linux-kernel - Re: [RFC PATCH 1/1] epoll: use rwlock in order to reduce ep_poll

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Message-ID: <51d9ca4acbbdb17a390383b839f1aba0@suse.de>
Date:   Thu, 06 Dec 2018 11:27:36 +0100
From:   Roman Penyaev <rpenyaev@...e.de>
To:     Davidlohr Bueso <dave@...olabs.net>
Cc:     Jason Baron <jbaron@...mai.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        akpm@...ux-foundation.org
Subject: Re: [RFC PATCH 1/1] epoll: use rwlock in order to reduce
 ep_poll_callback() contention

On 2018-12-06 04:08, Davidlohr Bueso wrote:
>> On 12/3/18 6:02 AM, Roman Penyaev wrote:
> 
>>>  		if (!ep_is_linked(epi)) {
>>> -			list_add_tail(&epi->rdllink, &ep->rdllist);
>>> +			/* Reverse ->ovflist, events should be in FIFO */
>>> +			list_add(&epi->rdllink, &ep->rdllist);
>>>  			ep_pm_stay_awake(epi);
>>>  		}
> 
> This should probably a separate patch as it fixes the ordering,
> regardless of the rwlock+xchg optimization.

Yes, should not be a part of this RFC.  Thanks.

--
Roman