Received: by 2002:a05:6358:1087:b0:cb:c9d3:cd90 with SMTP id j7csp4744783rwi; Sat, 22 Oct 2022 15:58:09 -0700 (PDT) X-Google-Smtp-Source: AMsMyM71oXBYP79Oqpudifg2snDg3+1FxvbFVtmSG7rfJagx7Xcwqo2ah2gqgjVg1xA55HmSxb9+ X-Received: by 2002:a17:907:1c8a:b0:782:1a0d:3373 with SMTP id nb10-20020a1709071c8a00b007821a0d3373mr20722148ejc.135.1666479489519; Sat, 22 Oct 2022 15:58:09 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1666479489; cv=none; d=google.com; s=arc-20160816; b=rIePC9bR3F6bSBxwValD9vW4QPJzyh/Ff9QCQurtpWQaXflfRNtMmFau580XTmjxtF voyp2Vvelj0ki9sLO8GFnhA3ovHqONONUOPyOdWVdgOXxNO0pVEcQTicJmt3Wqet/1NM CUwkWp9c/aoQrfzbBLR7gmXnmMI9vUg7pyGXNMScR3o4BL9zo5HXNY8Kkb9rYATAdp+Y +VYCq6q/Zdbh+ekPz08rBImISy6xnpcv5jc7J6nAzZ3PxFur6vjh7iqSJSbQ11+Nrc/I 4s8ym3S8BCdgXlUqgVbWyAEXVaQrVAIESbHiOXv4JKnJJ1KnXfMHAcsfJ9GJEHxVsXne MMLw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=ORhdzvQEaSdepN8FuCdBMVAeS8RbuY3+hyzMb2MUCmU=; b=KDYlaoibmzUPY46Q+Un97i9Il2KsRIc4kQuwcDqOhh25DVGY3aP+tE+dM/1gjSDczo hys10vcOr1U3FfkCesDoLfEQRpu1v670W9RRAVFD4jiPxjkmMxVj9KzqKf5DWeJySs44 5y28QCThQ/jLsOBuHOZPqN/bkm8X30qjW+XXyD9iEXThGWCfysqDPudoTbona6HRzhK1 cFzuiyL6ZafBYBGH2W/5BlGheHssLeaK4APuvenOQhCstNFpxoVVSZ9oarav5Od4zgV8 S+svh0vn+5UNZclwgV4Yk6nb1MXSReTTJylMUT2IHVOHzlFARnhbT9WAfFxQ+08Ql4wx eoyA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b="cmegG/cQ"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id sa19-20020a1709076d1300b0078dcdbe650fsi21851968ejc.443.2022.10.22.15.57.41; Sat, 22 Oct 2022 15:58:09 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20210112 header.b="cmegG/cQ"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229817AbiJVWyH (ORCPT + 99 others); Sat, 22 Oct 2022 18:54:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229519AbiJVWyC (ORCPT ); Sat, 22 Oct 2022 18:54:02 -0400 Received: from mail-io1-xd31.google.com (mail-io1-xd31.google.com [IPv6:2607:f8b0:4864:20::d31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A99E80F77 for ; Sat, 22 Oct 2022 15:54:01 -0700 (PDT) Received: by mail-io1-xd31.google.com with SMTP id b79so5099999iof.5 for ; Sat, 22 Oct 2022 15:54:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ORhdzvQEaSdepN8FuCdBMVAeS8RbuY3+hyzMb2MUCmU=; b=cmegG/cQDs9JlhTYb5B/1Yps85vDQaZe03tGZYWlnQUdwwlRGUTFrOs5tyvcOTGvEM c6V+nXWdwsbn4a5bPYs99R6i792gXqvKN7u1Ehni4ivH4PEkkUmA8XKcP+tzRru7LdLU sRkoyXnem6Msk2BBa9c56OlWsevI160fSBVhWuQEAyLQixWEkdz/rEo7PXJzzF9v2yOy z1sd9A+cyB7ikWu2SB1rJC+bcqGFwBndlh4SKlNui9krsVp7KwZ7sJeD823B94NXEkeg TCXvNxfAUP/iU6qv5oxr0n9tauN7rU4mYby6QhNT6EIf9zc4+7BpgODEBfuqeO1dP45U zUlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ORhdzvQEaSdepN8FuCdBMVAeS8RbuY3+hyzMb2MUCmU=; b=ymBkUSpSKrd+VN0eMmLSBDaqe2bwtlEE+daHDv1/nRwuslimNUB7R7/T7AT36mt7Op aEN21Ee9+x8z8On7UVQPCIIX9V9NuG31ulSbPXFRFxCO3y/ZudK7GG0C7NQETvPh3ydz WQ5cyw20N8TjKgXoJS450NzHZ8i4IRaBzpsDglqmcnArgch0ZKadl6DncvUFrGEDL4CI