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Miller" , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH v4 02/21] x86/hw_breakpoint: Add arch_reinstall_hw_breakpoint Message-Id: <20250914225306.2185b79065e32f60a40ef54c@kernel.org> In-Reply-To: <20250912101145.465708-3-wangjinchao600@gmail.com> References: <20250912101145.465708-1-wangjinchao600@gmail.com> <20250912101145.465708-3-wangjinchao600@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 47C15120003 X-Stat-Signature: ebf5bddemarkk8ycug9foh59atx6t7rb X-Rspam-User: X-HE-Tag: 1757858001-369496 X-HE-Meta: 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 oDulvVsc HNrYeoEXyYcM1ggLTF46Y2eux9C/8Sopq+2rScC2K5s72a9VVwtVAcYhDBDa137E9hPeq+5KHPg5aR6zTqaYNF5tXYijc1nQcD5XCCynMRdIX20VS9YSxD5yGXxn4Z8rx5eEWGpOwbcdzc25aKCBjkk/9/rjpkWBMwLXQgRjgFj5xU/eyDBSKFISWjn8hLEO1hWQ4V20g25iksFRjFyX2TGWnbaWFeZF6KScBT0GSGB8Jvu9DeUE5xQlRuPmWtln/8Rjk33ekkm8sF82HOJOxi46ZdT5Ig7iJQbG7aaKBPN2wI40zoDlscZ7gHn1MJcRY6Elmno5YBE1tUm0Pmywp7o32HwBy3NNpwuyR3W7RW28bEAVU6CZKr+Xnb7ANRwv8NeJBoj9RG35Grdj8k7Du+JfYSrPkQ+3vItQO X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 12 Sep 2025 18:11:12 +0800 Jinchao Wang wrote: > The new arch_reinstall_hw_breakpoint() function can be used in an > atomic context, unlike the more expensive free and re-allocation path. > This allows callers to efficiently re-establish an existing breakpoint. > Looks good to me. Reviewed-by: Masami Hiramatsu (Google) Thanks! > Signed-off-by: Jinchao Wang > --- > arch/x86/include/asm/hw_breakpoint.h | 2 ++ > arch/x86/kernel/hw_breakpoint.c | 9 +++++++++ > 2 files changed, 11 insertions(+) > > diff --git a/arch/x86/include/asm/hw_breakpoint.h b/arch/x86/include/asm/hw_breakpoint.h > index aa6adac6c3a2..c22cc4e87fc5 100644 > --- a/arch/x86/include/asm/hw_breakpoint.h > +++ b/arch/x86/include/asm/hw_breakpoint.h > @@ -21,6 +21,7 @@ struct arch_hw_breakpoint { > > enum bp_slot_action { > BP_SLOT_ACTION_INSTALL, > + BP_SLOT_ACTION_REINSTALL, > BP_SLOT_ACTION_UNINSTALL, > }; > > @@ -65,6 +66,7 @@ extern int hw_breakpoint_exceptions_notify(struct notifier_block *unused, > > > int arch_install_hw_breakpoint(struct perf_event *bp); > +int arch_reinstall_hw_breakpoint(struct perf_event *bp); > void arch_uninstall_hw_breakpoint(struct perf_event *bp); > void hw_breakpoint_pmu_read(struct perf_event *bp); > void hw_breakpoint_pmu_unthrottle(struct perf_event *bp); > diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c > index 3658ace4bd8d..29c9369264d4 100644 > --- a/arch/x86/kernel/hw_breakpoint.c > +++ b/arch/x86/kernel/hw_breakpoint.c > @@ -99,6 +99,10 @@ static int manage_bp_slot(struct perf_event *bp, enum bp_slot_action action) > old_bp = NULL; > new_bp = bp; > break; > + case BP_SLOT_ACTION_REINSTALL: > + old_bp = bp; > + new_bp = bp; > + break; > case BP_SLOT_ACTION_UNINSTALL: > old_bp = bp; > new_bp = NULL; > @@ -187,6 +191,11 @@ int arch_install_hw_breakpoint(struct perf_event *bp) > return arch_manage_bp(bp, BP_SLOT_ACTION_INSTALL); > } > > +int arch_reinstall_hw_breakpoint(struct perf_event *bp) > +{ > + return arch_manage_bp(bp, BP_SLOT_ACTION_REINSTALL); > +} > + > void arch_uninstall_hw_breakpoint(struct perf_event *bp) > { > arch_manage_bp(bp, BP_SLOT_ACTION_UNINSTALL); > -- > 2.43.0 > > -- Masami Hiramatsu (Google)