[PATCH v0 2/2] mm: swap: Forced swap entries release under memory pressure

[Lei Liu <liulei.rjpt@vivo.com>]

When there is memory pressure causing OOM, fully reclaim objects from the
global list that have not reached the threshold.

Signed-off-by: Lei Liu <liulei.rjpt@vivo.com>
---
 include/linux/swapfile.h | 1 +
 mm/page_alloc.c          | 4 ++++
 mm/swapfile.c            | 2 +-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/swapfile.h b/include/linux/swapfile.h
index dc43464cd838..04c660aae7a0 100644
--- a/include/linux/swapfile.h
+++ b/include/linux/swapfile.h
@@ -5,6 +5,7 @@
 extern unsigned long generic_max_swapfile_size(void);
 unsigned long arch_max_swapfile_size(void);
 int add_to_swap_gather_cache(struct mm_struct *mm, swp_entry_t entry, int nr);
+void flush_cache_if_needed(bool check_ache_entries);
 
 /* Maximum swapfile size supported for the arch (not inclusive). */
 extern unsigned long swapfile_maximum_size;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d1d037f97c5f..7c5990c24df7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -55,6 +55,7 @@
 #include <linux/delayacct.h>
 #include <linux/cacheinfo.h>
 #include <linux/pgalloc_tag.h>
+#include <linux/swapfile.h>
 #include <asm/div64.h>
 #include "internal.h"
 #include "shuffle.h"
@@ -3967,6 +3968,9 @@ __alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
 
 	*did_some_progress = 0;
 
+	/* flash async swap cache pool */
+	flush_cache_if_needed(false);
+
 	/*
 	 * Acquire the oom lock.  If that fails, somebody else is
 	 * making progress for us.
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 7c69e726b075..26640ec34fc6 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -229,7 +229,7 @@ static void async_release_func(struct work_struct *work)
 	kfree(work);
 }
 
-static void flush_cache_if_needed(bool check_cache_count)
+void flush_cache_if_needed(bool check_cache_count)
 {
 	struct work_struct *release_work;
 
-- 
2.34.1