Re: [Patch 11/11] ftrace plugin for kernel symbol tracing using HWBreakpoint interfaces - v3

From: Steven Rostedt
Date: Wed Mar 25 2009 - 09:24:44 EST



On Wed, 25 Mar 2009, K.Prasad wrote:

> On Tue, Mar 24, 2009 at 08:58:11PM +0530, K.Prasad wrote:
> > This patch adds an ftrace plugin to detect and profile memory access over
> > kernel variables. It uses HW Breakpoint interfaces to 'watch memory
> > addresses.
> >
> > Signed-off-by: K.Prasad <prasad@xxxxxxxxxxxxxxxxxx>
> > ---
> > kernel/trace/Kconfig | 21 +
> > kernel/trace/Makefile | 1
> > kernel/trace/trace.h | 25 +
> > kernel/trace/trace_ksym.c | 555 ++++++++++++++++++++++++++++++++++++++++++
> > kernel/trace/trace_selftest.c | 36 ++
> > 5 files changed, 638 insertions(+)
> >
>
> Submitting the revised patch 11/11 and not reposting the entire
> patchset.
>
> Changelog
> ---------
> - Checking for the appropriate tracer type in the .print_line handler function
>
> Please find the new patch below.
>
> Thanks,
> K.Prasad
>
>
> ftrace plugin for kernel symbol tracing using HW Breakpoint interfaces - v2
>
> This patch adds an ftrace plugin to detect and profile memory access over
> kernel variables. It uses HW Breakpoint interfaces to 'watch memory
> addresses.
>
> Signed-off-by: K.Prasad <prasad@xxxxxxxxxxxxxxxxxx>
> ---
> kernel/trace/Kconfig | 21 +
> kernel/trace/Makefile | 1
> kernel/trace/trace.h | 25 +
> kernel/trace/trace_ksym.c | 558 ++++++++++++++++++++++++++++++++++++++++++
> kernel/trace/trace_selftest.c | 36 ++
> 5 files changed, 641 insertions(+)
>
> +static enum print_line_t ksym_trace_output(struct trace_iterator *iter)
> +{
> + struct trace_entry *entry = iter->ent;
> + struct trace_seq *s = &iter->seq;
> + struct trace_ksym *field;
> + char str[KSYM_SYMBOL_LEN];
> + int ret;
> +
> + if (entry->type != TRACE_KSYM)
> + return TRACE_TYPE_UNHANDLED;

Looks good.

Acked-by:Steven Rostedt <srostedt@xxxxxxxxxx>

Thanks,

-- Steve

> +
> + trace_assign_type(field, entry);
> +
> + ret = trace_seq_printf(s, "%-15s %-5d %-3d %-20s ", field->p_name,
> + entry->pid, iter->cpu, field->ksym_name);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + switch (field->ksym_hbp->info.type) {
> + case HW_BREAKPOINT_WRITE:
> + ret = trace_seq_printf(s, " W ");
> + break;
> + case HW_BREAKPOINT_RW:
> + ret = trace_seq_printf(s, " RW ");
> + break;
> + default:
> + return TRACE_TYPE_PARTIAL_LINE;
> + }
> +
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + sprint_symbol(str, field->ip);
> + ret = trace_seq_printf(s, "%-20s\n", str);
> + if (!ret)
> + return TRACE_TYPE_PARTIAL_LINE;
> +
> + return TRACE_TYPE_HANDLED;
> +}
> +
--
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