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[67.165.245.5]) by smtp.googlemail.com with ESMTPSA id 8926c6da1cb9f-50a55df0940sm2268319173.106.2025.08.02.20.59.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 02 Aug 2025 20:59:21 -0700 (PDT) From: Jim Cromie To: linux-kernel@vger.kernel.org, jbaron@akamai.com, gregkh@linuxfoundation.org, ukaszb@chromium.org, louis.chauvet@bootlin.com Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, intel-gvt-dev@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, daniel.vetter@ffwll.ch, tvrtko.ursulin@linux.intel.com, jani.nikula@intel.com, ville.syrjala@linux.intel.com, seanpaul@chromium.org, robdclark@gmail.com, groeck@google.com, yanivt@google.com, bleung@google.com, quic_saipraka@quicinc.com, will@kernel.org, catalin.marinas@arm.com, quic_psodagud@quicinc.com, maz@kernel.org, arnd@arndb.de, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, mingo@redhat.com, jim.cromie@gmail.com Subject: [PATCH v4 32/58] dyndbg: refactor *dynamic_emit_prefix to split lookups Date: Sat, 2 Aug 2025 21:57:50 -0600 Message-ID: <20250803035816.603405-33-jim.cromie@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250803035816.603405-1-jim.cromie@gmail.com> References: <20250803035816.603405-1-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" Split dynamic_emit_prefix(): 1. keep dynamic_emit_prefix() static inline check ANY flags before calling 2 2. __dynamic_emit_prefix() prints [TID] or if +t flag check LOOKUP flags before calling 3 3. __dynamic_emit_lookup() prints 1+ of: module, function, src-file, line Notes: With 3 only called when needed, print the trailing whitespace unconditionally, and drop the pos_after_tid var. By doing TID in 2, 3's output is cacheable in principle. A prefix cache would allow de-duplicating the redundant data in the _ddebug tables, and replacing them with space-efficient storage which is not fast enough for every-time pr_debugs, but would work to fill the cache the 1st time its enabled and invoked. Signed-off-by: Jim Cromie --- lib/dynamic_debug.c | 40 +++++++++++++++++++++++++--------------- 1 file changed, 25 insertions(+), 15 deletions(-) diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c3e27637d9357..26261b5f99f05 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -824,19 +824,8 @@ static int remaining(int wrote) return 0; } =20 -static char *__dynamic_emit_prefix(const struct _ddebug *desc, char *buf) +static int __dynamic_emit_lookup(const struct _ddebug *desc, char *buf, in= t pos) { - int pos_after_tid; - int pos =3D 0; - - if (desc->flags & _DPRINTK_FLAGS_INCL_TID) { - if (in_interrupt()) - pos +=3D snprintf(buf + pos, remaining(pos), " "); - else - pos +=3D snprintf(buf + pos, remaining(pos), "[%d] ", - task_pid_vnr(current)); - } - pos_after_tid =3D pos; if (desc->flags & _DPRINTK_FLAGS_INCL_MODNAME) pos +=3D snprintf(buf + pos, remaining(pos), "%s:", desc->modname); @@ -849,8 +838,29 @@ static char *__dynamic_emit_prefix(const struct _ddebu= g *desc, char *buf) if (desc->flags & _DPRINTK_FLAGS_INCL_LINENO) pos +=3D snprintf(buf + pos, remaining(pos), "%d:", desc->lineno); - if (pos - pos_after_tid) - pos +=3D snprintf(buf + pos, remaining(pos), " "); + + /* we have a non-empty prefix, add trailing space */ + if (remaining(pos)) + buf[pos++] =3D ' '; + + return pos; +} + +static char *__dynamic_emit_prefix(struct _ddebug *desc, char *buf) +{ + int pos =3D 0; + + if (desc->flags & _DPRINTK_FLAGS_INCL_TID) { + if (in_interrupt()) + pos +=3D snprintf(buf + pos, remaining(pos), " "); + else + pos +=3D snprintf(buf + pos, remaining(pos), "[%d] ", + task_pid_vnr(current)); + } + + if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_LOOKUP)) + pos +=3D __dynamic_emit_lookup(desc, buf, pos); + if (pos >=3D PREFIX_SIZE) buf[PREFIX_SIZE - 1] =3D '\0'; =20 @@ -859,7 +869,7 @@ static char *__dynamic_emit_prefix(const struct _ddebug= *desc, char *buf) =20 static inline char *dynamic_emit_prefix(struct _ddebug *desc, char *buf) { - if (unlikely(desc->flags & _DPRINTK_FLAGS_INCL_ANY)) + if (desc->flags & _DPRINTK_FLAGS_INCL_ANY) return __dynamic_emit_prefix(desc, buf); return buf; } --=20 2.50.1