zone->lock);
/* After this, pages in the range can be freed one be one */ - page = pfn_to_page(start); - for (count = pfn - start; count; --count, ++page) + count = pfn - start; + pfn = start; + for (page = pfn_to_page(pfn); count; --count) { prep_new_page(page, 0, flag); + ++pfn; + if (likely(zone_pfn_same_memmap(pfn - 1, pfn))) + ++page; + else + page = pfn_to_page(pfn); + }
return pfn; } @@ -5903,10 +5918,18 @@ done: return ret; }
-void free_contig_pages(struct page *page, int nr_pages) +void free_contig_pages(unsigned long pfn, unsigned nr_pages) { - for (; nr_pages; --nr_pages, ++page) + struct page *page = pfn_to_page(pfn); + + while (nr_pages--) { __free_page(page); + ++pfn; + if (likely(zone_pfn_same_memmap(pfn - 1, pfn))) + ++page; + else + page = pfn_to_page(pfn); + } }
#ifdef CONFIG_MEMORY_HOTREMOVE