[lttng-dev] [PATCH lttng-modules] Statedump event for block devices
Mathieu Desnoyers
mathieu.desnoyers at efficios.com
Wed Apr 16 17:05:43 EDT 2014
aaand merged!
Thanks,
Mathieu
----- Original Message -----
> From: "Julien Desfossez" <jdesfossez at efficios.com>
> To: "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>
> Cc: lttng-dev at lists.lttng.org, "Houssem Daoud" <houssemmh at gmail.com>
> Sent: Wednesday, April 16, 2014 4:59:18 PM
> Subject: Re: [lttng-dev] [PATCH lttng-modules] Statedump event for block devices
>
> Tested-by: Julien Desfossez <jdesfossez at efficios.com>
>
> On 14-04-16 04:56 PM, Mathieu Desnoyers wrote:
> > From: Houssem Daoud <houssemmh at gmail.com>
> >
> > [ Edited by Mathieu Desnoyers. ]
> > Signed-off-by: Houssem Daoud <houssemmh at gmail.com>
> > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> > ---
> > README | 2 +
> > .../events/lttng-module/lttng-statedump.h | 16 +++
> > lttng-statedump-impl.c | 46 ++++++++
> > wrapper/genhd.h | 113
> > ++++++++++++++++++++
> > 4 files changed, 177 insertions(+)
> > create mode 100644 wrapper/genhd.h
> >
> > diff --git a/README b/README
> > index 9aa5b93..119bfa8 100644
> > --- a/README
> > +++ b/README
> > @@ -83,6 +83,8 @@ CONFIG_KPROBES:
> > CONFIG_KRETPROBES:
> > Dynamic function entry/return probe.
> > lttng enable-event -k --function ...
> > +CONFIG_KALLSYMS_ALL:
> > + State dump of mapping between block device number and name.
> >
> >
> > * Note about Perf PMU counters support
> > diff --git a/instrumentation/events/lttng-module/lttng-statedump.h
> > b/instrumentation/events/lttng-module/lttng-statedump.h
> > index e4c86d6..efd22d7 100644
> > --- a/instrumentation/events/lttng-module/lttng-statedump.h
> > +++ b/instrumentation/events/lttng-module/lttng-statedump.h
> > @@ -7,6 +7,7 @@
> > #include <linux/tracepoint.h>
> > #include <linux/nsproxy.h>
> > #include <linux/pid_namespace.h>
> > +#include <linux/types.h>
> >
> > TRACE_EVENT(lttng_statedump_start,
> > TP_PROTO(struct lttng_session *session),
> > @@ -141,6 +142,21 @@ TRACE_EVENT(lttng_statedump_network_interface,
> > TP_printk("")
> > )
> >
> > +TRACE_EVENT(lttng_statedump_block_device,
> > + TP_PROTO(struct lttng_session *session,
> > + dev_t dev, const char *diskname),
> > + TP_ARGS(session, dev, diskname),
> > + TP_STRUCT__entry(
> > + __field(dev_t, dev)
> > + __string(diskname, diskname)
> > + ),
> > + TP_fast_assign(
> > + tp_assign(dev, dev)
> > + tp_strcpy(diskname, diskname)
> > + ),
> > + TP_printk("")
> > +)
> > +
> > /* Called with desc->lock held */
> > TRACE_EVENT(lttng_statedump_interrupt,
> > TP_PROTO(struct lttng_session *session,
> > diff --git a/lttng-statedump-impl.c b/lttng-statedump-impl.c
> > index 3e46ca1..e9fe829 100644
> > --- a/lttng-statedump-impl.c
> > +++ b/lttng-statedump-impl.c
> > @@ -45,6 +45,7 @@
> > #include <linux/swap.h>
> > #include <linux/wait.h>
> > #include <linux/mutex.h>
> > +#include <linux/device.h>
> >
> > #include "lttng-events.h"
> > #include "lttng-tracer.h"
> > @@ -54,6 +55,7 @@
> > #include "wrapper/nsproxy.h"
> > #include "wrapper/irq.h"
> > #include "wrapper/tracepoint.h"
> > +#include "wrapper/genhd.h"
> >
> > #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
> > #include <linux/irq.h>
> > @@ -65,6 +67,7 @@
> > #define TRACE_INCLUDE_FILE lttng-statedump
> > #include "instrumentation/events/lttng-module/lttng-statedump.h"
> >
> > +DEFINE_TRACE(lttng_statedump_block_device);
> > DEFINE_TRACE(lttng_statedump_end);
> > DEFINE_TRACE(lttng_statedump_interrupt);
> > DEFINE_TRACE(lttng_statedump_file_descriptor);
> > @@ -115,7 +118,49 @@ enum lttng_process_status {
> > LTTNG_DEAD = 7,
> > };
> >
> > +static
> > +int lttng_enumerate_block_devices(struct lttng_session *session)
> > +{
> > + struct class *ptr_block_class;
> > + struct device_type *ptr_disk_type;
> > + struct class_dev_iter iter;
> > + struct device *dev;
> > +
> > + ptr_block_class = wrapper_get_block_class();
> > + if (!ptr_block_class)
> > + return -ENOSYS;
> > + ptr_disk_type = wrapper_get_disk_type();
> > + if (!ptr_disk_type) {
> > + return -ENOSYS;
> > + }
> > + class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
> > + while ((dev = class_dev_iter_next(&iter))) {
> > + struct disk_part_iter piter;
> > + struct gendisk *disk = dev_to_disk(dev);
