From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: 'GNU C Library' <libc-alpha@sourceware.org>
Subject: Re: [PATCH] elf: Use C11 like atomics on _dl_mcount
Date: Thu, 1 Sep 2022 14:19:24 +0000 [thread overview]
Message-ID: <AS4PR08MB79010433FBB113D4FC548413837B9@AS4PR08MB7901.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <59b9367c-08f1-4f38-7273-b5eca48be60e@linaro.org>
Hi Adhemerval,
> Right, I was not trying to be clever here and acquire might be a more
> strict memory order.
>
> And I haven't replied yet to you atomic refactor, but I also think changing
> step by step is indeed better than changing all the atomic altogether.
Well that's what I did, I split into about 15-20 patches rather than a single one.
> Do you think using relaxed on all atomic is suffice here?
Indeed, adding acquire on these counters will not ensure correct memory ordering.
Note this particular code looks very unsafe - it is not clear to me how it blocks
other threads from accessing new elements before they are properly initialized.
Also the counters that are being updated atomically are read without atomic
accesses, so may get a cached value or something newer - you don't know.
Cheers,
Wilco
next prev parent reply other threads:[~2022-09-01 14:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 12:21 Wilco Dijkstra
2022-09-01 13:09 ` Adhemerval Zanella Netto
2022-09-01 14:19 ` Wilco Dijkstra [this message]
2022-09-01 15:30 ` Adhemerval Zanella Netto
2022-09-01 23:18 ` Wilco Dijkstra
2022-09-02 12:21 ` Adhemerval Zanella Netto
2022-09-02 13:27 ` Wilco Dijkstra
-- strict thread matches above, loose matches on Subject: below --
2022-08-31 18:14 Adhemerval Zanella
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