Currently the profiling information returns userspace IPs but now way
to correlate them to userspace code. Userspace could look into
/proc/$pid/maps but that might not be current or even present anymore
at the time of analyzing the IPs.
Therefore provide means to track the mmap information and provide it
in the output stream.
XXX: only covers mmap()/munmap(), mremap() and mprotect() are missing.
Signed-off-by: Peter Zijlstra <[email protected]>
---
include/linux/perf_counter.h | 22 ++++++-
kernel/perf_counter.c | 135 +++++++++++++++++++++++++++++++++++++++++++
mm/mmap.c | 10 +++
3 files changed, 166 insertions(+), 1 deletion(-)
Index: linux-2.6/include/linux/perf_counter.h
===================================================================
--- linux-2.6.orig/include/linux/perf_counter.h
+++ linux-2.6/include/linux/perf_counter.h
@@ -137,7 +137,9 @@ struct perf_counter_hw_event {
exclude_kernel : 1, /* ditto kernel */
exclude_hv : 1, /* ditto hypervisor */
exclude_idle : 1, /* don't count when idle */
- include_tid : 1, /* include the tid */
+ include_tid : 1, /* include the tid */
+ mmap : 1, /* include mmap data */
+ munmap : 1, /* include munmap data */
__reserved_1 : 54;
@@ -178,6 +180,9 @@ enum perf_event_type {
PERF_EVENT_IP = 0,
PERF_EVENT_GROUP = 1,
+ PERF_EVENT_MMAP = 2,
+ PERF_EVENT_MUNMAP = 3,
+
__PERF_EVENT_TID = 0x100,
};
@@ -456,6 +461,12 @@ static inline int is_software_counter(st
extern void perf_swcounter_event(u32, u64, int, struct pt_regs *);
+extern void perf_counter_mmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file);
+
+extern void perf_counter_munmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file);
+
#else
static inline void
perf_counter_task_sched_in(struct task_struct *task, int cpu) { }
@@ -475,6 +486,15 @@ static inline int perf_counter_task_enab
static inline void perf_swcounter_event(u32 event, u64 nr,
int nmi, struct pt_regs *regs) { }
+
+static inline void perf_counter_mmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file)
+{ }
+
+static inline void perf_counter_munmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file)
+{ }
+
#endif
#endif /* __KERNEL__ */
Index: linux-2.6/kernel/perf_counter.c
===================================================================
--- linux-2.6.orig/kernel/perf_counter.c
+++ linux-2.6/kernel/perf_counter.c
@@ -25,6 +25,7 @@
#include <linux/anon_inodes.h>
#include <linux/kernel_stat.h>
#include <linux/perf_counter.h>
+#include <linux/dcache.h>
#include <asm/irq_regs.h>
@@ -1778,6 +1779,140 @@ void perf_counter_output(struct perf_cou
}
/*
+ * mmap tracking
+ */
+
+struct perf_mmap_event {
+ struct file *file;
+ char *file_name;
+ int file_size;
+
+ struct {
+ struct perf_event_header header;
+
+ u32 pid;
+ u32 tid;
+ u64 start;
+ u64 len;
+ u64 pgoff;
+ } event;
+};
+
+static void perf_counter_mmap_output(struct perf_counter *counter,
+ struct perf_mmap_event *mmap_event)
+{
+ struct perf_output_handle handle;
+ int size = mmap_event->event.header.size;
+ int ret = perf_output_begin(&handle, counter, size);
+
+ if (ret)
+ return;
+
+ perf_output_put(&handle, mmap_event->event);
+ perf_output_copy(&handle, mmap_event->file_name,
+ mmap_event->file_size);
+ perf_output_end(&handle, 0);
+}
+
+static int perf_counter_mmap_match(struct perf_counter *counter,
+ struct perf_mmap_event *mmap_event)
+{
+ if (counter->hw_event.mmap &&
+ mmap_event->event.header.type == PERF_EVENT_MMAP)
+ return 1;
+
+ if (counter->hw_event.munmap &&
+ mmap_event->event.header.type == PERF_EVENT_MUNMAP)
+ return 1;
+
+ return 0;
+}
+
+static void perf_counter_mmap_ctx(struct perf_counter_context *ctx,
+ struct perf_mmap_event *mmap_event)
+{
+ struct perf_counter *counter;
+
+ if (system_state != SYSTEM_RUNNING || list_empty(&ctx->event_list))
+ return;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(counter, &ctx->event_list, event_entry) {
+ if (perf_counter_mmap_match(counter, mmap_event))
+ perf_counter_mmap_output(counter, mmap_event);
+ }
+ rcu_read_unlock();
+}
+
+static void perf_counter_mmap_event(struct perf_mmap_event *mmap_event)
+{
+ struct perf_cpu_context *cpuctx;
+ struct file *file = mmap_event->file;
+ unsigned int size;
+ char *buf = NULL;
+ char *name;
+
+ if (file) {
+ name = kzalloc(PATH_MAX, GFP_KERNEL);
+ name = dentry_path(file->f_dentry, name, PATH_MAX);
+ if (IS_ERR(name))
+ name = "//toolong\0\0\0\0\0\0\0";
+ } else
+ name = "//anon\0\0";
+
+ size = ALIGN(strlen(name), sizeof(u64));
