[PATCH] mm: migrate: Return false instead of -EAGAIN for dummy functions

chengang
2016-09-17T07:25:02Z

From: Chen Gang <gang.chen.5i5j@gmail.com>

For migrate_misplaced_page and migrate_misplaced_transhuge_page, they
are pure Boolean functions and are also used as pure Boolean functions,
but the related dummy functions return -EAGAIN.

Also change their related pure Boolean function numamigrate_isolate_page.

For variable isolated in migrate_misplaced_transhuge_page, it need not
be initialized.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
---
include/linux/migrate.h | 16 ++++++++--------
mm/migrate.c | 24 ++++++++++++------------
2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ae8d475..b5e791d 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -88,34 +88,34 @@ static inline void __ClearPageMovable(struct page *page)

#ifdef CONFIG_NUMA_BALANCING
extern bool pmd_trans_migrating(pmd_t pmd);
-extern int migrate_misplaced_page(struct page *page,
- struct vm_area_struct *vma, int node);
+extern bool migrate_misplaced_page(struct page *page,
+ struct vm_area_struct *vma, int node);
#else
static inline bool pmd_trans_migrating(pmd_t pmd)
{
return false;
}
-static inline int migrate_misplaced_page(struct page *page,
- struct vm_area_struct *vma, int node)
+static inline bool migrate_misplaced_page(struct page *page,
+ struct vm_area_struct *vma, int node)
{
- return -EAGAIN; /* can't migrate now */
+ return false;
}
#endif /* CONFIG_NUMA_BALANCING */

#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
-extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
+extern bool migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
pmd_t *pmd, pmd_t entry,
unsigned long address,
struct page *page, int node);
#else
-static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
+static inline bool migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
pmd_t *pmd, pmd_t entry,
unsigned long address,
struct page *page, int node)
{
- return -EAGAIN;
+ return false;
}
#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/

diff --git a/mm/migrate.c b/mm/migrate.c
index f7ee04a..3cdaa19 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1805,7 +1805,7 @@ static bool numamigrate_update_ratelimit(pg_data_t *pgdat,
return false;
}

-static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
+static bool numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
{
int page_lru;

@@ -1813,10 +1813,10 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)

/* Avoid migrating to a node that is nearly full */
if (!migrate_balanced_pgdat(pgdat, 1UL << compound_order(page)))
- return 0;
+ return false;

if (isolate_lru_page(page))
- return 0;
+ return false;

/*
* migrate_misplaced_transhuge_page() skips page migration's usual
@@ -1827,7 +1827,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
*/
if (PageTransHuge(page) && page_count(page) != 3) {
putback_lru_page(page);
- return 0;
+ return false;
}

page_lru = page_is_file_cache(page);
@@ -1840,7 +1840,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
* disappearing underneath us during migration.
*/
put_page(page);
- return 1;
+ return true;
}

bool pmd_trans_migrating(pmd_t pmd)
@@ -1854,11 +1854,11 @@ bool pmd_trans_migrating(pmd_t pmd)
* node. Caller is expected to have an elevated reference count on
* the page that will be dropped by this function before returning.
*/
-int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
+bool migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
int node)
{
pg_data_t *pgdat = NODE_DATA(node);
- int isolated;
+ bool isolated;
int nr_remaining;
LIST_HEAD(migratepages);

@@ -1893,7 +1893,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
page_is_file_cache(page));
putback_lru_page(page);
}
- isolated = 0;
+ isolated = false;
} else
count_vm_numa_event(NUMA_PAGE_MIGRATE);
BUG_ON(!list_empty(&migratepages));
@@ -1901,7 +1901,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,

out:
put_page(page);
- return 0;
+ return false;
}
#endif /* CONFIG_NUMA_BALANCING */

@@ -1910,7 +1910,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
* Migrates a THP to a given target node. page must be locked and is unlocked
* before returning.
*/
-int migrate_misplaced_transhuge_page(struct mm_struct *mm,
+bool migrate_misplaced_transhuge_page(struct mm_struct *mm,
struct vm_area_struct *vma,
pmd_t *pmd, pmd_t entry,
unsigned long address,
@@ -1918,7 +1918,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
{
spinlock_t *ptl;
pg_data_t *pgdat = NODE_DATA(node);
- int isolated = 0;
+ bool isolated;
struct page *new_page = NULL;
int page_lru = page_is_file_cache(page);
unsigned long mmun_start = address & HPAGE_PMD_MASK;
@@ -2052,7 +2052,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
out_unlock:
unlock_page(page);
put_page(page);
- return 0;
+ return false;
}
#endif /* CONFIG_NUMA_BALANCING */

--
1.9.3