From: Steven Rostedt <rostedt@goodmis.org>
To: Anders Roxell <anders.roxell@linaro.org>
Cc: keescook@chromium.org, arnd@arndb.de, catalin.marinas@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org,
mingo@redhat.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3] tracing: add cond_resched to ftrace_replace_code()
Date: Tue, 4 Dec 2018 17:32:58 -0500 [thread overview]
Message-ID: <20181204173258.6de70c66@vmware.local.home> (raw)
In-Reply-To: <20181204194044.9506-1-anders.roxell@linaro.org>
On Tue, 4 Dec 2018 20:40:44 +0100
Anders Roxell <anders.roxell@linaro.org> wrote:
> When running in qemu on an kernel built with allmodconfig and debug
> options (in particular kcov and ubsan) enabled, ftrace_replace_code
> function call take minutes. The ftrace selftest calls
> ftrace_replace_code to look >40000 through
> ftrace_make_call/ftrace_make_nop, and these end up calling
> __aarch64_insn_write/aarch64_insn_patch_text_nosync.
>
> Microseconds add up because this is called in a loop for each dyn_ftrace
> record, and this triggers the softlockup watchdog unless we let it sleep
> occasionally.
>
> Rework so that we call cond_resched() if !irqs_disabled() && !preempt_count().
This isn't urgent is it? That is, it doesn't need a stable tag?
-- Steve
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next prev parent reply other threads:[~2018-12-04 22:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-04 19:40 [PATCH v3] tracing: add cond_resched to ftrace_replace_code() Anders Roxell
2018-12-04 22:32 ` Steven Rostedt [this message]
2018-12-05 10:50 ` Anders Roxell
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