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Tue, 18 Nov 2025 11:06:51 -0800 (PST) Received: from localhost ([116.86.198.140]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7b927150b13sm17152641b3a.46.2025.11.18.11.06.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Nov 2025 11:06:51 -0800 (PST) Date: Wed, 19 Nov 2025 03:06:50 +0800 From: Chris Down To: Petr Mladek Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Sergey Senozhatsky , Steven Rostedt , John Ogness , Geert Uytterhoeven , Tony Lindgren , kernel-team@fb.com Subject: [PATCH v7 01/13] printk: Avoid delaying messages that aren't solicited by any console Message-ID: <8c69a5fccc15a512e5ba6385f3c933e3d2f8a96b.1763492585.git.chris@chrisdown.name> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.2.15 (2b349c5e) (2025-10-02) Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" printk_delay() may introduce delays even when no console wants to emit the message, which is unnecessary and may hold back messages we actually care about. Add a check in printk_delay() to determine if any console will print the message to avoid introducing unnecessary delays. This change aligns with the existing behaviour of boot-delayed printk messages, which already have a similar check. Reviewed-by: Petr Mladek Signed-off-by: Chris Down --- kernel/printk/printk.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 5aee9ffb16b9..ff8b6dbb29a7 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1307,14 +1307,12 @@ static int __init boot_delay_setup(char *str) } early_param("boot_delay", boot_delay_setup); =20 -static void boot_delay_msec(int level) +static void boot_delay_msec(void) { unsigned long long k; unsigned long timeout; - bool suppress =3D !is_printk_force_console() && - suppress_message_printing(level); =20 - if ((boot_delay =3D=3D 0 || system_state >=3D SYSTEM_RUNNING) || suppress) + if (boot_delay =3D=3D 0 || system_state >=3D SYSTEM_RUNNING) return; =20 k =3D (unsigned long long)loops_per_msec * boot_delay; @@ -1334,7 +1332,7 @@ static void boot_delay_msec(int level) } } #else -static inline void boot_delay_msec(int level) +static inline void boot_delay_msec(void) { } #endif @@ -2116,7 +2114,11 @@ int printk_delay_msec __read_mostly; =20 static inline void printk_delay(int level) { - boot_delay_msec(level); + /* If the message is forced (e.g. panic), we must delay */ + if (!is_printk_force_console() && suppress_message_printing(level)) + return; + + boot_delay_msec(); =20 if (unlikely(printk_delay_msec)) { int m =3D printk_delay_msec; --=20 2.51.2