[PATCH] oprofile: report anonymous region samples

The below patch passes samples from anonymous regions to userspace instead
of just dropping them.  This provides the support needed for reporting
anonymous-region code samples (today: basic accumulated results; later:
Java and other dynamically compiled code).

As this changes the format, an upgrade to the just-released 0.9 release of
the userspace tools is required.

This patch is based upon an earlier one by Will Cohen <wcohen@redhat.com>

Signed-off-by: John Levon <levon@movementarian.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

4 files changed, 29 insertions, 15 deletions

diff --git a/Documentation/Changes b/Documentation/Changes
index 57542bc25ed..b3760075476 100644
--- a/Documentation/Changes
+++ b/Documentation/Changes
@@ -63,7 +63,7 @@ o  PPP                    2.4.0                   # pppd --version
 o  isdn4k-utils           3.1pre1                 # isdnctrl 2>&1|grep version
 o  nfs-utils              1.0.5                   # showmount --version
 o  procps                 3.2.0                   # ps --version
-o  oprofile               0.5.3                   # oprofiled --version
+o  oprofile               0.9                     # oprofiled --version
 
 Kernel compilation
 ==================
diff --git a/Documentation/basic_profiling.txt b/Documentation/basic_profiling.txt
index 65e3dc2d443..8764e9f7082 100644
--- a/Documentation/basic_profiling.txt
+++ b/Documentation/basic_profiling.txt
@@ -27,9 +27,13 @@ dump output	readprofile -m /boot/System.map > captured_profile
 
 Oprofile
 --------
-Get the source (I use 0.8) from http://oprofile.sourceforge.net/
-and add "idle=poll" to the kernel command line
+
+Get the source (see Changes for required version) from
+http://oprofile.sourceforge.net/ and add "idle=poll" to the kernel command
+line.
+
 Configure with CONFIG_PROFILING=y and CONFIG_OPROFILE=y & reboot on new kernel
+
 ./configure --with-kernel-support
 make install
 
@@ -46,7 +50,7 @@ start		opcontrol --start
 stop            opcontrol --stop
 dump output     opreport >  output_file
 
-To only report on the kernel, run opreport /boot/vmlinux > output_file
+To only report on the kernel, run opreport -l /boot/vmlinux > output_file
 
 A reset is needed to clear old statistics, which survive a reboot.
 
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index 745a1418363..531b0731314 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -206,7 +206,7 @@ static inline unsigned long fast_get_dcookie(struct dentry * dentry,
  */
 static unsigned long get_exec_dcookie(struct mm_struct * mm)
 {
-        unsigned long cookie = 0;
+        unsigned long cookie = NO_COOKIE;
         struct vm_area_struct * vma;
  
         if (!mm)
@@ -234,35 +234,42 @@ out:
  */
 static unsigned long lookup_dcookie(struct mm_struct * mm, unsigned long addr, off_t * offset)
 {
-        unsigned long cookie = 0;
+        unsigned long cookie = NO_COOKIE;
         struct vm_area_struct * vma;
 
         for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
  
-                if (!vma->vm_file)
-                        continue;
-
                 if (addr < vma->vm_start || addr >= vma->vm_end)
                         continue;
 
-                cookie = fast_get_dcookie(vma->vm_file->f_dentry,
-                        vma->vm_file->f_vfsmnt);
-                *offset = (vma->vm_pgoff << PAGE_SHIFT) + addr - vma->vm_start; 
+                if (vma->vm_file) {
+                        cookie = fast_get_dcookie(vma->vm_file->f_dentry,
+                                vma->vm_file->f_vfsmnt);
+                        *offset = (vma->vm_pgoff << PAGE_SHIFT) + addr -
+                                vma->vm_start;
+                } else {
+                        /* must be an anonymous map */
+                        *offset = addr;
+                }
+
                 break;
         }
 
+        if (!vma)
+                cookie = INVALID_COOKIE;
+
         return cookie;
 }
 
 
-static unsigned long last_cookie = ~0UL;
+static unsigned long last_cookie = INVALID_COOKIE;
  
 static void add_cpu_switch(int i)
 {
         add_event_entry(ESCAPE_CODE);
         add_event_entry(CPU_SWITCH_CODE);
         add_event_entry(i);
-        last_cookie = ~0UL;
+        last_cookie = INVALID_COOKIE;
 }
 
 static void add_kernel_ctx_switch(unsigned int in_kernel)
@@ -317,7 +324,7 @@ static int add_us_sample(struct mm_struct * mm, struct op_sample * s)
  
         cookie = lookup_dcookie(mm, s->eip, &offset);
  
-        if (!cookie) {
+        if (cookie == INVALID_COOKIE) {
                 atomic_inc(&oprofile_stats.sample_lost_no_mapping);
                 return 0;
         }
diff --git a/drivers/oprofile/event_buffer.h b/drivers/oprofile/event_buffer.h
index 442aaad391e..01802363059 100644
--- a/drivers/oprofile/event_buffer.h
+++ b/drivers/oprofile/event_buffer.h
@@ -35,6 +35,9 @@ void wake_up_buffer_waiter(void);
 #define TRACE_BEGIN_CODE                8
 #define TRACE_END_CODE                  9
  
+#define INVALID_COOKIE ~0UL
+#define NO_COOKIE 0UL
+
 /* add data to the event buffer */
 void add_event_entry(unsigned long data);