From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa2-f12.google.com (mail-oa2-f12.google.com [74.125.231.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7156D3B05AF for ; Tue, 22 Sep 2026 20:08:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790107727; cv=none; b=I2lFtyPWQwR6GisHW58ex+dVayY0kPf/7DONrP6HdW7AsqG0YCy0+zJTap7KUl9PRNbGAUQWfWDrBEHo5yi5bd5qDqRf2SSnnAXwQ6l/8BL/Uvz/3mmvXvE16iCKyl/BcFa89K0B/3kgfy4NBofs3ARwtYOAfCXe0MrMVowWGP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790107727; c=relaxed/simple; bh=q0sZDppUsa+eu5sPpZoAEi+M6OKVy6NJVptfUVXehJQ=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=fiQ1lLSV4ldUSOjTPVIGTfROPAbA4Ir3OBgG2gwp4nXkItRPdr9/4nEq9VKM2+156/Ey8Gz86Yzp+H1WdiJUxwXJ6oKQ68a/YUo6cdbujsoUxKTOBXytvggFtEJLzkci4V+dJ6QDlEXOBUBKat7wvf5M2L9HCXCUNXs9HbVv9og= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=h1+oAekl; arc=none smtp.client-ip=74.125.231.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="h1+oAekl" Received: by mail-oa2-f12.google.com with SMTP id 586e51a60fabf-466cc9b2f02so89935fac.1 for ; Tue, 22 Sep 2026 13:08:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790107711; x=1790712511; darn=vger.kernel.org; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=AlFlDOH8oZxKnMeTYk9lUtSf3sYQz7J3e363i7elvXc=; b=h1+oAekldty/KlscOKiGPYVEtvgOO2vLr2xMaL1f78rh2FMC/qnCkoKhbEm2U/fsrv 1h7wA/Mpc2IJobVP8meGgjHsOatUjfbWcHaWQOMkbypk0+/3UHKafiXnok3Th06GOmw6 kUMYL3njRRlIbisYK7A7jZCm3vUTiYPdysm2ZMzvM5XxOm4xYS8lJBwSrsu2i5QgTxN4 jObObBzwlpvEWRIgnXb0X+NvxD1MLge0vgs5o7rNNMMYtFkmgDKlYXDU7EqHEN7SpWpm 7fYq+lZqQ+ZJdG/fM0XQ6Trhrqx2+2qipAN7fyk+XYOVcynfJwfQ/7ifnPCjLpZmhWZI r0Ag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790107711; x=1790712511; h=cc:to:in-reply-to:references:message-id:content-transfer-encoding :content-type:mime-version:subject:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=AlFlDOH8oZxKnMeTYk9lUtSf3sYQz7J3e363i7elvXc=; b=yseMbVXvmNoNfupYRIPVSryb/qKlejiZnjiDKZDJmVpkiZd6DuEE1+lrdfIkmoxpBF 77oGN/8fr0iWnPH7jE8qUuuZyq46oV5V/oZ3TtO4zwv/Y2RGA+IOQ+TN63F6pPV2wdHF UVY5cjKVXiV1GUSU9QlfUQ6ZpSIwRYoxE24sg6cvKWqtgqMcQ2K0HpS5+ioTC4sx1Dxl n78wsJstlf+rZPB4gyJ9yANPNro/6viGV1dhUHZZivz3XQCeURfrliNlxZ2s87YKUFLb H5tg9qzcROVThMxLsesk2j1cMdKgsL+LsxJ8CXUXztNITxx2LxJOakyVZGUNTAOfqK3n BSuA== X-Forwarded-Encrypted: i=1; AKwUvBzBKhgAe/Cegsl2Yu59iuiaHwFVLCEFi7wV8ZzNEpk39pGpckGFQVZ1CpdxolthnA/h5LGVQ++lEjBwC48=@vger.kernel.org X-Gm-Message-State: AFuF++m7d+3OqojYYwxIEAWdHryB7u7vKtIuFtdq1abkxBQmKxQDcLIV zlxuGE0ddO0Zr7tm0OXBQzFUCvFupIFMf7DGFK5AJ80a2icepqwmDhJS X-Gm-Gg: AYBFou2+M0sUqnOe3urlh2NPGm9bCmVOpFohoicQXtdkbo+90G6yoCdVSg6TiSsshbC NedL+uAQocIO+3ASKDF+/oSzohAK7RrIPhYR78YyBr5gNagZzR1rZO2VHyTWSbJliznASYJoMZj MyumdePjP9A2K+XSUDLB3Vtf01bB8fnYziU7OamWezoj7dwb06uFxAzG9MJ2bRCswYw5FSKwql0 Cijkedxk5J3CaU2keECZFiblwEW3ncZjEad6SFsTkFnpqUC+nejBWOTK+RYKoilDKn/noIuC1My n0om7yV+QEF9mWXgvNsrB0YEB3pCS3htFtOLpP2aPhgzVFAZXCK+xTYgrjU535oYPASxyEWF7vO FWNdpwL6R95D8c6EYLdpKrpcfBWiISbhlbICpAZB1cp9mA5GaO++rzLcxqpYYbFMg80T5M8ST+w