> > + struct hd_struct *part;
> > +
> > + disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
> > + while ((part = disk_part_iter_next(&piter))) {
> > + char name_buf[BDEVNAME_SIZE];
> > + char *p;
> > +
> > + p = wrapper_disk_name(disk, part->partno, name_buf);
> > + if (!p) {
> > + disk_part_iter_exit(&piter);
> > + class_dev_iter_exit(&iter);
> > + return -ENOSYS;
> > + }
> > + trace_lttng_statedump_block_device(session,
> > + part_devt(part), name_buf);
> > + }
> > + disk_part_iter_exit(&piter);
> > + }
> > + class_dev_iter_exit(&iter);
> > + return 0;
> > +}
> > +
> > #ifdef CONFIG_INET
> > +
> > static
> > void lttng_enumerate_device(struct lttng_session *session,
> > struct net_device *dev)
> > @@ -397,6 +442,7 @@ int do_lttng_statedump(struct lttng_session *session)
> > /* FIXME lttng_enumerate_vm_maps(session); */
> > lttng_list_interrupts(session);
> > lttng_enumerate_network_ip_interface(session);
> > + lttng_enumerate_block_devices(session);
> >
> > /* TODO lttng_dump_idt_table(session); */
> > /* TODO lttng_dump_softirq_vec(session); */
> > diff --git a/wrapper/genhd.h b/wrapper/genhd.h
> > new file mode 100644
> > index 0000000..5bb390b
> > --- /dev/null
> > +++ b/wrapper/genhd.h
> > @@ -0,0 +1,113 @@
> > +#ifndef _LTTNG_WRAPPER_GENHD_H
> > +#define _LTTNG_WRAPPER_GENHD_H
> > +
> > +/*
> > + * wrapper/genhd.h
> > + *
> > + * wrapper around block layer functions and data structures. Using
> > + * KALLSYMS to get its address when available, else we need to have a
> > + * kernel that exports this function to GPL modules.
> > + *
> > + * Copyright (C) 2011-2014 Mathieu Desnoyers
> > <mathieu.desnoyers at efficios.com>
> > + *
> > + * This library is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; only
> > + * version 2.1 of the License.
> > + *
> > + * This library is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with this library; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> > 02110-1301 USA
> > + */
> > +
> > +#include <linux/genhd.h>
> > +
> > +#ifdef CONFIG_KALLSYMS
> > +
> > +#include <linux/kallsyms.h>
> > +#include "kallsyms.h"
> > +
> > +static inline
> > +char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
> > +{
> > + char *(*disk_name_sym)(struct gendisk *hd, int partno, char *buf);
> > +
> > + disk_name_sym = (void *) kallsyms_lookup_funcptr("disk_name");
> > + if (disk_name_sym) {
> > + return disk_name_sym(hd, partno, buf);
> > + } else {
> > + printk(KERN_WARNING "LTTng: disk_name symbol lookup failed.\n");
> > + return NULL;
> > + }
> > +}
> > +
> > +#else
> > +
> > +static inline
> > +char *wrapper_disk_name(struct gendisk *hd, int partno, char *buf)
> > +{
> > + return disk_name(hd, partno, buf);
> > +}
> > +
> > +#endif
> > +
> > +#ifdef CONFIG_KALLSYMS_ALL
> > +
> > +static inline
> > +struct class *wrapper_get_block_class(void)
> > +{
> > + struct class *ptr_block_class;
> > +
> > + ptr_block_class = (struct class *)
> > kallsyms_lookup_dataptr("block_class");
> > + if (!ptr_block_class) {
> > + printk(KERN_WARNING "LTTng: block_class symbol lookup failed.\n");
> > + return NULL;
> > + }
> > + return ptr_block_class;
> > +}
> > +
> > +static inline
> > +struct device_type *wrapper_get_disk_type(void)
> > +{
> > + struct device_type *ptr_disk_type;
> > +
> > + ptr_disk_type = (struct device_type *)
> > kallsyms_lookup_dataptr("disk_type");
> > + if (!ptr_disk_type) {
> > + printk(KERN_WARNING "LTTng: disk_type symbol lookup failed.\n");
> > + return NULL;
> > + }
> > + return ptr_disk_type;
> > +}
> > +
> > +#else
> > +
> > +static inline
> > +struct class *wrapper_get_block_class(void)
> > +{
> > + /*
> > + * Symbol block_class is not exported.
> > + * TODO: return &block_class;
> > + */
> > + /* Feature currently unavailable without KALLSYMS_ALL */
> > + return NULL;
> > +}
> > +
> > +static inline
> > +struct device_type *wrapper_get_disk_type(void)
> > +{
> > + /*
> > + * Symbol disk_type is not exported.
> > + * TODO: return &disk_type;
> > + */
> > + /* Feature currently unavailable without KALLSYMS_ALL */
> > + return NULL;
> > +}
> > +
> > +#endif
> > +
> > +#endif /* _LTTNG_WRAPPER_GENHD_H */
> >
>
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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