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From: Pasha Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linux-m68k@lists.linux-m68k.org,
	anshuman.khandual@arm.com, willy@infradead.org,
	akpm@linux-foundation.org, william.kucharski@oracle.com,
	mike.kravetz@oracle.com, vbabka@suse.cz, geert@linux-m68k.org,
	schmitzmic@gmail.com, rostedt@goodmis.org, mingo@redhat.com,
	hannes@cmpxchg.org, guro@fb.com, songmuchun@bytedance.com,
	weixugc@google.com, gthelen@google.com
Subject: [RFC 8/8] mm: simplify page_ref_* functions
Date: Tue, 26 Oct 2021 17:38:22 +0000	[thread overview]
Message-ID: <20211026173822.502506-9-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20211026173822.502506-1-pasha.tatashin@soleen.com>

Now, that we are using atomic_return variants to add/sub/inc/dec page
_refcount, it makes sense to combined page_ref_* return and non return
functions.

Also remove some extra trace points for non-return  variants. This
improves the tracability by always recording the new _refcount value
after the modifications has occurred.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
 include/linux/page_ref.h        | 79 +++++++--------------------------
 include/trace/events/page_ref.h | 26 +++--------
 mm/debug_page_ref.c             | 14 ------
 3 files changed, 22 insertions(+), 97 deletions(-)

diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
index 06f5760fcd06..2a91dbc33486 100644
--- a/include/linux/page_ref.h
+++ b/include/linux/page_ref.h
@@ -8,8 +8,6 @@
 #include <linux/tracepoint-defs.h>
 
 DECLARE_TRACEPOINT(page_ref_init);
-DECLARE_TRACEPOINT(page_ref_mod);
-DECLARE_TRACEPOINT(page_ref_mod_and_test);
 DECLARE_TRACEPOINT(page_ref_mod_and_return);
 DECLARE_TRACEPOINT(page_ref_mod_unless);
 DECLARE_TRACEPOINT(page_ref_freeze);
@@ -27,8 +25,6 @@ DECLARE_TRACEPOINT(page_ref_unfreeze);
 #define page_ref_tracepoint_active(t) tracepoint_enabled(t)
 
 extern void __page_ref_init(struct page *page);
-extern void __page_ref_mod(struct page *page, int v);
-extern void __page_ref_mod_and_test(struct page *page, int v, int ret);
 extern void __page_ref_mod_and_return(struct page *page, int v, int ret);
 extern void __page_ref_mod_unless(struct page *page, int v, int u);
 extern void __page_ref_freeze(struct page *page, int v, int ret);
@@ -41,12 +37,6 @@ extern void __page_ref_unfreeze(struct page *page, int v);
 static inline void __page_ref_init(struct page *page)
 {
 }
-static inline void __page_ref_mod(struct page *page, int v)
-{
-}
-static inline void __page_ref_mod_and_test(struct page *page, int v, int ret)
-{
-}
 static inline void __page_ref_mod_and_return(struct page *page, int v, int ret)
 {
 }
@@ -102,26 +92,7 @@ static inline int page_ref_add_return(struct page *page, int nr)
 
 static inline void page_ref_add(struct page *page, int nr)
 {
-	int ret;
-
-	VM_BUG_ON(nr <= 0);
-	ret = atomic_add_return(nr, &page->_refcount);
-	VM_BUG_ON_PAGE(ret <= 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod))
-		__page_ref_mod(page, nr);
-}
-
-static inline void page_ref_sub(struct page *page, int nr)
-{
-	int ret;
-
-	VM_BUG_ON(nr <= 0);
-	ret = atomic_sub_return(nr, &page->_refcount);
-	VM_BUG_ON_PAGE(ret < 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod))
-		__page_ref_mod(page, -nr);
+	page_ref_add_return(page, nr);
 }
 
 static inline int page_ref_sub_return(struct page *page, int nr)
@@ -137,37 +108,14 @@ static inline int page_ref_sub_return(struct page *page, int nr)
 	return ret;
 }
 
