netdev - Re: [PATCH 1/3] rhashtable: use cmpxchg() in nested_table

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Message-ID: <20190320054109.6abodcm4yyhacc5w@gondor.apana.org.au>
Date:   Wed, 20 Mar 2019 13:41:09 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     NeilBrown <neilb@...e.com>
Cc:     Thomas Graf <tgraf@...g.ch>, netdev@...r.kernel.org,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] rhashtable: use cmpxchg() in nested_table_alloc()

On Fri, Mar 15, 2019 at 05:51:55PM +1100, NeilBrown wrote:
>
> I hoped the patch could be justified on the basis that the current
> behaviour is fragile - the dependency that a single spin lock covers a
> while slot (and all children) in the top-level nested table is not at
> all obvious.
> 
> I do have a stronger reason though - I want the replace the spinlocks
> with bit-spin-locks.  With those we will only hold a lock for the
> particular chain being worked on.  If you need that extra explanation to
> justify the patch, I'll hold it over until the other two patches land
> and the rest of the bit-spin-lock series is ready.

I think it would make more sense to combine this patch with your
bit-spin-lock patch in a series.

Thanks,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt