Merge tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm

Pull frontswap update from Konrad Rzeszutek Wilk: "Features: - Support exlusive get if backend is capable. Bug-fixes: - Fix compile warnings - Add comments/cleanup doc - Fix wrong if condition" * tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm: frontswap: support exclusive gets if tmem backend is capable mm: frontswap: fix a wrong if condition in frontswap_shrink mm/frontswap: fix uninit'ed variable warning mm/frontswap: cleanup doc and comment error mm: frontswap: remove unneeded headers

Merge tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm
Pull frontswap update from Konrad Rzeszutek Wilk: "Features: - Support exlusive get if backend is capable. Bug-fixes: - Fix compile warnings - Add comments/cleanup doc - Fix wrong if condition" * tag 'stable/for-linus-3.7-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/mm: frontswap: support exclusive gets if tmem backend is capable mm: frontswap: fix a wrong if condition in frontswap_shrink mm/frontswap: fix uninit'ed variable warning mm/frontswap: cleanup doc and comment error mm: frontswap: remove unneeded headers
Linus Torvalds
2 parents 88265322c1 e3483a5f3a
Showing 2 changed files Side-by-side Diff
include/linux/frontswap.h
mm/frontswap.c
@@ -19,6 +19,8 @@
 extern void frontswap_shrink(unsigned long);
 extern unsigned long frontswap_curr_pages(void);
 extern void frontswap_writethrough(bool);
+#define FRONTSWAP_HAS_EXCLUSIVE_GETS
+extern void frontswap_tmem_exclusive_gets(bool);
  
 extern void __frontswap_init(unsigned type);
 extern int __frontswap_store(struct page *page);
@@ -44,6 +44,13 @@
  */
 static bool frontswap_writethrough_enabled __read_mostly;
  
+/*
+ * If enabled, the underlying tmem implementation is capable of doing
+ * exclusive gets, so frontswap_load, on a successful tmem_get must
+ * mark the page as no longer in frontswap AND mark it dirty.
+ */
+static bool frontswap_tmem_exclusive_gets_enabled __read_mostly;
+
 #ifdef CONFIG_DEBUG_FS
 /*
  * Counters available via /sys/kernel/debug/frontswap (if debugfs is
@@ -97,6 +104,15 @@
 EXPORT_SYMBOL(frontswap_writethrough);
  
 /*
+ * Enable/disable frontswap exclusive gets (see above).
+ */
+void frontswap_tmem_exclusive_gets(bool enable)
+{
+	frontswap_tmem_exclusive_gets_enabled = enable;
+}
+EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
+
+/*
  * Called when a swap device is swapon'd.
  */
 void __frontswap_init(unsigned type)
  
@@ -174,8 +190,13 @@
 	BUG_ON(sis == NULL);
 	if (frontswap_test(sis, offset))
 		ret = frontswap_ops.load(type, offset, page);
-	if (ret == 0)
+	if (ret == 0) {
 		inc_frontswap_loads();
+		if (frontswap_tmem_exclusive_gets_enabled) {
+			SetPageDirty(page);
+			frontswap_clear(sis, offset);
+		}
+	}
 	return ret;
 }
 EXPORT_SYMBOL(__frontswap_load);
@@ -263,6 +284,11 @@
 	return ret;
 }
  
+/*
+ * Used to check if it's necessory and feasible to unuse pages.
+ * Return 1 when nothing to do, 0 when need to shink pages,
+ * error code when there is an error.
+ */
 static int __frontswap_shrink(unsigned long target_pages,
 				unsigned long *pages_to_unuse,
 				int *type)
@@ -275,7 +301,7 @@
 	if (total_pages <= target_pages) {
 		/* Nothing to do */
 		*pages_to_unuse = 0;
-		return 0;
+		return 1;
 	}
 	total_pages_to_unuse = total_pages - target_pages;
 	return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
@@ -292,7 +318,7 @@
 void frontswap_shrink(unsigned long target_pages)
 {
 	unsigned long pages_to_unuse = 0;
-	int type, ret;
+	int uninitialized_var(type), ret;
  
