Messages in this thread | | | Date | Mon, 18 Jun 2007 10:18:47 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 5/7] Introduce a means of compacting memory within a zone |
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On Mon, 18 Jun 2007, Mel Gorman wrote:
> + /* Isolate free pages. This assumes the block is valid */ > + for (; blockpfn < end_pfn; blockpfn++) { > + struct page *page; > + int isolated, i; > + > + if (!pfn_valid_within(blockpfn)) > + continue; > + > + page = pfn_to_page(blockpfn); > + if (!PageBuddy(page)) > + continue;
The name PageBuddy is getting to be misleading. Maybe rename this to PageFree or so?
> + > + /* Found a free page, break it into order-0 pages */ > + isolated = split_free_page(page); > + total_isolated += isolated; > + for (i = 0; i < isolated; i++) { > + list_add(&page->lru, freelist); > + page++; > + }
Why do you need to break them all up? Easier to coalesce later?
> +/* Returns 1 if the page is within a block suitable for migration to */ > +static int pageblock_migratable(struct page *page) > +{ > + /* If the page is a large free page, then allow migration */ > + if (PageBuddy(page) && page_order(page) >= pageblock_order) > + return 1;
if (PageSlab(page) && page->slab->ops->kick) { migratable slab }
if (page table page) { migratable page table page? }
etc?
> + /* Try isolate the page */ > + if (locked_isolate_lru_page(zone, page, migratelist) == 0) > + isolated++;
Support for other ways of migrating a page?
> +static int compact_zone(struct zone *zone, struct compact_control *cc) > +{ > + int ret = COMPACT_INCOMPLETE; > + > + /* Setup to move all movable pages to the end of the zone */ > + cc->migrate_pfn = zone->zone_start_pfn; > + cc->free_pfn = cc->migrate_pfn + zone->spanned_pages; > + cc->free_pfn &= ~(pageblock_nr_pages-1); > + > + for (; ret == COMPACT_INCOMPLETE; ret = compact_finished(zone, cc)) { > + isolate_migratepages(zone, cc); > + > + if (!cc->nr_migratepages) > + continue; > + > + /* Isolate free pages if necessary */ > + if (cc->nr_freepages < cc->nr_migratepages) > + isolate_freepages(zone, cc); > + > + /* Stop compacting if we cannot get enough free pages */ > + if (cc->nr_freepages < cc->nr_migratepages) > + break; > + > + migrate_pages(&cc->migratepages, compaction_alloc, > + (unsigned long)cc);
You do not need to check the result of migration? Page migration is a best effort that may fail.
Looks good otherwise.
Acked-by: Christoph Lameter <clameter@sgi.com>
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