Commit 36994e58 authored Dec 29, 2008 by Frederic Weisbecker Committed by Ingo Molnar Dec 30, 2008

tracing/kmemtrace: normalize the raw tracer event to the unified tracing API



Impact: new tracer plugin

This patch adapts kmemtrace raw events tracing to the unified tracing API.

To enable and use this tracer, just do the following:

 echo kmemtrace > /debugfs/tracing/current_tracer
 cat /debugfs/tracing/trace

You will have the following output:

 # tracer: kmemtrace
 #
 #
 # ALLOC  TYPE  REQ   GIVEN  FLAGS           POINTER         NODE    CALLER
 # FREE   |      |     |       |              |   |            |        |
 # |

type_id 1 call_site 18446744071565527833 ptr 18446612134395152256
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164672 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345164912 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 0 call_site 18446744071565636711 ptr 18446612134345165152 bytes_req 240 bytes_alloc 240 gfp_flags 208 node -1
type_id 0 call_site 18446744071566144042 ptr 18446612134346191680 bytes_req 1304 bytes_alloc 1312 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584
type_id 0 call_site 18446744071565585597 ptr 18446612134405955584 bytes_req 4096 bytes_alloc 4096 gfp_flags 208 node -1
type_id 1 call_site 18446744071565585534 ptr 18446612134405955584

That was to stay backward compatible with the format output produced in
inux/tracepoint.h.

This is the default ouput, but note that I tried something else.

If you change an option:

echo kmem_minimalistic > /debugfs/trace_options

and then cat /debugfs/trace, you will have the following output:

 # tracer: kmemtrace
 #
 #
 # ALLOC  TYPE  REQ   GIVEN  FLAGS           POINTER         NODE    CALLER
 # FREE   |      |     |       |              |   |            |        |
 # |

   -      C                            0xffff88007c088780          file_free_rcu
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc780     -1   d_alloc
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc870     -1   d_alloc
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   +      K    240    240   000000d0   0xffff8800790dc960     -1   d_alloc
   +      K   1304   1312   000000d0   0xffff8800791d7340     -1   reiserfs_alloc_inode
   -      C                            0xffff88007cad6000          putname
   +      K   4096   4096   000000d0   0xffff88007cad6000     -1   getname
   -      C                            0xffff88007cad6000          putname
   +      K    992   1000   000000d0   0xffff880079045b58     -1   alloc_inode
   +      K    768   1024   000080d0   0xffff88007c096400     -1   alloc_pipe_info
   +      K    240    240   000000d0   0xffff8800790dca50     -1   d_alloc
   +      K    272    320   000080d0   0xffff88007c088780     -1   get_empty_filp
   +      K    272    320   000080d0   0xffff88007c088000     -1   get_empty_filp

Yeah I shall confess kmem_minimalistic should be: kmem_alternative.

Whatever, I find it more readable but this a personal opinion of course.
We can drop it if you want.

On the ALLOC/FREE column, + means an allocation and - a free.

On the type column, you have K = kmalloc, C = cache, P = page

I would like the flags to be GFP_* strings but that would not be easy to not
break the column with strings....

About the node...it seems to always be -1. I don't know why but that shouldn't
be difficult to find.

I moved linux/tracepoint.h to trace/tracepoint.h as well. I think that would
be more easy to find the tracer headers if they are all in their common
directory.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 7a51cffb

include/linux/slab_def.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -14,7 +14,7 @@
		#include <asm/page.h> /* kmalloc_sizes.h needs PAGE_SIZE */
		#include <asm/cache.h> /* kmalloc_sizes.h needs L1_CACHE_BYTES */
		#include <linux/compiler.h>
		#include <linux/kmemtrace.h>
		#include <trace/kmemtrace.h>

		/* Size description struct for general caches. */
		struct cache_sizes {

include/linux/slub_def.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -10,7 +10,7 @@
		#include <linux/gfp.h>
		#include <linux/workqueue.h>
		#include <linux/kobject.h>
		#include <linux/kmemtrace.h>
		#include <trace/kmemtrace.h>

		enum stat_item {
		ALLOC_FASTPATH, /* Allocation from cpu slab */

include/linux/kmemtrace.h→include/trace/kmemtrace.h

+4 −15

Original line number	Diff line number	Diff line
		@@ -22,28 +22,17 @@ enum kmemtrace_type_id {

		extern void kmemtrace_init(void);

		static inline void kmemtrace_mark_alloc_node(enum kmemtrace_type_id type_id,
		extern void kmemtrace_mark_alloc_node(enum kmemtrace_type_id type_id,
		unsigned long call_site,
		const void *ptr,
		size_t bytes_req,
		size_t bytes_alloc,
		gfp_t gfp_flags,
		int node)
		{
		trace_mark(kmemtrace_alloc, "type_id %d call_site %lu ptr %lu "
		"bytes_req %lu bytes_alloc %lu gfp_flags %lu node %d",
		type_id, call_site, (unsigned long) ptr,
		(unsigned long) bytes_req, (unsigned long) bytes_alloc,
		(unsigned long) gfp_flags, node);
		}
		int node);

		static inline void kmemtrace_mark_free(enum kmemtrace_type_id type_id,
		extern void kmemtrace_mark_free(enum kmemtrace_type_id type_id,
		unsigned long call_site,
		const void *ptr)
		{
		trace_mark(kmemtrace_free, "type_id %d call_site %lu ptr %lu",
		type_id, call_site, (unsigned long) ptr);
		}
		const void *ptr);

		#else /* CONFIG_KMEMTRACE */

init/main.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -70,7 +70,7 @@
		#include <asm/setup.h>
		#include <asm/sections.h>
		#include <asm/cacheflush.h>
		#include <linux/kmemtrace.h>
		#include <trace/kmemtrace.h>

		#ifdef CONFIG_X86_LOCAL_APIC
		#include <asm/smp.h>

kernel/trace/Kconfig

+22 −0

Original line number	Diff line number	Diff line
		@@ -264,6 +264,28 @@ config HW_BRANCH_TRACER
		This tracer records all branches on the system in a circular
		buffer giving access to the last N branches for each cpu.

		config KMEMTRACE
		bool "Trace SLAB allocations"
		select TRACING
		depends on RELAY
		help
		kmemtrace provides tracing for slab allocator functions, such as
		kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
		data is then fed to the userspace application in order to analyse
		allocation hotspots, internal fragmentation and so on, making it
		possible to see how well an allocator performs, as well as debug
		and profile kernel code.

		This requires an userspace application to use. See
		Documentation/vm/kmemtrace.txt for more information.

		Saying Y will make the kernel somewhat larger and slower. However,
		if you disable kmemtrace at run-time or boot-time, the performance
		impact is minimal (depending on the arch the kernel is built for).

		If unsure, say N.


		config DYNAMIC_FTRACE
		bool "enable/disable ftrace tracepoints dynamically"
		depends on FUNCTION_TRACER