linux-kernel - Re: [PATCH] mm: introduce arg_lock to protect arg_start|end and env_start|end in mm

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Message-ID: <aed7f679-a32f-d8d7-eb59-ec05fc49a70e@linux.alibaba.com>
Date:   Sat, 24 Mar 2018 17:32:24 -0700
From:   Yang Shi <yang.shi@...ux.alibaba.com>
To:     Matthew Wilcox <willy@...radead.org>
Cc:     adobriyan@...il.com, mhocko@...nel.org, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: introduce arg_lock to protect arg_start|end and
 env_start|end in mm_struct



On 3/23/18 9:30 PM, Matthew Wilcox wrote:
>> So, introduce a new rwlock in mm_struct to protect the concurrent access
>> to arg_start|end and env_start|end.
> I don't think an rwlock makes much sense here.  There is almost no
> concurrency on the read side, and an rwlock is more expensive than
> a spinlock.  Just use a spinlock.

Thanks for the comment. Yes, actually there is not concurrency on the 
read side, will change to regular spin lock.

Yang