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Message-Id: <20121207142614.428b8a54.akpm@linux-foundation.org>
Date: Fri, 7 Dec 2012 14:26:14 -0800
From: Andrew Morton <akpm@...ux-foundation.org>
To: Dave Hansen <dave@...ux.vnet.ibm.com>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Debugging: Keep track of page owners
On Fri, 07 Dec 2012 16:24:17 -0500
Dave Hansen <dave@...ux.vnet.ibm.com> wrote:
> To: akpm@...l.org
It's years since I was called that.
> From: mel@...net.ie (Mel Gorman)
And him that.
I have cunningly divined the intention of your update and have queued
the below incremental. The change to
pagetypeinfo_showmixedcount_print() was a surprise. What's that there
for?
From: Dave Hansen <dave@...ux.vnet.ibm.com>
Subject: debugging-keep-track-of-page-owners-fix
Use linux/stacktrace.h rather than hand-coding the stack tracing
Signed-off-by: Dave Hansen <dave@...ux.vnet.ibm.com>
Cc: Mel Gorman <mel@....ul.ie>
Cc: Andy Whitcroft <apw@...dowen.org>
Cc: Mel Gorman <mel@....ul.ie>
Cc: Christoph Lameter <cl@...ux-foundation.org>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Laura Abbott <lauraa@...eaurora.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
include/linux/mm_types.h | 4 +-
include/linux/stacktrace.h | 3 +
kernel/stacktrace.c | 23 ++++++++++++
lib/Kconfig.debug | 1
mm/page_alloc.c | 65 ++++-------------------------------
mm/pageowner.c | 27 ++++----------
mm/vmstat.c | 5 ++
7 files changed, 51 insertions(+), 77 deletions(-)
diff -puN include/linux/mm_types.h~debugging-keep-track-of-page-owners-fix include/linux/mm_types.h
--- a/include/linux/mm_types.h~debugging-keep-track-of-page-owners-fix
+++ a/include/linux/mm_types.h
@@ -8,6 +8,7 @@
#include <linux/spinlock.h>
#include <linux/rbtree.h>
#include <linux/rwsem.h>
+#include <linux/stacktrace.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
#include <linux/page-debug-flags.h>
@@ -180,7 +181,8 @@ struct page {
#ifdef CONFIG_PAGE_OWNER
int order;
unsigned int gfp_mask;
- unsigned long trace[8];
+ struct stack_trace trace;
+ unsigned long trace_entries[8];
#endif
}
/*
diff -puN include/linux/stacktrace.h~debugging-keep-track-of-page-owners-fix include/linux/stacktrace.h
--- a/include/linux/stacktrace.h~debugging-keep-track-of-page-owners-fix
+++ a/include/linux/stacktrace.h
@@ -20,6 +20,8 @@ extern void save_stack_trace_tsk(struct
struct stack_trace *trace);
extern void print_stack_trace(struct stack_trace *trace, int spaces);
+extern int snprint_stack_trace(char *buf, int buf_len,
+ struct stack_trace *trace, int spaces);
#ifdef CONFIG_USER_STACKTRACE_SUPPORT
extern void save_stack_trace_user(struct stack_trace *trace);
@@ -32,6 +34,7 @@ extern void save_stack_trace_user(struct
# define save_stack_trace_tsk(tsk, trace) do { } while (0)
# define save_stack_trace_user(trace) do { } while (0)
# define print_stack_trace(trace, spaces) do { } while (0)
+# define snprint_stack_trace(buf, len, trace, spaces) do { } while (0)
#endif
#endif
diff -puN kernel/stacktrace.c~debugging-keep-track-of-page-owners-fix kernel/stacktrace.c
--- a/kernel/stacktrace.c~debugging-keep-track-of-page-owners-fix
+++ a/kernel/stacktrace.c
@@ -11,6 +11,29 @@
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
+int snprint_stack_trace(char *buf, int buf_len, struct stack_trace *trace,
+ int spaces)
+{
+ int ret = 0;
+ int i;
+
+ if (WARN_ON(!trace->entries))
+ return 0;
+
+ for (i = 0; i < trace->nr_entries; i++) {
+ unsigned long ip = trace->entries[i];
+ int printed = snprintf(buf, buf_len, "%*c[<%p>] %pS\n",
+ 1 + spaces, ' ',
+ (void *) ip, (void *) ip);
+ buf_len -= printed;
+ ret += printed;
+ buf += printed;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(snprint_stack_trace);
+
void print_stack_trace(struct stack_trace *trace, int spaces)
{
int i;
diff -puN lib/Kconfig.debug~debugging-keep-track-of-page-owners-fix lib/Kconfig.debug
--- a/lib/Kconfig.debug~debugging-keep-track-of-page-owners-fix
+++ a/lib/Kconfig.debug
@@ -103,6 +103,7 @@ config PAGE_OWNER
bool "Track page owner"
depends on DEBUG_KERNEL
select DEBUG_FS
+ select STACKTRACE
help
This keeps track of what call chain is the owner of a page, may
help to find bare alloc_page(s) leaks. Eats a fair amount of memory.
