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[106.167.137.155]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-22fc753fe13sm43549615ad.14.2025.05.11.02.27.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 11 May 2025 02:27:27 -0700 (PDT) Message-ID: <24beb2bb-b168-4849-804b-033c20ca352e@gmail.com> Date: Sun, 11 May 2025 18:27:26 +0900 Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: joelagnelf@nvidia.com Cc: paulmck@kernel.org, rcu@vger.kernel.org, Akira Yokosawa References: <20250421174717.3332525-1-joelagnelf@nvidia.com> Subject: Re: [PATCH v5] rcutorture: Perform more frequent testing of ->gpwrap Content-Language: en-US From: Akira Yokosawa In-Reply-To: <20250421174717.3332525-1-joelagnelf@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit [Trimmed most CCs] Hi Joel, I've got a warning from "make htmldocs" on top of rcu/next: [...]/kernel/rcu/tree.c:775: warning: cannot understand function prototype: 'unsigned long seq_gpwrap_lag = ULONG_MAX / 4; ' On Mon, 21 Apr 2025 13:47:15 -0400, Joel Fernandes wrote: [...] > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > index 659f83e71048..6ec30d07759d 100644 > --- a/kernel/rcu/tree.c > +++ b/kernel/rcu/tree.c [...] > @@ -757,6 +766,25 @@ void rcu_request_urgent_qs_task(struct task_struct *t) > smp_store_release(per_cpu_ptr(&rcu_data.rcu_urgent_qs, cpu), true); > } > > +/** > + * rcu_set_gpwrap_lag - Set RCU GP sequence overflow lag value. > + * @lag_gps: Set overflow lag to this many grace period worth of counters > + * which is used by rcutorture to quickly force a gpwrap situation. > + * @lag_gps = 0 means we reset it back to the boot-time value. > + */ This kernel-doc comment should be in front of its corresponding function prototype so that it is recognized as such. > +static unsigned long seq_gpwrap_lag = ULONG_MAX / 4; > + , so this static variable needs to go above the kernel-doc comment. > +void rcu_set_gpwrap_lag(unsigned long lag_gps) > +{ > + unsigned long lag_seq_count; > + > + lag_seq_count = (lag_gps == 0) > + ? ULONG_MAX / 4 > + : lag_gps << RCU_SEQ_CTR_SHIFT; > + WRITE_ONCE(seq_gpwrap_lag, lag_seq_count); > +} > +EXPORT_SYMBOL_GPL(rcu_set_gpwrap_lag); > + You can test it by saying: ./scripts/kernel-doc -none kernel/rcu/tree.c Thanks, Akira