[for-linus][PATCH 4/5] mm, tracing: Print symbol name for call_site in trace events

From: Steven Rostedt
Date: Sun Sep 29 2019 - 16:08:10 EST


From: Changbin Du <changbin.du@xxxxxxxxx>

To improve the readability of raw slab trace points, print the call_site ip
using '%pS'. Then we can grep events with function names.

[002] .... 808.188897: kmem_cache_free: call_site=putname+0x47/0x50 ptr=00000000cef40c80
[002] .... 808.188898: kfree: call_site=security_cred_free+0x42/0x50 ptr=0000000062400820
[002] .... 808.188904: kmem_cache_free: call_site=put_cred_rcu+0x88/0xa0 ptr=0000000058d74ef8
[002] .... 808.188913: kmem_cache_alloc: call_site=prepare_creds+0x26/0x100 ptr=0000000058d74ef8 bytes_req=168 bytes_alloc=576 gfp_flags=GFP_KERNEL
[002] .... 808.188917: kmalloc: call_site=security_prepare_creds+0x77/0xa0 ptr=0000000062400820 bytes_req=8 bytes_alloc=336 gfp_flags=GFP_KERNEL|__GFP_ZERO
[002] .... 808.188920: kmem_cache_alloc: call_site=getname_flags+0x4f/0x1e0 ptr=00000000cef40c80 bytes_req=4096 bytes_alloc=4480 gfp_flags=GFP_KERNEL
[002] .... 808.188925: kmem_cache_free: call_site=putname+0x47/0x50 ptr=00000000cef40c80
[002] .... 808.188926: kfree: call_site=security_cred_free+0x42/0x50 ptr=0000000062400820
[002] .... 808.188931: kmem_cache_free: call_site=put_cred_rcu+0x88/0xa0 ptr=0000000058d74ef8

Link: http://lkml.kernel.org/r/20190914103215.23301-1-changbin.du@xxxxxxxxx

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/trace/events/kmem.h | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index eb57e3037deb..69e8bb8963db 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -35,8 +35,8 @@ DECLARE_EVENT_CLASS(kmem_alloc,
__entry->gfp_flags = gfp_flags;
),

- TP_printk("call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
- __entry->call_site,
+ TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
+ (void *)__entry->call_site,
__entry->ptr,
__entry->bytes_req,
__entry->bytes_alloc,
@@ -131,7 +131,8 @@ DECLARE_EVENT_CLASS(kmem_free,
__entry->ptr = ptr;
),

- TP_printk("call_site=%lx ptr=%p", __entry->call_site, __entry->ptr)
+ TP_printk("call_site=%pS ptr=%p",
+ (void *)__entry->call_site, __entry->ptr)
);

DEFINE_EVENT(kmem_free, kfree,
--
2.20.1