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Date: Wed, 5 Dec 2018 19:08:18 -0800
From: Davidlohr Bueso <dave@stgolabs.net>
To: Jason Baron <jbaron@akamai.com>
Cc: Roman Penyaev <rpenyaev@suse.de>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        akpm@linux-foundation.org
Subject: Re: [RFC PATCH 1/1] epoll: use rwlock in order to reduce
 ep_poll_callback() contention
Message-ID: <20181206030818.vu5g3edwl67tg3lc@linux-r8p5>
References: <20181203110237.14787-1-rpenyaev@suse.de>
 <45bce871-edfd-c402-acde-2e57e80cc522@akamai.com>
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>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.

Thanks,
Davidlohr