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Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering ass
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions |
Date: |
Wed, 13 Jul 2016 09:36:01 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 |
On 13/07/2016 01:19, Emilio G. Cota wrote:
> I wouldn't put those comments in the source--seqlock callers should
> know what they're doing, and what barriers seqlocks imply.
In general I'd agree with you, however in this case the "begin" calls
are what implements QHT's guarantee *for the caller*, so I think it's
worth having the comments. In other words, if for any reason you do
anything before the read_begin and write_begin you still have to provide
barrier semantics. It's not an explanation, it's a protection against
future mistakes.
There's no need for such comment at read_retry and write_end callsites,
though.
Also, it's spelled "guarantee". :)
Paolo
> I'm OK with stating what the implied ordering is in the header
> file, though.
Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions, Paolo Bonzini, 2016/07/13
Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions, Sergey Fedorov, 2016/07/15
Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions, Paolo Bonzini, 2016/07/15
Re: [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions, Sergey Fedorov, 2016/07/15
[Qemu-devel] [PATCH v3 03/11] tcg: Prepare safe tb_jmp_cache lookup out of tb_lock, Sergey Fedorov, 2016/07/12