From patchwork Tue Jan 10 22:20:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ian Rogers X-Patchwork-Id: 13095716 X-Patchwork-Delegate: bpf@iogearbox.net 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 D3BD2C54EBC for ; Tue, 10 Jan 2023 22:21:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235238AbjAJWVv (ORCPT ); Tue, 10 Jan 2023 17:21:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235251AbjAJWVV (ORCPT ); Tue, 10 Jan 2023 17:21:21 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0777910B44 for ; Tue, 10 Jan 2023 14:20:57 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-434eb7c6fa5so143081087b3.14 for ; Tue, 10 Jan 2023 14:20:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=b4cDFSVYG43croOnEV27nNQKcdSJ0iRzIK+gxT25DWQ=; b=oWwqPFHv+dZCSeNo+f2delVO4bkS5CysJ1Fb9cTlI9zPxRA7uKaiJ7fzrQAE/gTePN yQdJfBq26Z53aSri1L4flICMFvFNUevMxBBdhNvHv8Ijb0Oku7b8R3i1GIZwAS7jcJ22 jMmWxbFtkBzDL/R9uaLOc+rwZEKLhEkSnycWiK+bJoz5ZUvP8k/r3gzwpyc58iJZ/qIR uFv/RK4kFlujjtJHI9F8csecrHrl/8oIz/UTVfp75WDyghQbB2noKVROCgEIL9/hytzp 05/J55rtJDAGcO6Q4BwMKuBUc0CZ06wbMj2tK5aFbb8NTedwer0JBGvwhthbuu/kH2CO qRSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=b4cDFSVYG43croOnEV27nNQKcdSJ0iRzIK+gxT25DWQ=; b=BbPV/gU/C9tzONg1XTk+nGq9m8fCHCxGXjXN48MxiyF1sVUhhQ7NjpGr5vsqGxIF9k iT1W1weDOAWqOuAconHF/3MWktt7AHJlTp1w/uW4eDomiAmqpeJtC8x8z3Muig52X0Gk pQqbzjyZyuR+rErwmxtjU/xKSfYRnl5yZ+91j7ndNhlEjN5eGNIO6MUOUsYvF/PeMnxX isAAooZ/NlIZBllBy+KKOMSKjCPfmG+6hd3jXfDDL6grhs5KYitqvu0tNCr293Ozf1Ji TCbry73nvYHi4Jvbo1+3qiKXS8HaC25O2Mexnne3H11JTPBGUS26z7C0VrCNsS1BiHaQ Rclg== X-Gm-Message-State: AFqh2kree/bZACQdqrJaCSkRaNEsffh3suFhKAp1m6JdQywP4R+3xWnL BMCChGMMDpaarbj/Q2P3W4qtzpfi+RxY X-Google-Smtp-Source: AMrXdXvI95ryIYv3mYiLaEW52Mjy6G2g6DQ8MwrTjJmJYfZaK+uEyVB7Y9YgTbG/z/1GFMv0iQnxIls+z2Xi X-Received: from irogers.svl.corp.google.com ([2620:15c:2d4:203:cebf:c37e:8184:56]) (user=irogers job=sendgmr) by 2002:a25:9a02:0:b0:7ba:f028:b325 with SMTP id x2-20020a259a02000000b007baf028b325mr1547877ybn.452.1673389256480; Tue, 10 Jan 2023 14:20:56 -0800 (PST) Date: Tue, 10 Jan 2023 14:20:00 -0800 In-Reply-To: <20230110222003.1591436-1-irogers@google.com> Message-Id: <20230110222003.1591436-5-irogers@google.com> Mime-Version: 1.0 References: <20230110222003.1591436-1-irogers@google.com> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog Subject: [PATCH v1 4/7] tools lib api: Minor strbuf_read improvements From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Nathan Chancellor , Nick Desaulniers , Tom Rix , Nicolas Schier , Masahiro Yamada , Athira Rajeev , Christy Lee , Andrii Nakryiko , Ravi Bangoria , Leo Yan , Yang Jihong , Qi Liu , James Clark , Adrian Hunter , "Masami Hiramatsu (Google)" , Kan Liang , Sean Christopherson , Zhengjun Xing , Rob Herring , Xin Gao , Zechuan Chen , Jason Wang , Christophe JAILLET , Stephane Eranian , German Gomez , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, bpf@vger.kernel.org, llvm@lists.linux.dev Cc: Ian Rogers Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org If a read is smaller than the remaining space, don't grow the buffer as it is likely we've reached the end of the file. Make the grow amounts a single page rather than just over 2 once the null terminator is included. Signed-off-by: Ian Rogers --- tools/lib/api/strbuf.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/tools/lib/api/strbuf.c b/tools/lib/api/strbuf.c index 4639b2d02e62..eafa2c01f46a 100644 --- a/tools/lib/api/strbuf.c +++ b/tools/lib/api/strbuf.c @@ -143,25 +143,28 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, ssize_t hint) size_t oldalloc = sb->alloc; int ret; - ret = strbuf_grow(sb, hint ? hint : 8192); + ret = strbuf_grow(sb, hint ? hint : 4095); if (ret) return ret; for (;;) { - ssize_t cnt; + ssize_t read_size; + size_t sb_remaining = sb->alloc - sb->len - 1; - cnt = read(fd, sb->buf + sb->len, sb->alloc - sb->len - 1); - if (cnt < 0) { + read_size = read(fd, sb->buf + sb->len, sb_remaining); + if (read_size < 0) { if (oldalloc == 0) strbuf_release(sb); else strbuf_setlen(sb, oldlen); - return cnt; + return read_size; } - if (!cnt) + if (read_size == 0) break; - sb->len += cnt; - ret = strbuf_grow(sb, 8192); + sb->len += read_size; + if ((size_t)read_size < sb_remaining) + continue; + ret = strbuf_grow(sb, 4095); if (ret) return ret; }