Thread (16 messages) flat view 16 messages, 4 authors, 2016-02-19

Re: [PATCH 2/2] mm/page_ref: add tracepoint to track down page reference manipulation

From: Sergey Senozhatsky <hidden>
Date: 2016-02-15 05:07:45
Also in: linux-api, lkml

Hello Joonsoo,

On (02/15/16 12:04), js1304@gmail.com wrote:
[..]
<...>-9018  [004]    92.678375: page_ref_set:         pfn=0x17ac9 flags=0x0 count=1 mapcount=0 mapping=(nil) mt=4 val=1
<...>-9018  [004]    92.678378: kernel_stack:
 => get_page_from_freelist (ffffffff81176659)
 => __alloc_pages_nodemask (ffffffff81176d22)
 => alloc_pages_vma (ffffffff811bf675)
 => handle_mm_fault (ffffffff8119e693)
 => __do_page_fault (ffffffff810631ea)
 => trace_do_page_fault (ffffffff81063543)
 => do_async_page_fault (ffffffff8105c40a)
 => async_page_fault (ffffffff817581d8)
[snip]
<...>-9018  [004]    92.678379: page_ref_mod:         pfn=0x17ac9 flags=0x40048 count=2 mapcount=1 mapping=0xffff880015a78dc1 mt=4 val=1
[snip]
[..]
o Print human-readable page flag through show_page_flags()
not even a nitpick, just for note, the examples don't use show_page_flags().


[..]
quoted hunk ↗ jump to hunk
diff --git a/include/linux/page_ref.h b/include/linux/page_ref.h
index 534249c..fd6d9a5 100644
--- a/include/linux/page_ref.h
+++ b/include/linux/page_ref.h
@@ -1,6 +1,54 @@
 #include <linux/atomic.h>
 #include <linux/mm_types.h>
 #include <linux/page-flags.h>
will this compile with !CONFIG_TRACEPOINTS config?

+#ifdef CONFIG_TRACEPOINTS
 #include <linux/tracepoint-defs.h>

 extern struct tracepoint __tracepoint_page_ref_set;
 extern struct tracepoint __tracepoint_page_ref_mod;
 extern struct tracepoint __tracepoint_page_ref_mod_and_test;
 extern struct tracepoint __tracepoint_page_ref_mod_and_return;
 extern struct tracepoint __tracepoint_page_ref_mod_unless;
 extern struct tracepoint __tracepoint_page_ref_freeze;
 extern struct tracepoint __tracepoint_page_ref_unfreeze;

 #ifdef CONFIG_DEBUG_PAGE_REF
 #define page_ref_tracepoint_active(t) static_key_false(&(t).key)

 extern void __page_ref_set(struct page *page, int v);
 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);
 extern void __page_ref_unfreeze(struct page *page, int v);

 #else

 #define page_ref_tracepoint_active(t) false

 static inline void __page_ref_set(struct page *page, int v)
 {
 }
 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)
 {
 }
 static inline void __page_ref_mod_unless(struct page *page, int v, int u)
 {
 }
 static inline void __page_ref_freeze(struct page *page, int v, int ret)
 {
 }
 static inline void __page_ref_unfreeze(struct page *page, int v)
 {
 }

 #endif /* CONFIG_DEBUG_PAGE_REF */

+#endif /* CONFIG_TRACEPOINTS */

	-ss

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