forked from pool/elfutils
51 lines
2.0 KiB
Diff
51 lines
2.0 KiB
Diff
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From 31d6b1fe74ab89138b4d256742997b730dc5cba8 Mon Sep 17 00:00:00 2001
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From: "Frank Ch. Eigler" <fche@redhat.com>
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Date: Mon, 15 Aug 2022 06:20:10 -0400
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Subject: [PATCH] PR29474: debuginfod
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Previous code sometimes confused debuginfod with concurrent queries
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targeting the same RPM. One thread fetching & prefetching, the other
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thread misinterpreted the sudden presence of its target file in the
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fdcache as a mere unnecessary prefetch duplicate. But if it was the
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other thread's target file, previous code would -skip- it completely,
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resulting in a 404 error. New code allows the other thread to also
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decompress the target file and return it, and still continue to its
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own prefetching process for other files.
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There's a performance trade-off here. Another option would be for the
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other thread to check the fdcache regularly and abort its own
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prefetch/fetch/prefetch loop early in case of a sudden target file
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hit. That'd save CPU probably but it'd stop prefetching of later
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segments of the input archive, which could save future time.
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Automated testing is too time/load sensitive to attempt. Confirmed
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working with Martin's stress tester.
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Reported-By: Martin Liška <mliska@suse.cz>
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Signed-Off-By: Frank Ch. Eigler <fche@redhat.com>
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---
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debuginfod/ChangeLog | 6 ++++++
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debuginfod/debuginfod.cxx | 3 ++-
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2 files changed, 8 insertions(+), 1 deletion(-)
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diff --git a/debuginfod/debuginfod.cxx b/debuginfod/debuginfod.cxx
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index a089d0bd..9245be53 100644
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--- a/debuginfod/debuginfod.cxx
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+++ b/debuginfod/debuginfod.cxx
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@@ -1742,7 +1742,8 @@ handle_buildid_r_match (bool internal_req_p,
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if ((r == 0) && (fn != b_source1)) // stage 1
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continue;
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- if (fdcache.probe (b_source0, fn)) // skip if already interned
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+ if (fdcache.probe (b_source0, fn) && // skip if already interned
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+ fn != b_source1) // but only if we'd just be prefetching, PR29474
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continue;
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// extract this file to a temporary file
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--
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2.37.1
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