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From: Junio C Hamano <gitster@pobox.com>
To: Randall Becker <randall.becker@nexbridge.ca>
Cc: Patrick Steinhardt <ps@pks.im>,
	 "git@vger.kernel.org" <git@vger.kernel.org>
Subject: Re: [PATCH 0/4] reftable: fix out-of-memory errors on NonStop
Date: Sat, 21 Dec 2024 09:43:33 -0800	[thread overview]
Message-ID: <xmqqy109aq4a.fsf@gitster.g> (raw)
In-Reply-To: <BL3PR17MB6020D6CB8712F2C6F36FC8CFF4002@BL3PR17MB6020.namprd17.prod.outlook.com> (Randall Becker's message of "Sat, 21 Dec 2024 15:05:44 +0000")

Randall Becker <randall.becker@nexbridge.ca> writes:

> Thank you for this series. I think the problem may not be limited
> only to NonStop based on the documented ambiguous behaviour of
> malloc.

Yes, an implementation is allowed to return NULL when asked to
allocate 0 bytes.  On the Git side, we sidestep the problem in
exactly the opposite way---our malloc() wrapper makes another
request to allocate 1-byte block after seeing NULL from a request
for 0-byte allocation.  The reftable code takes an approach to
eliminate the need to requiest 0-sized allocation in the first
place, which is an arguably more valid solution.

Thanks, both, for finding and fixing the issue.

  reply	other threads:[~2024-12-21 17:43 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-21 11:50 [PATCH 0/4] reftable: fix out-of-memory errors on NonStop Patrick Steinhardt
2024-12-21 11:50 ` [PATCH 1/4] reftable/stack: don't perform auto-compaction with less than two tables Patrick Steinhardt
2024-12-21 17:08   ` Junio C Hamano
2024-12-21 17:51     ` Junio C Hamano
2024-12-22  7:13       ` Patrick Steinhardt
2024-12-21 11:50 ` [PATCH 2/4] reftable/merged: fix zero-sized allocation when there are no readers Patrick Steinhardt
2024-12-21 12:40   ` Kristoffer Haugsbakk
2024-12-21 14:18     ` Patrick Steinhardt
2024-12-21 17:13     ` Junio C Hamano
2024-12-21 11:50 ` [PATCH 3/4] reftable/stack: " Patrick Steinhardt
2024-12-21 17:36   ` Junio C Hamano
2024-12-21 17:57     ` Junio C Hamano
2024-12-21 18:06       ` rsbecker
2024-12-21 18:30         ` Junio C Hamano
2024-12-22 17:48           ` rsbecker
2024-12-22 18:17           ` rsbecker
2024-12-22 18:35             ` Patrick Steinhardt
2024-12-23  4:08               ` Junio C Hamano
2024-12-22  7:13     ` Patrick Steinhardt
2024-12-21 11:50 ` [PATCH 4/4] reftable/basics: return NULL on zero-sized allocations Patrick Steinhardt
2024-12-21 12:53   ` Kristoffer Haugsbakk
2024-12-21 15:05 ` [PATCH 0/4] reftable: fix out-of-memory errors on NonStop Randall Becker
2024-12-21 17:43   ` Junio C Hamano [this message]
2024-12-21 16:52 ` Junio C Hamano
2024-12-22  7:24 ` [PATCH v2 " Patrick Steinhardt
2024-12-22  7:24   ` [PATCH v2 1/4] reftable/stack: don't perform auto-compaction with less than two tables Patrick Steinhardt
2024-12-22  7:24   ` [PATCH v2 2/4] reftable/merged: fix zero-sized allocation when there are no readers Patrick Steinhardt
2024-12-22  7:24   ` [PATCH v2 3/4] reftable/stack: " Patrick Steinhardt
2024-12-22  7:24   ` [PATCH v2 4/4] reftable/basics: return NULL on zero-sized allocations Patrick Steinhardt
2024-12-22 16:31   ` [PATCH v2 0/4] reftable: fix out-of-memory errors on NonStop Junio C Hamano

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