+
+ mmap_event->file_name = name;
+ mmap_event->file_size = size;
+
+ mmap_event->event.header.size = sizeof(mmap_event->event) + size;
+
+ cpuctx = &get_cpu_var(perf_cpu_context);
+ perf_counter_mmap_ctx(&cpuctx->ctx, mmap_event);
+ put_cpu_var(perf_cpu_context);
+
+ perf_counter_mmap_ctx(¤t->perf_counter_ctx, mmap_event);
+
+ kfree(buf);
+}
+
+void perf_counter_mmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file)
+{
+ struct perf_mmap_event mmap_event = {
+ .file = file,
+ .event = {
+ .header = { .type = PERF_EVENT_MMAP, },
+ .pid = current->group_leader->pid,
+ .tid = current->pid,
+ .start = addr,
+ .len = len,
+ .pgoff = pgoff,
+ },
+ };
+
+ perf_counter_mmap_event(&mmap_event);
+}
+
+void perf_counter_munmap(unsigned long addr, unsigned long len,
+ unsigned long pgoff, struct file *file)
+{
+ struct perf_mmap_event mmap_event = {
+ .file = file,
+ .event = {
+ .header = { .type = PERF_EVENT_MUNMAP, },
+ .pid = current->group_leader->pid,
+ .tid = current->pid,
+ .start = addr,
+ .len = len,
+ .pgoff = pgoff,
+ },
+ };
+
+ perf_counter_mmap_event(&mmap_event);
+}
+
+/*
* Generic software counter infrastructure
*/
Index: linux-2.6/mm/mmap.c
===================================================================
--- linux-2.6.orig/mm/mmap.c
+++ linux-2.6/mm/mmap.c
@@ -27,6 +27,7 @@
#include <linux/mempolicy.h>
#include <linux/rmap.h>
#include <linux/mmu_notifier.h>
+#include <linux/perf_counter.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
@@ -1219,6 +1220,9 @@ munmap_back:
if (correct_wcount)
atomic_inc(&inode->i_writecount);
out:
+ if (vm_flags & VM_EXEC)
+ perf_counter_mmap(addr, len, pgoff, file);
+
mm->total_vm += len >> PAGE_SHIFT;
vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
if (vm_flags & VM_LOCKED) {
@@ -1752,6 +1756,12 @@ static void remove_vma_list(struct mm_st
do {
long nrpages = vma_pages(vma);
+ if (vma->vm_flags & VM_EXEC) {
+ perf_counter_munmap(vma->vm_start,
+ nrpages << PAGE_SIZE,
+ vma->vm_pgoff, vma->vm_file);
+ }
+
mm->total_vm -= nrpages;
vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
vma = remove_vma(vma);
--
Peter Zijlstra writes:
> --- linux-2.6.orig/include/linux/perf_counter.h
> +++ linux-2.6/include/linux/perf_counter.h
> @@ -137,7 +137,9 @@ struct perf_counter_hw_event {
> exclude_kernel : 1, /* ditto kernel */
> exclude_hv : 1, /* ditto hypervisor */
> exclude_idle : 1, /* don't count when idle */
> - include_tid : 1, /* include the tid */
> + include_tid : 1, /* include the tid */
> + mmap : 1, /* include mmap data */
> + munmap : 1, /* include munmap data */
>
> __reserved_1 : 54;
Nit: need to adjust the size of __reserved_1 here. Or maybe just get
rid of it?
Paul.
* Paul Mackerras <[email protected]> wrote:
> Peter Zijlstra writes:
>
> > --- linux-2.6.orig/include/linux/perf_counter.h
> > +++ linux-2.6/include/linux/perf_counter.h
> > @@ -137,7 +137,9 @@ struct perf_counter_hw_event {
> > exclude_kernel : 1, /* ditto kernel */
> > exclude_hv : 1, /* ditto hypervisor */
> > exclude_idle : 1, /* don't count when idle */
> > - include_tid : 1, /* include the tid */
> > + include_tid : 1, /* include the tid */
> > + mmap : 1, /* include mmap data */
> > + munmap : 1, /* include munmap data */
> >
> > __reserved_1 : 54;
>
> Nit: need to adjust the size of __reserved_1 here. Or maybe just
> get rid of it?
it's nice to have a constant reminder about how many bits there are
left.
Ingo
Ingo Molnar writes:
> * Paul Mackerras <[email protected]> wrote:
>
> > Peter Zijlstra writes:
> >
> > > --- linux-2.6.orig/include/linux/perf_counter.h
> > > +++ linux-2.6/include/linux/perf_counter.h
> > > @@ -137,7 +137,9 @@ struct perf_counter_hw_event {
> > > exclude_kernel : 1, /* ditto kernel */
> > > exclude_hv : 1, /* ditto hypervisor */
> > > exclude_idle : 1, /* don't count when idle */
> > > - include_tid : 1, /* include the tid */
> > > + include_tid : 1, /* include the tid */
> > > + mmap : 1, /* include mmap data */
> > > + munmap : 1, /* include munmap data */
> > >
> > > __reserved_1 : 54;
> >
> > Nit: need to adjust the size of __reserved_1 here. Or maybe just
> > get rid of it?
>
> it's nice to have a constant reminder about how many bits there are
> left.
Fair enough, but as it stands, we've changed the ABI, so we need to
fix it.
Paul.
I wrote:
> Fair enough, but as it stands, we've changed the ABI, so we need to
> fix it.
I meant of course that that patch would change the ABI if it were
accepted...
Paul.