[RFC 08/11] mm: make ttu's return boolean

Minchan Kim
2017-03-02T06:39:33Z

try_to_unmap returns SWAP_SUCCESS or SWAP_FAIL so it's suitable for
boolean return. This patch changes it.

Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
include/linux/rmap.h | 4 ++--
mm/huge_memory.c | 4 ++--
mm/memory-failure.c | 22 ++++++++++------------
mm/rmap.c | 8 +++-----
mm/vmscan.c | 7 +------
5 files changed, 18 insertions(+), 27 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 3630d4d..6028c38 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -191,7 +191,7 @@ static inline void page_dup_rmap(struct page *page, bool compound)
int page_referenced(struct page *, int is_locked,
struct mem_cgroup *memcg, unsigned long *vm_flags);

-int try_to_unmap(struct page *, enum ttu_flags flags);
+bool try_to_unmap(struct page *, enum ttu_flags flags);

/* Avoid racy checks */
#define PVMW_SYNC (1 << 0)
@@ -281,7 +281,7 @@ static inline int page_referenced(struct page *page, int is_locked,
return 0;
}

-#define try_to_unmap(page, refs) SWAP_FAIL
+#define try_to_unmap(page, refs) false

static inline int page_mkclean(struct page *page)
{
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index fe2ccd4..79ea769 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2106,7 +2106,7 @@ static void freeze_page(struct page *page)
{
enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD;
- int ret;
+ bool ret;

VM_BUG_ON_PAGE(!PageHead(page), page);

@@ -2114,7 +2114,7 @@ static void freeze_page(struct page *page)
ttu_flags |= TTU_MIGRATION;

ret = try_to_unmap(page, ttu_flags);
- VM_BUG_ON_PAGE(ret != SWAP_SUCCESS, page);
+ VM_BUG_ON_PAGE(!ret, page);
}

static void unfreeze_page(struct page *page)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b78d080..75fcbd8 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -321,7 +321,7 @@ static void add_to_kill(struct task_struct *tsk, struct page *p,
* wrong earlier.
*/
static void kill_procs(struct list_head *to_kill, int forcekill, int trapno,
- int fail, struct page *page, unsigned long pfn,
+ bool fail, struct page *page, unsigned long pfn,
int flags)
{
struct to_kill *tk, *next;
@@ -903,13 +903,13 @@ EXPORT_SYMBOL_GPL(get_hwpoison_page);
* Do all that is necessary to remove user space mappings. Unmap
* the pages and send SIGBUS to the processes if the data was dirty.
*/
-static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
+static bool hwpoison_user_mappings(struct page *p, unsigned long pfn,
int trapno, int flags, struct page **hpagep)
{
enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
struct address_space *mapping;
LIST_HEAD(tokill);
- int ret;
+ bool ret;
int kill = 1, forcekill;
struct page *hpage = *hpagep;

@@ -918,20 +918,20 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* other types of pages.
*/
if (PageReserved(p) || PageSlab(p))
- return SWAP_SUCCESS;
+ return true;
if (!(PageLRU(hpage) || PageHuge(p)))
- return SWAP_SUCCESS;
+ return true;

/*
* This check implies we don't kill processes if their pages
* are in the swap cache early. Those are always late kills.
*/
if (!page_mapped(hpage))
- return SWAP_SUCCESS;
+ return true;

if (PageKsm(p)) {
pr_err("Memory failure: %#lx: can't handle KSM pages.\n", pfn);
- return SWAP_FAIL;
+ return false;
}

if (PageSwapCache(p)) {
@@ -971,7 +971,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
collect_procs(hpage, &tokill, flags & MF_ACTION_REQUIRED);

ret = try_to_unmap(hpage, ttu);
- if (ret != SWAP_SUCCESS)
+ if (!ret)
pr_err("Memory failure: %#lx: failed to unmap page (mapcount=%d)\n",
pfn, page_mapcount(hpage));

@@ -986,8 +986,7 @@ static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
* any accesses to the poisoned memory.
*/
forcekill = PageDirty(hpage) || (flags & MF_MUST_KILL);
- kill_procs(&tokill, forcekill, trapno,
- ret != SWAP_SUCCESS, p, pfn, flags);
+ kill_procs(&tokill, forcekill, trapno, !ret , p, pfn, flags);

return ret;
}
@@ -1229,8 +1228,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
* When the raw error page is thp tail page, hpage points to the raw
* page after thp split.
*/
- if (hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)
- != SWAP_SUCCESS) {
+ if (!hwpoison_user_mappings(p, pfn, trapno, flags, &hpage)) {
action_result(pfn, MF_MSG_UNMAP_FAILED, MF_IGNORED);
res = -EBUSY;
goto out;
diff --git a/mm/rmap.c b/mm/rmap.c
index da18f21..01f7832 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1489,12 +1489,10 @@ static int page_mapcount_is_zero(struct page *page)
*
* Tries to remove all the page table entries which are mapping this
* page, used in the pageout path. Caller must hold the page lock.
- * Return values are:
*
- * SWAP_SUCCESS - we succeeded in removing all mappings
- * SWAP_FAIL - the page is unswappable
+ * If unmap is successful, return true. Otherwise, false.
*/
-int try_to_unmap(struct page *page, enum ttu_flags flags)
+bool try_to_unmap(struct page *page, enum ttu_flags flags)
{
struct rmap_walk_control rwc = {
.rmap_one = try_to_unmap_one,
@@ -1519,7 +1517,7 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
else
rmap_walk(page, &rwc);

- return !page_mapcount(page) ? SWAP_SUCCESS: SWAP_FAIL;
+ return !page_mapcount(page) ? true: false;
}

static int page_not_mapped(struct page *page)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 170c61f..e4b74f1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -966,7 +966,6 @@ static unsigned long shrink_page_list(struct list_head *page_list,
int may_enter_fs;
enum page_references references = PAGEREF_RECLAIM_CLEAN;
bool dirty, writeback;
- int ret = SWAP_SUCCESS;

cond_resched();

@@ -1139,13 +1138,9 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* processes. Try to unmap it here.
*/
if (page_mapped(page)) {
- switch (ret = try_to_unmap(page,
- ttu_flags | TTU_BATCH_FLUSH)) {
- case SWAP_FAIL:
+ if (!try_to_unmap(page, ttu_flags | TTU_BATCH_FLUSH)) {
nr_unmap_fail++;
goto activate_locked;
- case SWAP_SUCCESS:
- ; /* try to free the page below */
}
}

--
2.7.4