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Subject[PATCH v2 1/5] mm: page_alloc: remain memblock_next_valid_pfn() when CONFIG_HAVE_ARCH_PFN_VALID is enable
Date
Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
where possible") optimized the loop in memmap_init_zone(). But it causes
possible panic bug. So Daniel Vacek reverted it later.

But memblock_next_valid_pfn is valid when CONFIG_HAVE_ARCH_PFN_VALID is
enabled. And as verified by Eugeniu Rosca, arm can benifit from this
commit. So remain the memblock_next_valid_pfn.

Signed-off-by: Jia He <jia.he@hxt-semitech.com>
---
include/linux/memblock.h | 4 ++++
mm/memblock.c | 29 +++++++++++++++++++++++++++++
mm/page_alloc.c | 11 ++++++++++-
3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 0257aee..efbbe4b 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -203,6 +203,10 @@ void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
i >= 0; __next_mem_pfn_range(&i, nid, p_start, p_end, p_nid))
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */

+#ifdef CONFIG_HAVE_ARCH_PFN_VALID
+unsigned long memblock_next_valid_pfn(unsigned long pfn);
+#endif
+
/**
* for_each_free_mem_range - iterate through free memblock areas
* @i: u64 used as loop variable
diff --git a/mm/memblock.c b/mm/memblock.c
index ba7c878..bea5a9c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1102,6 +1102,35 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
*out_nid = r->nid;
}

+#ifdef CONFIG_HAVE_ARCH_PFN_VALID
+unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn)
+{
+ struct memblock_type *type = &memblock.memory;
+ unsigned int right = type->cnt;
+ unsigned int mid, left = 0;
+ phys_addr_t addr = PFN_PHYS(++pfn);
+
+ do {
+ mid = (right + left) / 2;
+
+ if (addr < type->regions[mid].base)
+ right = mid;
+ else if (addr >= (type->regions[mid].base +
+ type->regions[mid].size))
+ left = mid + 1;
+ else {
+ /* addr is within the region, so pfn is valid */
+ return pfn;
+ }
+ } while (left < right);
+
+ if (right == type->cnt)
+ return -1UL;
+ else
+ return PHYS_PFN(type->regions[right].base);
+}
+#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/
+
/**
* memblock_set_node - set node ID on memblock regions
* @base: base of area to set node ID for
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c19f5ac..2a967f7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5483,8 +5483,17 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
if (context != MEMMAP_EARLY)
goto not_early;

- if (!early_pfn_valid(pfn))
+ if (!early_pfn_valid(pfn)) {
+#if (defined CONFIG_HAVE_MEMBLOCK) && (defined CONFIG_HAVE_ARCH_PFN_VALID)
+ /*
+ * Skip to the pfn preceding the next valid one (or
+ * end_pfn), such that we hit a valid pfn (or end_pfn)
+ * on our next iteration of the loop.
+ */
+ pfn = memblock_next_valid_pfn(pfn) - 1;
+#endif
continue;
+ }
if (!early_pfn_in_nid(pfn, nid))
continue;
if (!update_defer_init(pgdat, pfn, end_pfn, &nr_initialised))
--
2.7.4
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