[PATCH v8 5/6] arm: arm64: introduce pfn_valid_region()
From: Jia He <hidden>
Date: 2018-04-11 07:24:04
Also in:
linux-mm, lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
where possible") optimized the loop in memmap_init_zone(). But there is
still some room for improvement. E.g. in early_pfn_valid(), we can record
the last returned memblock region. If current pfn and last pfn are in the
same memory region, we needn't do the unnecessary binary searches because
memblock_is_nomap is the same result for whole memory region.
Signed-off-by: Jia He <redacted>
---
include/linux/early_pfn.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/include/linux/early_pfn.h b/include/linux/early_pfn.h
index f9e40c3..9609391 100644
--- a/include/linux/early_pfn.h
+++ b/include/linux/early_pfn.h@@ -51,5 +51,29 @@ ulong __init_memblock memblock_next_valid_pfn(ulong pfn) return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); + +int pfn_valid_region(ulong pfn) +{ + ulong start_pfn, end_pfn; + struct memblock_type *type = &memblock.memory; + struct memblock_region *regions = type->regions; + + if (early_region_idx != -1) { + start_pfn = PFN_DOWN(regions[early_region_idx].base); + end_pfn = PFN_DOWN(regions[early_region_idx].base + + regions[early_region_idx].size); + + if (pfn >= start_pfn && pfn < end_pfn) + return !memblock_is_nomap( + ®ions[early_region_idx]); + } + + early_region_idx = memblock_search_pfn_regions(pfn); + if (early_region_idx == -1) + return false; + + return !memblock_is_nomap(®ions[early_region_idx]); +} +EXPORT_SYMBOL(pfn_valid_region); #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/ #endif /*__EARLY_PFN_H*/
--
2.7.4