Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
---
arch/x86/include/asm/page_types.h | 8 ++++++
arch/x86/kernel/e820.c | 45 +++++++++++++++++++++++++++++++++++++
include/linux/mmzone.h | 6 +++++
mm/memcontrol.c | 21 +++++++++++-----
4 files changed, 73 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
index 1df6621..7ae791f 100644
--- a/arch/x86/include/asm/page_types.h
+++ b/arch/x86/include/asm/page_types.h
@@ -52,6 +52,14 @@ extern void initmem_init(unsigned long start_pfn, unsigned long end_pfn,
int acpi, int k8);
extern void free_initmem(void);
+extern void e820_skip_hole(unsigned long *start_pfn, unsigned long *end_pfn);
+
+#define ARCH_HAVE_PFN_SKIP_HOLE 1
+static inline void pfn_skip_hole(unsigned long *start, unsigned long *end)
+{
+ e820_skip_hole(start, end);
+}
+
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_PAGE_DEFS_H */
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 294f26d..b816706 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -1122,3 +1122,48 @@ void __init memblock_find_dma_reserve(void)
set_dma_reserve(mem_size_pfn - free_size_pfn);
#endif
}
+
+/*
+ * The caller wants to skip pfns that are guaranteed to not be valid
+ * memory. Find a stretch of ram between [start_pfn, end_pfn) and
+ * return its pfn range back through start_pfn and end_pfn.
+ */
+
+void e820_skip_hole(unsigned long *start_pfn, unsigned long *end_pfn)
+{
+ unsigned long start = *start_pfn << PAGE_SHIFT;
+ unsigned long end = *end_pfn << PAGE_SHIFT;
+ int i;
+
+ if (start >= end)
+ goto fail; /* short-circuit e820 checks */
+
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ unsigned long last, addr;
+
+ addr = round_up(ei->addr, PAGE_SIZE);
+ last = round_down(ei->addr + ei->size, PAGE_SIZE);
+
+ if (addr >= end)
+ goto fail; /* We're done, not found */
+ if (last <= start)
+ continue; /* Not at start yet, move on */
+ if (ei->type != E820_RAM)
+ continue; /* Not RAM, move on */
+
+ /*
+ * We've found RAM. If start is in this e820 range, return
+ * it, otherwise return the start of this e820 range.
+ */
+
+ if (addr > start)
+ *start_pfn = addr >> PAGE_SHIFT;
+ if (last < end)
+ *end_pfn = last >> PAGE_SHIFT;
+ return;
+ }
+fail:
+ *start_pfn = *end_pfn;
+ return; /* No luck, return failure */
+}
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 02ecb01..955fd02 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -931,6 +931,12 @@ static inline unsigned long early_pfn_to_nid(unsigned long pfn)
#define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
#define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
+#ifndef ARCH_HAVE_PFN_SKIP_HOLE
+static inline void pfn_skip_hole(unsigned long *start, unsigned long *end)
+{
+}
+#endif
+
#ifdef CONFIG_SPARSEMEM
/*
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 042e266..5bdaa23 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5238,18 +5238,25 @@ static inline void kstaled_scan_page(struct page *page)
static void kstaled_scan_node(pg_data_t *pgdat)
{
unsigned long flags;
- unsigned long start, end, pfn;
+ unsigned long pfn, end;
pgdat_resize_lock(pgdat, &flags);
- start = pgdat->node_start_pfn;
- end = start + pgdat->node_spanned_pages;
+ pfn = pgdat->node_start_pfn;
+ end = pfn + pgdat->node_spanned_pages;
- for (pfn = start; pfn < end; pfn++) {
- if (!pfn_valid(pfn))
- continue;
+ while (pfn < end) {
+ unsigned long contiguous = end;
+
+ /* restrict pfn..contiguous to be a RAM backed range */
+ pfn_skip_hole(&pfn, &contiguous);
- kstaled_scan_page(pfn_to_page(pfn));
+ for (; pfn < contiguous; pfn++) {
+ if (!pfn_valid(pfn))
+ continue;
+
+ kstaled_scan_page(pfn_to_page(pfn));
+ }
}
pgdat_resize_unlock(pgdat, &flags);
--
1.7.3.1
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