[Bug debuginfod/27983] ignore duplicate urls
Wed Jul 14 16:36:13 GMT 2021
On Fri, Jul 09, 2021 at 03:12:18PM -0400, Noah Sanci via Elfutils-devel wrote:
> From e37f49a0fd5f27907584b19336cd250d825acc98 Mon Sep 17 00:00:00 2001
> From: Noah Sanci <email@example.com>
> Date: Fri, 9 Jul 2021 14:53:10 -0400
> Subject: [PATCH] debuginfod: PR27983 - ignore duplicate urls
> Gazing at server logs, one sees a minority of clients who appear to have
> duplicate query traffic coming in: the same URL, milliseconds apart.
> Chances are the user accidentally doubled her $DEBUGINFOD_URLS somehow,
> and the client library is dutifully asking the servers TWICE. Bug #27863
> reduces the pain on the servers' CPU, but dupe network traffic is still
> being paid. We should reject sending outright duplicate concurrent
> Signed-off-by: Noah Sanci <firstname.lastname@example.org>
> debuginfod/ChangeLog | 7 +++++
> debuginfod/debuginfod-client.c | 56 +++++++++++++++++++++++++---------
> tests/ChangeLog | 5 +++
> tests/run-debuginfod-find.sh | 13 ++++++++
> 4 files changed, 67 insertions(+), 14 deletions(-)
> diff --git a/debuginfod/ChangeLog b/debuginfod/ChangeLog
> index d9d11737..24ccb8ef 100644
> --- a/debuginfod/ChangeLog
> +++ b/debuginfod/ChangeLog
> @@ -1,3 +1,10 @@
> +2021-07-09 Noah Sanci <email@example.com>
> + * debuginfod-client.c (debuginfod_query_server): As full-length
> + urls are generated with standardized formats, ignore duplicates.
> + Also update the number of urls to the unduplicated number of
> + urls.
You deduplicate the full URLs after they are fully constructed. Would
it make sense to do the deduplication on server_url, maybe even as
part of the Count number of URLs code? That might make the code
simpler. And you can change num_urls upfront.
> + num_urls = unduplicated_urls;
> + data = reallocarray( (void *) data, num_urls, sizeof(struct handle_data));
Maybe this reallocarray is unnecessary. Yes, it might save a little
bit of memory, but you do have to handle reallocarray failure.
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