mm: Update is_vmalloc_addr to account for vmalloc savings

is_vmalloc_addr currently assumes that all vmalloc addresses
exist between VMALLOC_START and VMALLOC_END. This may not be
the case when interleaving vmalloc and lowmem. Update the
is_vmalloc_addr to properly check for this.

Correspondingly we need to ensure that VMALLOC_TOTAL accounts
for all the vmalloc regions when CONFIG_ENABLE_VMALLOC_SAVING
is enabled.

Change-Id: I5def3d6ae1a4de59ea36f095b8c73649a37b1f36
Signed-off-by: Susheel Khiani <skhiani@codeaurora.org>

1 files changed, 55 insertions, 1 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 5e0abc97d992..b219ccc015d6 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -291,6 +291,57 @@ static unsigned long cached_align;
 
 static unsigned long vmap_area_pcpu_hole;
 
+#ifdef CONFIG_ENABLE_VMALLOC_SAVING
+#define POSSIBLE_VMALLOC_START	PAGE_OFFSET
+
+#define VMALLOC_BITMAP_SIZE	((VMALLOC_END - PAGE_OFFSET) >> \
+					PAGE_SHIFT)
+#define VMALLOC_TO_BIT(addr)	((addr - PAGE_OFFSET) >> PAGE_SHIFT)
+#define BIT_TO_VMALLOC(i)	(PAGE_OFFSET + i * PAGE_SIZE)
+
+unsigned long total_vmalloc_size;
+unsigned long vmalloc_reserved;
+
+DECLARE_BITMAP(possible_areas, VMALLOC_BITMAP_SIZE);
+
+void mark_vmalloc_reserved_area(void *x, unsigned long size)
+{
+	unsigned long addr = (unsigned long)x;
+
+	bitmap_set(possible_areas, VMALLOC_TO_BIT(addr), size >> PAGE_SHIFT);
+	vmalloc_reserved += size;
+}
+
+int is_vmalloc_addr(const void *x)
+{
+	unsigned long addr = (unsigned long)x;
+
+	if (addr < POSSIBLE_VMALLOC_START || addr >= VMALLOC_END)
+		return 0;
+
+	if (test_bit(VMALLOC_TO_BIT(addr), possible_areas))
+		return 0;
+
+	return 1;
+}
+
+static void calc_total_vmalloc_size(void)
+{
+	total_vmalloc_size = VMALLOC_END - POSSIBLE_VMALLOC_START -
+		vmalloc_reserved;
+}
+#else
+int is_vmalloc_addr(const void *x)
+{
+	unsigned long addr = (unsigned long)x;
+
+	return addr >= VMALLOC_START && addr < VMALLOC_END;
+}
+
+static void calc_total_vmalloc_size(void) { }
+#endif
+EXPORT_SYMBOL(is_vmalloc_addr);
+
 static struct vmap_area *__find_vmap_area(unsigned long addr)
 {
 	struct rb_node *n = vmap_area_root.rb_node;
@@ -1251,7 +1302,7 @@ void __init vmalloc_init(void)
 	}
 
 	vmap_area_pcpu_hole = VMALLOC_END;
-
+	calc_total_vmalloc_size();
 	vmap_initialized = true;
 }
 
@@ -2692,6 +2743,9 @@ static int s_show(struct seq_file *m, void *p)
 	if (v->flags & VM_VPAGES)
 		seq_puts(m, " vpages");
 
+	if (v->flags & VM_LOWMEM)
+		seq_puts(m, " lowmem");
+
 	show_numa_info(m, v);
 	seq_putc(m, '\n');
 	return 0;