-static inline void page_ref_inc(struct page *page)
-{
-	int ret = atomic_inc_return(&page->_refcount);
-
-	VM_BUG_ON_PAGE(ret <= 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod))
-		__page_ref_mod(page, 1);
-}
-
-static inline void page_ref_dec(struct page *page)
+static inline void page_ref_sub(struct page *page, int nr)
 {
-	int ret = atomic_dec_return(&page->_refcount);
-
-	VM_BUG_ON_PAGE(ret < 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod))
-		__page_ref_mod(page, -1);
+	page_ref_sub_return(page, nr);
 }
 
 static inline int page_ref_sub_and_test(struct page *page, int nr)
 {
-	int ret;
-
-	VM_BUG_ON(nr <= 0);
-	ret = atomic_sub_return(nr, &page->_refcount);
-	VM_BUG_ON_PAGE(ret < 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod_and_test))
-		__page_ref_mod_and_test(page, -nr, ret);
-	return ret == 0;
+	return page_ref_sub_return(page, nr) == 0;
 }
 
 static inline int page_ref_inc_return(struct page *page)
@@ -181,15 +129,10 @@ static inline int page_ref_inc_return(struct page *page)
 	return ret;
 }
 
-static inline int page_ref_dec_and_test(struct page *page)
+static inline void page_ref_inc(struct page *page)
 {
-	int ret = atomic_dec_return(&page->_refcount);
 
-	VM_BUG_ON_PAGE(ret < 0, page);
-
-	if (page_ref_tracepoint_active(page_ref_mod_and_test))
-		__page_ref_mod_and_test(page, -1, ret);
-	return ret == 0;
+	page_ref_inc_return(page);
 }
 
 static inline int page_ref_dec_return(struct page *page)
@@ -203,6 +146,16 @@ static inline int page_ref_dec_return(struct page *page)
 	return ret;
 }
 
+static inline void page_ref_dec(struct page *page)
+{
+	page_ref_dec_return(page);
+}
+
+static inline int page_ref_dec_and_test(struct page *page)
+{
+	return page_ref_dec_return(page) == 0;
+}
+
 static inline int page_ref_add_unless(struct page *page, int nr, int u)
 {
 	int ret;
diff --git a/include/trace/events/page_ref.h b/include/trace/events/page_ref.h
index 87551bb1df9e..883d90508ca2 100644
--- a/include/trace/events/page_ref.h
+++ b/include/trace/events/page_ref.h
@@ -49,7 +49,7 @@ DEFINE_EVENT(page_ref_init_template, page_ref_init,
 	TP_ARGS(page)
 );
 
-DECLARE_EVENT_CLASS(page_ref_mod_template,
+DECLARE_EVENT_CLASS(page_ref_unfreeze_template,
 
 	TP_PROTO(struct page *page, int v),
 
@@ -83,14 +83,7 @@ DECLARE_EVENT_CLASS(page_ref_mod_template,
 		__entry->val)
 );
 
-DEFINE_EVENT(page_ref_mod_template, page_ref_mod,
-
-	TP_PROTO(struct page *page, int v),
-
-	TP_ARGS(page, v)
-);
-
-DECLARE_EVENT_CLASS(page_ref_mod_and_test_template,
+DECLARE_EVENT_CLASS(page_ref_mod_template,
 
 	TP_PROTO(struct page *page, int v, int ret),
 
@@ -126,35 +119,28 @@ DECLARE_EVENT_CLASS(page_ref_mod_and_test_template,
 		__entry->val, __entry->ret)
 );
 
-DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_and_test,
-
-	TP_PROTO(struct page *page, int v, int ret),
-
-	TP_ARGS(page, v, ret)
-);
-
-DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_and_return,
+DEFINE_EVENT(page_ref_mod_template, page_ref_mod_and_return,
 
 	TP_PROTO(struct page *page, int v, int ret),
 
 	TP_ARGS(page, v, ret)
 );
 
-DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_mod_unless,
+DEFINE_EVENT(page_ref_mod_template, page_ref_mod_unless,
 
 	TP_PROTO(struct page *page, int v, int ret),
 
 	TP_ARGS(page, v, ret)
 );
 
-DEFINE_EVENT(page_ref_mod_and_test_template, page_ref_freeze,
+DEFINE_EVENT(page_ref_mod_template, page_ref_freeze,
 
 	TP_PROTO(struct page *page, int v, int ret),
 
 	TP_ARGS(page, v, ret)
 );
 
