From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 20 Jun 2019 14:53:11 +0300
From: Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: [tarantool-patches] [PATCH v4 2/9] core: latch_steal routine
Message-ID: <20190620115311.ste2aez4rmqbmfln@esperanza>
References: <cover.1560978655.git.georgy@tarantool.org>
 <de30d3057f97c2f28449f8d3b448dbbe486a6c1b.1560978655.git.georgy@tarantool.org>
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In-Reply-To: <de30d3057f97c2f28449f8d3b448dbbe486a6c1b.1560978655.git.georgy@tarantool.org>
To: Georgy Kirichenko <georgy@tarantool.org>
Cc: tarantool-patches@freelists.org
List-ID: <tarantool-patches.dev.tarantool.org>

On Thu, Jun 20, 2019 at 12:23:09AM +0300, Georgy Kirichenko wrote:
> Allow to steal locked latch ownership for fiber which isn't owner
> of the latch. This is required to process transaction triggers
> asynchronously.
> 
> Prerequisites: #1254
> ---
>  src/lib/core/latch.h | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/src/lib/core/latch.h b/src/lib/core/latch.h
> index 49c59cf63..580942564 100644
> --- a/src/lib/core/latch.h
> +++ b/src/lib/core/latch.h
> @@ -155,6 +155,16 @@ latch_trylock(struct latch *l)
>  	return latch_lock_timeout(l, 0);
>  }
>  
> +/**
> + * Take a latch ownership
> + */
> +static inline void
> +latch_steal(struct latch *l)
> +{
> +	assert(l->owner != NULL);
> +	l->owner = fiber();
> +}
> +

Please try not to introduce dead code. This patch should be squashed
into the one that actually uses latch_steal IMO.