yvjUd9zMqAtvi12nGM4v7MJbRPHzMnL2r5xdAlfMN0QHl84xz896lQymacpDUt5Ul8HP3ZveaWs KNFTmI9AdzaWVcKZEw/mS825wiuFVBwl5b1zc9WX799tpqr48MIi+ln3QEcQYHg6OpXHhj4cl+j uNn1n7wgZG/ydb9Mz8OSAeVCdFtKUSV1M4VQ7FLg X-Received: by 2002:a05:6870:e996:b0:48f:82a7:84cc with SMTP id 586e51a60fabf-4908e34ec00mr569116fac.0.1790107711491; Tue, 22 Sep 2026 13:08:31 -0700 (PDT) Received: from [100.82.231.29] (c-98-38-17-99.hsd1.co.comcast.net. [98.38.17.99]) by smtp.googlemail.com with ESMTPSA id 586e51a60fabf-4908eb9237asm564087fac.12.2026.09.22.13.08.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2026 13:08:31 -0700 (PDT) From: Jim Cromie Date: Tue, 22 Sep 2026 14:08:21 -0600 Subject: [PATCH v4 4/4] kallsyms: Unroll 24-bit sequence reconstruction in get_symbol_seq() Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260922-ksyms-tune-v4-4-92acea84b911@gmail.com> References: <20260922-ksyms-tune-v4-0-92acea84b911@gmail.com> In-Reply-To: <20260922-ksyms-tune-v4-0-92acea84b911@gmail.com> To: Andrew Morton Cc: Lorenzo Stoakes , Kees Cook , David Laight , Masahiro Yamada , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, bpf@vger.kernel.org, Jim Cromie X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1790107704; l=1647; i=jim.cromie@gmail.com; s=20260203; h=from:subject:message-id; bh=q0sZDppUsa+eu5sPpZoAEi+M6OKVy6NJVptfUVXehJQ=; b=YtdomdHVifgDSmUNlCebB5wNAipNPmPSACPDou6l7lL+wvQSUi9uR5FwEr5jNvxcdDOPZLnBM 6f2Qs6omN03AmSblhpXa5N5LBIdHGXVNnX0ZTVbc9Yh66o/qdxqaklq X-Developer-Key: i=jim.cromie@gmail.com; a=ed25519; pk=C6E5ODlPQo7ZBynATXH9wg7K6HxP0pIXyf4s38Qw0XE= kallsyms_seqs_of_names[] stores 3-byte big-endian sequence indices that map alphabetical symbol positions to address-ordered symbol records. Currently, get_symbol_seq() reconstructs each 24-bit integer using a 3-iteration for-loop that shifts and bitwise-ORs each byte sequentially. During binary search in kallsyms_lookup_names() and duplicate boundary scans, this loop introduces branch and loop overhead on the hot lookup path. Mark get_symbol_seq() as static inline and unroll the 3-byte extraction into direct byte shifts: (p[0] << 16) | (p[1] << 8) | p[2]. This eliminates loop induction variable maintenance and allows the compiler to generate direct loads and constant shifts. Signed-off-by: Jim Cromie --- Changes in v3: - Added as a standalone micro-optimization patch (addresses David Laight review). --- kernel/kallsyms.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index bb34b4c0f690..35484361201f 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -280,14 +280,11 @@ unsigned long kallsyms_sym_address(int idx) return (unsigned long)offset_to_ptr(kallsyms_offsets + idx); } -static unsigned int get_symbol_seq(int index) +static inline unsigned int get_symbol_seq(int index) { - unsigned int i, seq = 0; + const u8 *p = &kallsyms_seqs_of_names[3 * index]; - for (i = 0; i < 3; i++) - seq = (seq << 8) | kallsyms_seqs_of_names[3 * index + i]; - - return seq; + return (p[0] << 16) | (p[1] << 8) | p[2]; } static int kallsyms_lookup_names(const char *name, -- 2.55.0