Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757004AbZA0UIT (ORCPT ); Tue, 27 Jan 2009 15:08:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755784AbZA0UIJ (ORCPT ); Tue, 27 Jan 2009 15:08:09 -0500 Received: from mga11.intel.com ([192.55.52.93]:26878 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753991AbZA0UII (ORCPT ); Tue, 27 Jan 2009 15:08:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.37,334,1231142400"; d="scan'208";a="660573439" Message-ID: <497F69A4.2070007@intel.com> Date: Tue, 27 Jan 2009 12:08:04 -0800 From: "Kok, Auke" User-Agent: Thunderbird 2.0.0.17 (X11/20081103) MIME-Version: 1.0 To: Linux Kernel Mailing List CC: powertop ml , Arjan van de Ven , Ingo Molnar , srostedt@redhat.com Subject: [PATCH] tracer for sys_open() - sreadahead Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 27 Jan 2009 20:08:04.0919 (UTC) FILETIME=[F6C5A470:01C980BA] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6600 Lines: 256 This tracer monitors regular file open() syscalls. This is a fast and low-overhead alternative to strace, and does not allow or require to be attached to every process. The tracer only logs succesfull calls, as those are the only ones we are currently interested in, and we can determine the absolute path of these files as we log. Signed-off-by: Auke Kok diff --git a/fs/open.c b/fs/open.c index a3a78ce..8cf2a6b 100644 --- a/fs/open.c +++ b/fs/open.c @@ -30,6 +30,10 @@ #include #include +#include + +DEFINE_TRACE(do_sys_open); + int vfs_statfs(struct dentry *dentry, struct kstatfs *buf) { int retval = -ENODEV; @@ -1040,6 +1044,7 @@ long do_sys_open(int dfd, const char __user *filename, int flags, int mode) fsnotify_open(f->f_path.dentry); fd_install(fd, f); } + trace_do_sys_open(f, flags, mode, fd); } putname(tmp); } diff --git a/include/trace/fs.h b/include/trace/fs.h new file mode 100644 index 0000000..870eec2 --- /dev/null +++ b/include/trace/fs.h @@ -0,0 +1,11 @@ +#ifndef _TRACE_FS_H +#define _TRACE_FS_H + +#include +#include + +DECLARE_TRACE(do_sys_open, + TPPROTO(struct file *filp, int flags, int mode, long fd), + TPARGS(filp, flags, mode, fd)); + +#endif diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index e2a4ff6..0400815 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -149,6 +149,15 @@ config CONTEXT_SWITCH_TRACER This tracer gets called from the context switch and records all switching of tasks. +config OPEN_CLOSE_TRACER + bool "Trace open() calls" + depends on DEBUG_KERNEL + select TRACING + select MARKERS + help + This tracer records open() syscalls. These calls are made when + files are accessed on disk. + config BOOT_TRACER bool "Trace boot initcalls" depends on DEBUG_KERNEL diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 349d5a9..25cec6c 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_RING_BUFFER) += ring_buffer.o obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o +obj-$(CONFIG_OPEN_CLOSE_TRACER) += trace_open_close.o obj-$(CONFIG_SYSPROF_TRACER) += trace_sysprof.o obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4d3d381..24c17d2 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -30,6 +30,7 @@ enum trace_type { TRACE_USER_STACK, TRACE_HW_BRANCHES, TRACE_POWER, + TRACE_OPEN, __TRACE_LAST_TYPE }; diff --git a/kernel/trace/trace_open_close.c b/kernel/trace/trace_open_close.c new file mode 100644 index 0000000..4250efc --- /dev/null +++ b/kernel/trace/trace_open_close.c @@ -0,0 +1,148 @@ +/* + * trace open calls + * Copyright (C) 2009 Intel Corporation + * + * Based extensively on trace_sched_switch.c + * Copyright (C) 2007 Steven Rostedt + * + */ + +#include +#include +#include +#include +#include +#include +#include + +#include "trace.h" + + +static struct trace_array *ctx_trace; +static int __read_mostly open_trace_enabled; +static atomic_t open_ref; + +static void probe_do_sys_open(struct file *filp, int flags, int mode, long fd) +{ + char *buf; + char *fname; + + if (!atomic_read(&open_ref)) + return; + + if (!open_trace_enabled) + return; + + buf = kzalloc(PAGE_SIZE, GFP_KERNEL); + if (!buf) + return; + fname = d_path(&filp->f_path, buf, PAGE_SIZE); + + if (IS_ERR(fname)) + goto out; + + ftrace_printk("%s: open(\"%s\", %d, %d) = %ld\n", + current->comm, fname, flags, mode, fd); +out: + kfree(buf); +} + +static void open_trace_reset(struct trace_array *tr) +{ + tr->time_start = ftrace_now(tr->cpu); + tracing_reset_online_cpus(tr); +} + +static int open_trace_register(void) +{ + int ret; + + ret = register_trace_do_sys_open(probe_do_sys_open); + if (ret) { + pr_info("open trace: Could not activate tracepoint" + " probe to do_open\n"); + } + + return ret; +} + +static void open_trace_unregister(void) +{ + unregister_trace_do_sys_open(probe_do_sys_open); +} + +static void open_trace_start(void) +{ + long ref; + + ref = atomic_inc_return(&open_ref); + if (ref == 1) + open_trace_register(); +} + +static void open_trace_stop(void) +{ + long ref; + + ref = atomic_dec_and_test(&open_ref); + if (ref) + open_trace_unregister(); +} + +void open_trace_start_cmdline_record(void) +{ + open_trace_start(); +} + +void open_trace_stop_cmdline_record(void) +{ + open_trace_stop(); +} + +static void open_start_trace(struct trace_array *tr) +{ + open_trace_reset(tr); + open_trace_start_cmdline_record(); + open_trace_enabled = 1; +} + +static void open_stop_trace(struct trace_array *tr) +{ + open_trace_enabled = 0; + open_trace_stop_cmdline_record(); +} + +static int open_trace_init(struct trace_array *tr) +{ + ctx_trace = tr; + + open_start_trace(tr); + return 0; +} + +static void reset_open_trace(struct trace_array *tr) +{ + open_stop_trace(tr); +} + +static struct tracer open_trace __read_mostly = +{ + .name = "open", + .init = open_trace_init, + .reset = reset_open_trace, +}; + +__init static int init_open_trace(void) +{ + int ret = 0; + + if (atomic_read(&open_ref)) + ret = open_trace_register(); + if (ret) { + pr_info("error registering open trace\n"); + return ret; + } + return register_tracer(&open_trace); +} +device_initcall(init_open_trace); + -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/