gH8n4WDTCs/tqhAg0mWDIZcZiBfJ3++Kj8dVkBgm5rNEO5JIqAV9eiwjj2CdUz6lvpx4 LL+JCWEuVZGTLfrgGb1H5wQEK4zWTlBQz+K7ge0o6ThgX0TPWh+BQ+y4MncnnsZ+8YT+ w2sg== X-Gm-Message-State: ACrzQf1NjMFIK5NKR91CftdoZuzhF8Qxuj0x2Bds1Xi/iMbBYU54pvXV j6kcSVm9PZjrCJ+2thWYtR4swgzTe8c= X-Received: by 2002:a05:6638:16ce:b0:363:b8b5:8d6b with SMTP id g14-20020a05663816ce00b00363b8b58d6bmr19093815jat.194.1666479240444; Sat, 22 Oct 2022 15:54:00 -0700 (PDT) Received: from frodo.. (c-73-78-62-130.hsd1.co.comcast.net. [73.78.62.130]) by smtp.googlemail.com with ESMTPSA id y19-20020a056e02119300b002ffcf2e2e05sm534189ili.58.2022.10.22.15.53.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Oct 2022 15:53:59 -0700 (PDT) From: Jim Cromie To: linux-kernel@vger.kernel.org, jbaron@akamai.com, gregkh@linuxfoundation.org Cc: Jim Cromie Subject: [PATCH 2/2] vmlinux.lds.h: add a KEEP .gnu.linkonce.##_name into BOUNDED_SECTION Date: Sat, 22 Oct 2022 16:53:50 -0600 Message-Id: <20221022225351.1406492-3-jim.cromie@gmail.com> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221022225351.1406492-1-jim.cromie@gmail.com> References: <20221022225351.1406492-1-jim.cromie@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Extend recently added BOUNDED_SECTION(_name) macro by adding a KEEP(*(.gnu.linkonce.##_name)) before the KEEP(*(_name)). This does nothing by itself, vmlinux is the same before and after this patch. But if a developer adds a .gnu.linkonce.foo record, that record is placed in the front of the section, where it can be used as a header for the table. The intent is to create an up-link to another organizing struct, from where related tables can be referenced. And since every item in a table has a known offset from its header, that same offset can be used to fetch records from the related tables. By itself, this doesnt gain much, unless maybe the pattern of access is to scan 1 or 2 fields in each fat record, but with 2 16 bit .map* fields added, we could de-duplicate 2 related tables. The use case here is struct _ddebug, which has 3 pointers (function, file, module) with substantial repetition; respectively 53%, 90%, and the module column is fully recoverable after dynamic_debug_init() splits the table into a linked list of "module" chunks. On a DYNAMIC_DEBUG=y kernel with 5k pr_debugs, the memory savings should be ~100 KiB. Signed-off-by: Jim Cromie --- ? does this need a new name ? HEADERED_SECTION ? --- include/asm-generic/vmlinux.lds.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 9f6352171f88..b3ca56ac163f 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -195,11 +195,13 @@ #define BOUNDED_SECTION_PRE_LABEL(_sec_, _label_, _s_, _e_) \ _s_##_label_ = .; \ + KEEP(*(.gnu.linkonce.##_sec_)) \ KEEP(*(_sec_)) \ _e_##_label_ = .; #define BOUNDED_SECTION_POST_LABEL(_sec_, _label_, _s_, _e_) \ _label_##_s_ = .; \ + KEEP(*(.gnu.linkonce.##_sec_)) \ KEEP(*(_sec_)) \ _label_##_e_ = .; -- 2.37.3