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-rw-r--r--include/linux/page_ext.h18
-rw-r--r--mm/page_ext.c14
-rw-r--r--mm/page_owner.c1
-rw-r--r--mm/page_table_check.c1
4 files changed, 32 insertions, 2 deletions
diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h
index 22be4582faae..67314f648aeb 100644
--- a/include/linux/page_ext.h
+++ b/include/linux/page_ext.h
@@ -7,15 +7,33 @@
#include <linux/stackdepot.h>
struct pglist_data;
+
+/**
+ * struct page_ext_operations - per page_ext client operations
+ * @offset: Offset to the client's data within page_ext. Offset is returned to
+ * the client by page_ext_init.
+ * @size: The size of the client data within page_ext.
+ * @need: Function that returns true if client requires page_ext.
+ * @init: (optional) Called to initialize client once page_exts are allocated.
+ * @need_shared_flags: True when client is using shared page_ext->flags
+ * field.
+ *
+ * Each Page Extension client must define page_ext_operations in
+ * page_ext_ops array.
+ */
struct page_ext_operations {
size_t offset;
size_t size;
bool (*need)(void);
void (*init)(void);
+ bool need_shared_flags;
};
#ifdef CONFIG_PAGE_EXTENSION
+/*
+ * The page_ext_flags users must set need_shared_flags to true.
+ */
enum page_ext_flags {
PAGE_EXT_OWNER,
PAGE_EXT_OWNER_ALLOCATED,
diff --git a/mm/page_ext.c b/mm/page_ext.c
index 4ee522fd381c..e2c22ffdbb81 100644
--- a/mm/page_ext.c
+++ b/mm/page_ext.c
@@ -71,6 +71,7 @@ static bool need_page_idle(void)
}
static struct page_ext_operations page_idle_ops __initdata = {
.need = need_page_idle,
+ .need_shared_flags = true,
};
#endif
@@ -86,7 +87,7 @@ static struct page_ext_operations *page_ext_ops[] __initdata = {
#endif
};
-unsigned long page_ext_size = sizeof(struct page_ext);
+unsigned long page_ext_size;
static unsigned long total_usage;
static struct page_ext *lookup_page_ext(const struct page *page);
@@ -106,7 +107,16 @@ static bool __init invoke_need_callbacks(void)
bool need = false;
for (i = 0; i < entries; i++) {
- if (page_ext_ops[i]->need && page_ext_ops[i]->need()) {
+ if (page_ext_ops[i]->need()) {
+ if (page_ext_ops[i]->need_shared_flags) {
+ page_ext_size = sizeof(struct page_ext);
+ break;
+ }
+ }
+ }
+
+ for (i = 0; i < entries; i++) {
+ if (page_ext_ops[i]->need()) {
page_ext_ops[i]->offset = page_ext_size;
page_ext_size += page_ext_ops[i]->size;
need = true;
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 2d27f532df4c..f0553bedb39d 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -99,6 +99,7 @@ struct page_ext_operations page_owner_ops = {
.size = sizeof(struct page_owner),
.need = need_page_owner,
.init = init_page_owner,
+ .need_shared_flags = true,
};
static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
diff --git a/mm/page_table_check.c b/mm/page_table_check.c
index 93e633c1d587..25d8610c0042 100644
--- a/mm/page_table_check.c
+++ b/mm/page_table_check.c
@@ -45,6 +45,7 @@ struct page_ext_operations page_table_check_ops = {
.size = sizeof(struct page_table_check),
.need = need_page_table_check,
.init = init_page_table_check,
+ .need_shared_flags = false,
};
static struct page_table_check *get_page_table_check(struct page_ext *page_ext)