linux-kernel - Re: [PATCH v2] fs/dcache.c: avoid soft-lockup in dput()

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Date:	Wed, 6 Jul 2016 10:36:25 +0800
From:	Wei Fang <fangwei1@...wei.com>
To:	Boqun Feng <boqun.feng@...il.com>
CC:	<viro@...iv.linux.org.uk>, <linux-fsdevel@...r.kernel.org>,
	<akpm@...ux-foundation.org>, <jack@...e.com>, <axboe@...nel.dk>,
	<tj@...nel.org>, <linux-kernel@...r.kernel.org>,
	<stable@...r.kernel.org>
Subject: Re: [PATCH v2] fs/dcache.c: avoid soft-lockup in dput()

Hi, Boqun,

>> diff --git a/fs/dcache.c b/fs/dcache.c
>> index d5ecc6e..074fc1c 100644
>> --- a/fs/dcache.c
>> +++ b/fs/dcache.c
>> @@ -578,7 +578,7 @@ static struct dentry *dentry_kill(struct dentry *dentry)
>>  
>>  failed:
>>  	spin_unlock(&dentry->d_lock);
>> -	cpu_relax();
>> +	cond_resched();
> 
> Is it better to put the cond_resched() in the caller(i.e. dput()), right
> before "goto repeat"? Because it's obviously a loop there, which makes
> the purpose of cond_resched() more straightforward.

Agreed, that's more reasonable. I'll send v3 soon.

Thanks,
Wei