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From: "Dilger, Andreas" <andreas.dilger@intel.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	NeilBrown <neilb@suse.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Drokin, Oleg" <oleg.drokin@intel.com>,
	"Siyao, Lai" <lai.siyao@intel.com>,
	Lustre Development List <lustre-devel@lists.lustre.org>
Subject: Re: [PATCH 4/4] staging: lustre: obdclass: change object lookup to no wait mode
Date: Wed, 16 May 2018 09:12:32 +0000	[thread overview]
Message-ID: <EDCE6E68-0B5C-4F82-B356-8D70AE5FF92A@intel.com> (raw)
In-Reply-To: <20180516080022.b4ihz7opiueobm7u@mwanda>

On May 16, 2018, at 02:00, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> 
> On Tue, May 15, 2018 at 04:02:55PM +0100, James Simmons wrote:
>> 
>>>> 	/*
>>>> 	 * Allocate new object. This may result in rather complicated
>>>> 	 * operations, including fld queries, inode loading, etc.
>>>> 	 */
>>>> 	o = lu_object_alloc(env, dev, f, conf);
>>>> -	if (IS_ERR(o))
>>>> +	if (unlikely(IS_ERR(o)))
>>>> 		return o;
>>>> 
>>> 
>>> This is an unrelated and totally pointless.  likely/unlikely annotations
>>> hurt readability, and they should only be added if it's something which
>>> is going to show up in benchmarking.  lu_object_alloc() is already too
>>> slow for the unlikely() to make a difference and anyway IS_ERR() has an
>>> unlikely built in so it's duplicative...
>> 
>> Sounds like a good checkpatch case to test for :-)
> 
> The likely/unlikely annotations have their place in fast paths so a
> checkpatch warning would get annoying...

I think James was suggesting a check for unlikely(IS_ERR()), or possibly
a check for unlikely() on something that is already unlikely() after CPP
expansion.

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel Corporation







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  reply	other threads:[~2018-05-16  9:12 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-02 18:21 [PATCH 0/4] staging: lustre: obdclass: missing lu_object fixes James Simmons
2018-05-02 18:21 ` [PATCH 1/4] staging: lustre: obdclass: change spinlock of key to rwlock James Simmons
2018-05-03 13:50   ` David Laight
2018-05-03 23:26     ` NeilBrown
2018-05-04  0:11     ` Dilger, Andreas
2018-05-04  0:53       ` NeilBrown
2018-05-02 18:21 ` [PATCH 2/4] staging: lustre: obdclass: hoist locking in lu_context_exit() James Simmons
2018-05-02 18:21 ` [PATCH 3/4] staging: lustre: obdclass: guarantee all keys filled James Simmons
2018-05-02 18:21 ` [PATCH 4/4] staging: lustre: obdclass: change object lookup to no wait mode James Simmons
2018-05-04  1:15   ` NeilBrown
2018-05-15  0:37     ` James Simmons
2018-05-15  1:37       ` NeilBrown
2018-05-15  2:11         ` James Simmons
2018-05-07  1:47   ` Greg Kroah-Hartman
2018-05-08 11:45   ` Dan Carpenter
2018-05-15 15:02     ` James Simmons
2018-05-16  8:00       ` Dan Carpenter
2018-05-16  9:12         ` Dilger, Andreas [this message]
2018-05-16 15:44           ` Joe Perches
2018-05-16 16:57       ` Greg Kroah-Hartman
2018-05-17  5:07         ` James Simmons

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