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[98.38.17.99]) by smtp.googlemail.com with ESMTPSA id 46e09a7af769-7dbb7c3a0c8sm1806671a34.12.2026.04.03.07.24.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2026 07:24:10 -0700 (PDT) From: Jim Cromie To: peterz@infradead.org, gregkh@linuxfoundation.org Cc: jpoimboe@kernel.org, jbaron@akamai.com, aliceryhl@google.com, rostedt@goodmis.org, ardb@kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Jim Cromie Subject: [PATCH 3/5] dyndbg: use static-key queueing API in dynamic-debug Date: Fri, 3 Apr 2026 08:23:59 -0600 Message-ID: <20260403142401.1387033-4-jim.cromie@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260403142401.1387033-1-jim.cromie@gmail.com> References: <20260403142401.1387033-1-jim.cromie@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Use the new static-key queueing API in dynamic-debug to reduce IPIs. this replaces the 2 calls to static_branch_{enable.disable}() in ddebug_change() with their _queued() counterparts, and adds a call to static_branch_apply_queued() at the bottom. This gives a theoretical reduction of IPIs up to 256x, and a practical reduction by 120-180x. Signed-off-by: Jim Cromie --- lib/dynamic_debug.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index b5060749464e..9bee7dde5148 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -250,9 +250,9 @@ static int ddebug_change(const struct ddebug_query *que= ry, #ifdef CONFIG_JUMP_LABEL if (dp->flags & _DPRINTK_FLAGS_PRINT) { if (!(newflags & _DPRINTK_FLAGS_PRINT)) - static_branch_disable(&dp->key.dd_key_true); + static_branch_disable_queued(&dp->key.dd_key_true); } else if (newflags & _DPRINTK_FLAGS_PRINT) { - static_branch_enable(&dp->key.dd_key_true); + static_branch_enable_queued(&dp->key.dd_key_true); } #endif v4pr_info("changed %s:%d [%s]%s %s =3D> %s\n", @@ -263,6 +263,7 @@ static int ddebug_change(const struct ddebug_query *que= ry, dp->flags =3D newflags; } } + static_branch_apply_queued(); mutex_unlock(&ddebug_lock); v2pr_info("applied %d queued updates to sites in total\n", nfound); =20 --=20 2.53.0