diff -puN mm/page_alloc.c~debugging-keep-track-of-page-owners-fix mm/page_alloc.c
--- a/mm/page_alloc.c~debugging-keep-track-of-page-owners-fix
+++ a/mm/page_alloc.c
@@ -2267,62 +2267,21 @@ __perform_reclaim(gfp_t gfp_mask, unsign
return progress;
}
-#ifdef CONFIG_PAGE_OWNER
-static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
-{
- return p > (void *)tinfo &&
- p < (void *)tinfo + THREAD_SIZE - 3;
-}
-
-static inline void __stack_trace(struct page *page, unsigned long *stack,
- unsigned long bp)
-{
- int i = 0;
- unsigned long addr;
- struct thread_info *tinfo = (struct thread_info *)
- ((unsigned long)stack & (~(THREAD_SIZE - 1)));
-
- memset(page->trace, 0, sizeof(long) * 8);
-
-#ifdef CONFIG_FRAME_POINTER
- if (bp) {
- while (valid_stack_ptr(tinfo, (void *)bp)) {
- addr = *(unsigned long *)(bp + sizeof(long));
- page->trace[i] = addr;
- if (++i >= 8)
- break;
- bp = *(unsigned long *)bp;
- }
- return;
- }
-#endif /* CONFIG_FRAME_POINTER */
- while (valid_stack_ptr(tinfo, stack)) {
- addr = *stack++;
- if (__kernel_text_address(addr)) {
- page->trace[i] = addr;
- if (++i >= 8)
- break;
- }
- }
-}
-
static void set_page_owner(struct page *page, unsigned int order,
unsigned int gfp_mask)
{
- unsigned long address;
- unsigned long bp = 0;
-#ifdef CONFIG_X86_64
- asm ("movq %%rbp, %0" : "=r" (bp) : );
-#endif
-#ifdef CONFIG_X86_32
- asm ("movl %%ebp, %0" : "=r" (bp) : );
-#endif
+#ifdef CONFIG_PAGE_OWNER
+ struct stack_trace *trace = &page->trace;
+ trace->nr_entries = 0;
+ trace->max_entries = ARRAY_SIZE(page->trace_entries);
+ trace->entries = &page->trace_entries[0];
+ trace->skip = 3;
+ save_stack_trace(&page->trace);
+
page->order = (int) order;
page->gfp_mask = gfp_mask;
- __stack_trace(page, &address, bp);
-}
#endif /* CONFIG_PAGE_OWNER */
-
+}
/* The really slow allocator path where we enter direct reclaim */
static inline struct page *
@@ -2359,10 +2318,8 @@ retry:
goto retry;
}
-#ifdef CONFIG_PAGE_OWNER
if (page)
set_page_owner(page, order, gfp_mask);
-#endif
return page;
}
@@ -2672,10 +2629,8 @@ nopage:
warn_alloc_failed(gfp_mask, order, NULL);
return page;
got_pg:
-#ifdef CONFIG_PAGE_OWNER
if (page)
set_page_owner(page, order, gfp_mask);
-#endif
if (kmemcheck_enabled)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);
@@ -2758,10 +2713,8 @@ out:
memcg_kmem_commit_charge(page, memcg, order);
-#ifdef CONFIG_PAGE_OWNER
if (page)
set_page_owner(page, order, gfp_mask);
-#endif
return page;
}
diff -puN mm/pageowner.c~debugging-keep-track-of-page-owners-fix mm/pageowner.c
--- a/mm/pageowner.c~debugging-keep-track-of-page-owners-fix
+++ a/mm/pageowner.c
@@ -26,12 +26,8 @@ read_page_owner(struct file *file, char
{
unsigned long pfn;
struct page *page;
- char *kbuf, *modname;
- const char *symname;
+ char *kbuf;
int ret = 0;
- char namebuf[128];
- unsigned long offset = 0, symsize;
- int i;
ssize_t num_written = 0;
int blocktype = 0, pagetype = 0;
@@ -67,7 +63,7 @@ read_page_owner(struct file *file, char
pfn);
/* Stop search if page is allocated and has trace info */
- if (page->order >= 0 && page->trace[0]) {
+ if (page->order >= 0 && page->trace.nr_entries) {
//intk("stopped search at pfn: %ld\n", pfn);
break;
}
@@ -126,20 +122,13 @@ read_page_owner(struct file *file, char
num_written = ret;
- for (i = 0; i < 8; i++) {
- if (!page->trace[i])
- break;
- symname = kallsyms_lookup(page->trace[i], &symsize, &offset,
- &modname, namebuf);
- ret = snprintf(kbuf + num_written, count - num_written,
- "[0x%lx] %s+%lu\n",
- page->trace[i], namebuf, offset);
- if (ret >= count - num_written) {
- ret = -ENOMEM;
- goto out;
- }
- num_written += ret;
+ ret = snprint_stack_trace(kbuf + num_written, count - num_written,
+ &page->trace, 0);
+ if (ret >= count - num_written) {
+ ret = -ENOMEM;
+ goto out;
}
+ num_written += ret;
ret = snprintf(kbuf + num_written, count - num_written, "\n");
if (ret >= count - num_written) {
diff -puN mm/vmstat.c~debugging-keep-track-of-page-owners-fix mm/vmstat.c
--- a/mm/vmstat.c~debugging-keep-track-of-page-owners-fix
+++ a/mm/vmstat.c
@@ -985,7 +985,10 @@ static void pagetypeinfo_showmixedcount_
pagetype = allocflags_to_migratetype(page->gfp_mask);
if (pagetype != mtype) {
- count[mtype]++;
+ if (is_migrate_cma(pagetype))
+ count[MIGRATE_MOVABLE]++;
+ else
+ count[mtype]++;
break;
}
_
--
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