From nobody Mon Feb 9 14:32:39 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5774C433FE for ; Wed, 2 Nov 2022 08:51:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230383AbiKBIvA (ORCPT ); Wed, 2 Nov 2022 04:51:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53668 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230424AbiKBIud (ORCPT ); Wed, 2 Nov 2022 04:50:33 -0400 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5150C27CFD; Wed, 2 Nov 2022 01:50:31 -0700 (PDT) Received: from dggpemm500020.china.huawei.com (unknown [172.30.72.53]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4N2LFG1g3fz15MF2; Wed, 2 Nov 2022 16:50:26 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500020.china.huawei.com (7.185.36.49) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 2 Nov 2022 16:50:28 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Wed, 2 Nov 2022 16:50:28 +0800 From: Zhen Lei To: Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , , , Masahiro Yamada , Alexei Starovoitov , Jiri Olsa , Kees Cook , Andrew Morton , "Luis Chamberlain" , , "Steven Rostedt" , Ingo Molnar CC: Zhen Lei , David Laight Subject: [PATCH v8 4/9] kallsyms: Reduce the memory occupied by kallsyms_seqs_of_names[] Date: Wed, 2 Nov 2022 16:49:16 +0800 Message-ID: <20221102084921.1615-5-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20221102084921.1615-1-thunder.leizhen@huawei.com> References: <20221102084921.1615-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" kallsyms_seqs_of_names[] records the symbol index sorted by address, the maximum value in kallsyms_seqs_of_names[] is the number of symbols. And 2^24 =3D 16777216, which means that three bytes are enough to store the index. This can help us save (1 * kallsyms_num_syms) bytes of memory. Signed-off-by: Zhen Lei --- kernel/kallsyms.c | 18 ++++++++++++++---- kernel/kallsyms_internal.h | 2 +- scripts/kallsyms.c | 5 ++++- 3 files changed, 19 insertions(+), 6 deletions(-) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index ba351dfa109b6ac..48f36fd7e10b95e 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -201,6 +201,16 @@ static int compare_symbol_name(const char *name, char = *namebuf) return ret; } =20 +static unsigned int get_symbol_seq(int index) +{ + unsigned int i, seq =3D 0; + + for (i =3D 0; i < 3; i++) + seq =3D (seq << 8) | kallsyms_seqs_of_names[3 * index + i]; + + return seq; +} + static int kallsyms_lookup_names(const char *name, unsigned int *start, unsigned int *end) @@ -215,7 +225,7 @@ static int kallsyms_lookup_names(const char *name, =20 while (low <=3D high) { mid =3D low + (high - low) / 2; - seq =3D kallsyms_seqs_of_names[mid]; + seq =3D get_symbol_seq(mid); off =3D get_symbol_offset(seq); kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); ret =3D compare_symbol_name(name, namebuf); @@ -232,7 +242,7 @@ static int kallsyms_lookup_names(const char *name, =20 low =3D mid; while (low) { - seq =3D kallsyms_seqs_of_names[low - 1]; + seq =3D get_symbol_seq(low - 1); off =3D get_symbol_offset(seq); kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); if (compare_symbol_name(name, namebuf)) @@ -244,7 +254,7 @@ static int kallsyms_lookup_names(const char *name, if (end) { high =3D mid; while (high < kallsyms_num_syms - 1) { - seq =3D kallsyms_seqs_of_names[high + 1]; + seq =3D get_symbol_seq(high + 1); off =3D get_symbol_offset(seq); kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); if (compare_symbol_name(name, namebuf)) @@ -269,7 +279,7 @@ unsigned long kallsyms_lookup_name(const char *name) =20 ret =3D kallsyms_lookup_names(name, &i, NULL); if (!ret) - return kallsyms_sym_address(kallsyms_seqs_of_names[i]); + return kallsyms_sym_address(get_symbol_seq(i)); =20 return module_kallsyms_lookup_name(name); } diff --git a/kernel/kallsyms_internal.h b/kernel/kallsyms_internal.h index a04b7a5cb1e3eaf..27fabdcc40f5793 100644 --- a/kernel/kallsyms_internal.h +++ b/kernel/kallsyms_internal.h @@ -26,6 +26,6 @@ extern const char kallsyms_token_table[] __weak; extern const u16 kallsyms_token_index[] __weak; =20 extern const unsigned int kallsyms_markers[] __weak; -extern const unsigned int kallsyms_seqs_of_names[] __weak; +extern const u8 kallsyms_seqs_of_names[] __weak; =20 #endif // LINUX_KALLSYMS_INTERNAL_H_ diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 07ecf7e5c49f616..04e04fbd9625caf 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -600,7 +600,10 @@ static void write_src(void) sort_symbols_by_name(); output_label("kallsyms_seqs_of_names"); for (i =3D 0; i < table_cnt; i++) - printf("\t.long\t%u\n", table[i]->seq); + printf("\t.byte 0x%02x, 0x%02x, 0x%02x\n", + (unsigned char)(table[i]->seq >> 16), + (unsigned char)(table[i]->seq >> 8), + (unsigned char)(table[i]->seq >> 0)); printf("\n"); =20 output_label("kallsyms_token_table"); --=20 2.25.1