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[PATCH v4 4/5] MIPS/Perf-events: Work with the new callchain interface

To: ralf@linux-mips.org, a.p.zijlstra@chello.nl, fweisbec@gmail.com, will.deacon@arm.com
Subject: [PATCH v4 4/5] MIPS/Perf-events: Work with the new callchain interface
From: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Date: Fri, 21 Jan 2011 16:19:20 +0800
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, wuzhangjin@gmail.com, paulus@samba.org, mingo@elte.hu, acme@redhat.com, dengcheng.zhu@gmail.com, matt@console-pimps.org, sshtylyov@mvista.com, ddaney@caviumnetworks.com
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In-reply-to: <1295597961-7565-1-git-send-email-dengcheng.zhu@gmail.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1295597961-7565-1-git-send-email-dengcheng.zhu@gmail.com>
Sender: linux-mips-bounce@linux-mips.org
This is the MIPS part of the following commits by Frederic Weisbecker:

- f72c1a931e311bb7780fee19e41a89ac42cab50e
    perf: Factorize callchain context handling

    Store the kernel and user contexts from the generic layer instead
    of archs, this gathers some repetitive code.

- 56962b4449af34070bb1994621ef4f0265eed4d8
    perf: Generalize some arch callchain code

    - Most archs use one callchain buffer per cpu, except x86 that needs
      to deal with NMIs. Provide a default perf_callchain_buffer()
      implementation that x86 overrides.

    - Centralize all the kernel/user regs handling and invoke new arch
      handlers from there: perf_callchain_user() / perf_callchain_kernel()
      That avoid all the user_mode(), current->mm checks and so...

    - Invert some parameters in perf_callchain_*() helpers: entry to the
      left, regs to the right, following the traditional (dst, src).

- 70791ce9ba68a5921c9905ef05d23f62a90bc10c
    perf: Generalize callchain_store()

    callchain_store() is the same on every archs, inline it in
    perf_event.h and rename it to perf_callchain_store() to avoid
    any collision.

    This removes repetitive code.

- c1a65932fd7216fdc9a0db8bbffe1d47842f862c
    perf: Drop unappropriate tests on arch callchains

    Drop the TASK_RUNNING test on user tasks for callchains as
    this check doesn't seem to make any sense.

    Also remove the tests for !current that is not supposed to
    happen and current->pid as this should be handled at the
    generic level, with exclude_idle attribute.

Changes:
v4 - v3:
o None
v3 - v2:
o Keep all mentioned commits in the form of number + title + original
summary + (MIPS specific info when needed).
v2 - v1:
o None

Reported-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
---
 arch/mips/kernel/perf_event.c |   63 ++++-------------------------------------
 1 files changed, 6 insertions(+), 57 deletions(-)

diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
index 3d55761..8f7d2f8 100644
--- a/arch/mips/kernel/perf_event.c
+++ b/arch/mips/kernel/perf_event.c
@@ -534,21 +534,13 @@ handle_associated_event(struct cpu_hw_events *cpuc,
 #include "perf_event_mipsxx.c"
 
 /* Callchain handling code. */
-static inline void
-callchain_store(struct perf_callchain_entry *entry,
-               u64 ip)
-{
-       if (entry->nr < PERF_MAX_STACK_DEPTH)
-               entry->ip[entry->nr++] = ip;
-}
 
 /*
  * Leave userspace callchain empty for now. When we find a way to trace
  * the user stack callchains, we add here.
  */
-static void
-perf_callchain_user(struct pt_regs *regs,
-                   struct perf_callchain_entry *entry)
+void perf_callchain_user(struct perf_callchain_entry *entry,
+                   struct pt_regs *regs)
 {
 }
 
@@ -561,23 +553,21 @@ static void save_raw_perf_callchain(struct 
perf_callchain_entry *entry,
        while (!kstack_end(sp)) {
                addr = *sp++;
                if (__kernel_text_address(addr)) {
-                       callchain_store(entry, addr);
+                       perf_callchain_store(entry, addr);
                        if (entry->nr >= PERF_MAX_STACK_DEPTH)
                                break;
                }
        }
 }
 
-static void
-perf_callchain_kernel(struct pt_regs *regs,
-                     struct perf_callchain_entry *entry)
+void perf_callchain_kernel(struct perf_callchain_entry *entry,
+                     struct pt_regs *regs)
 {
        unsigned long sp = regs->regs[29];
 #ifdef CONFIG_KALLSYMS
        unsigned long ra = regs->regs[31];
        unsigned long pc = regs->cp0_epc;
 
-       callchain_store(entry, PERF_CONTEXT_KERNEL);
        if (raw_show_trace || !__kernel_text_address(pc)) {
                unsigned long stack_page =
                        (unsigned long)task_stack_page(current);
@@ -587,53 +577,12 @@ perf_callchain_kernel(struct pt_regs *regs,
                return;
        }
        do {
-               callchain_store(entry, pc);
+               perf_callchain_store(entry, pc);
                if (entry->nr >= PERF_MAX_STACK_DEPTH)
                        break;
                pc = unwind_stack(current, &sp, pc, &ra);
        } while (pc);
 #else
-       callchain_store(entry, PERF_CONTEXT_KERNEL);
        save_raw_perf_callchain(entry, sp);
 #endif
 }
-
-static void
-perf_do_callchain(struct pt_regs *regs,
-                 struct perf_callchain_entry *entry)
-{
-       int is_user;
-
-       if (!regs)
-               return;
-
-       is_user = user_mode(regs);
-
-       if (!current || !current->pid)
-               return;
-
-       if (is_user && current->state != TASK_RUNNING)
-               return;
-
-       if (!is_user) {
-               perf_callchain_kernel(regs, entry);
-               if (current->mm)
-                       regs = task_pt_regs(current);
-               else
-                       regs = NULL;
-       }
-       if (regs)
-               perf_callchain_user(regs, entry);
-}
-
-static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
-
-struct perf_callchain_entry *
-perf_callchain(struct pt_regs *regs)
-{
-       struct perf_callchain_entry *entry = &__get_cpu_var(pmc_irq_entry);
-
-       entry->nr = 0;
-       perf_do_callchain(regs, entry);
-       return entry;
-}
-- 
1.7.1


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