-DEFINE_EVENT(page_ref_mod_template, page_ref_unfreeze,
+DEFINE_EVENT(page_ref_unfreeze_template, page_ref_unfreeze,
 
 	TP_PROTO(struct page *page, int v),
 
diff --git a/mm/debug_page_ref.c b/mm/debug_page_ref.c
index e32149734122..1de9d93cca25 100644
--- a/mm/debug_page_ref.c
+++ b/mm/debug_page_ref.c
@@ -12,20 +12,6 @@ void __page_ref_init(struct page *page)
 EXPORT_SYMBOL(__page_ref_init);
 EXPORT_TRACEPOINT_SYMBOL(page_ref_init);
 
-void __page_ref_mod(struct page *page, int v)
-{
-	trace_page_ref_mod(page, v);
-}
-EXPORT_SYMBOL(__page_ref_mod);
-EXPORT_TRACEPOINT_SYMBOL(page_ref_mod);
-
-void __page_ref_mod_and_test(struct page *page, int v, int ret)
-{
-	trace_page_ref_mod_and_test(page, v, ret);
-}
-EXPORT_SYMBOL(__page_ref_mod_and_test);
-EXPORT_TRACEPOINT_SYMBOL(page_ref_mod_and_test);
-
 void __page_ref_mod_and_return(struct page *page, int v, int ret)
 {
 	trace_page_ref_mod_and_return(page, v, ret);
-- 
2.33.0.1079.g6e70778dc9-goog



  parent reply	other threads:[~2021-10-26 17:38 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-26 17:38 [RFC 0/8] Hardening page _refcount Pasha Tatashin
2021-10-26 17:38 ` [RFC 1/8] mm: add overflow and underflow checks for page->_refcount Pasha Tatashin
2021-10-26 19:48   ` Matthew Wilcox
2021-10-26 21:34     ` Pasha Tatashin
2021-10-27  1:21       ` Pasha Tatashin
2021-10-27  3:04         ` Matthew Wilcox
2021-10-27 18:22           ` Pasha Tatashin
2021-10-27  7:46   ` Muchun Song
2021-10-27 18:22     ` Pasha Tatashin
2021-10-28  4:08       ` Muchun Song
2021-10-26 17:38 ` [RFC 2/8] mm/hugetlb: remove useless set_page_count() Pasha Tatashin
2021-10-26 18:44   ` Mike Kravetz
2021-10-26 18:50     ` Pasha Tatashin
2021-10-26 21:19       ` Mike Kravetz
2021-10-26 17:38 ` [RFC 3/8] mm: Avoid using set_page_count() in set_page_recounted() Pasha Tatashin
2021-10-26 17:53   ` John Hubbard
2021-10-26 18:01     ` John Hubbard
2021-10-26 18:14       ` Pasha Tatashin
2021-10-26 18:21     ` Pasha Tatashin
2021-10-27  5:12       ` John Hubbard
2021-10-27 18:27         ` Pasha Tatashin
2021-10-28  1:20           ` John Hubbard
2021-10-28  1:35             ` John Hubbard
2021-11-01 14:30               ` Pasha Tatashin
2021-11-01 19:35                 ` John Hubbard
2021-11-01 14:22             ` Pasha Tatashin
2021-11-01 19:31               ` John Hubbard
2021-11-01 19:42               ` John Hubbard
2021-10-26 17:38 ` [RFC 4/8] mm: remove set_page_count() from page_frag_alloc_align Pasha Tatashin
2021-10-26 17:38 ` [RFC 5/8] mm: avoid using set_page_count() when pages are freed into allocator Pasha Tatashin
2021-10-26 17:38 ` [RFC 6/8] mm: rename init_page_count() -> page_ref_init() Pasha Tatashin
2021-10-27  6:46   ` Geert Uytterhoeven
2021-10-26 17:38 ` [RFC 7/8] mm: remove set_page_count() Pasha Tatashin
2021-10-26 17:38 ` Pasha Tatashin [this message]
2021-10-26 18:23 ` [RFC 0/8] Hardening page _refcount Matthew Wilcox
2021-10-26 18:30   ` Pasha Tatashin
2021-10-26 20:13     ` Matthew Wilcox
2021-10-26 21:24       ` Pasha Tatashin

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