 	/*
 	 * we don't want to hold swap_lock while doing a very
@@ -302,7 +328,7 @@
 	spin_lock(&swap_lock);
 	ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
 	spin_unlock(&swap_lock);
-	if (ret == 0 && pages_to_unuse)
+	if (ret == 0)
 		try_to_unuse(type, true, pages_to_unuse);
 	return;
 }
...	...	@@ -19,6 +19,8 @@
19	19	extern void frontswap_shrink(unsigned long);
20	20	extern unsigned long frontswap_curr_pages(void);
21	21	extern void frontswap_writethrough(bool);
	22	+#define FRONTSWAP_HAS_EXCLUSIVE_GETS
	23	+extern void frontswap_tmem_exclusive_gets(bool);
22	24
23	25	extern void __frontswap_init(unsigned type);
24	26	extern int __frontswap_store(struct page *page);
...	...	@@ -44,6 +44,13 @@
44	44	*/
45	45	static bool frontswap_writethrough_enabled __read_mostly;
46	46
	47	+/*
	48	+ * If enabled, the underlying tmem implementation is capable of doing
	49	+ * exclusive gets, so frontswap_load, on a successful tmem_get must
	50	+ * mark the page as no longer in frontswap AND mark it dirty.
	51	+ */
	52	+static bool frontswap_tmem_exclusive_gets_enabled __read_mostly;
	53	+
47	54	#ifdef CONFIG_DEBUG_FS
48	55	/*
49	56	* Counters available via /sys/kernel/debug/frontswap (if debugfs is
...	...	@@ -97,6 +104,15 @@
97	104	EXPORT_SYMBOL(frontswap_writethrough);
98	105
99	106	/*
	107	+ * Enable/disable frontswap exclusive gets (see above).
	108	+ */
	109	+void frontswap_tmem_exclusive_gets(bool enable)
	110	+{
	111	+ frontswap_tmem_exclusive_gets_enabled = enable;
	112	+}
	113	+EXPORT_SYMBOL(frontswap_tmem_exclusive_gets);
	114	+
	115	+/*
100	116	* Called when a swap device is swapon'd.
101	117	*/
102	118	void __frontswap_init(unsigned type)
103	119
...	...	@@ -174,8 +190,13 @@
174	190	BUG_ON(sis == NULL);
175	191	if (frontswap_test(sis, offset))
176	192	ret = frontswap_ops.load(type, offset, page);
177		- if (ret == 0)
	193	+ if (ret == 0) {
178	194	inc_frontswap_loads();
	195	+ if (frontswap_tmem_exclusive_gets_enabled) {
	196	+ SetPageDirty(page);
	197	+ frontswap_clear(sis, offset);
	198	+ }
	199	+ }
179	200	return ret;
180	201	}
181	202	EXPORT_SYMBOL(__frontswap_load);
...	...	@@ -263,6 +284,11 @@
263	284	return ret;
264	285	}
265	286
	287	+/*
	288	+ * Used to check if it's necessory and feasible to unuse pages.
	289	+ * Return 1 when nothing to do, 0 when need to shink pages,
	290	+ * error code when there is an error.
	291	+ */
266	292	static int __frontswap_shrink(unsigned long target_pages,
267	293	unsigned long *pages_to_unuse,
268	294	int *type)
...	...	@@ -275,7 +301,7 @@
275	301	if (total_pages <= target_pages) {
276	302	/* Nothing to do */
277	303	*pages_to_unuse = 0;
278		- return 0;
	304	+ return 1;
279	305	}
280	306	total_pages_to_unuse = total_pages - target_pages;
281	307	return __frontswap_unuse_pages(total_pages_to_unuse, pages_to_unuse, type);
...	...	@@ -292,7 +318,7 @@
292	318	void frontswap_shrink(unsigned long target_pages)
293	319	{
294	320	unsigned long pages_to_unuse = 0;
295		- int type, ret;
	321	+ int uninitialized_var(type), ret;
296	322
297	323	/*
298	324	* we don't want to hold swap_lock while doing a very
...	...	@@ -302,7 +328,7 @@
302	328	spin_lock(&swap_lock);
303	329	ret = __frontswap_shrink(target_pages, &pages_to_unuse, &type);
304	330	spin_unlock(&swap_lock);
305		- if (ret == 0 && pages_to_unuse)
	331	+ if (ret == 0)
306	332	try_to_unuse(type, true, pages_to_unuse);
307	333	return;
308	334	}