linux-kernel - Re: [PATCH 7/8] wbt: add general throttling mechanism

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Message-ID: <b983e71b-c959-ca43-ce7b-b234db6035fa@fb.com>
Date:   Thu, 1 Sep 2016 12:51:49 -0600
From:   Jens Axboe <axboe@...com>
To:     Omar Sandoval <osandov@...ndov.com>
CC:     <axboe@...nel.dk>, <linux-kernel@...r.kernel.org>,
        <linux-fsdevel@...r.kernel.org>, <linux-block@...r.kernel.org>
Subject: Re: [PATCH 7/8] wbt: add general throttling mechanism

On 09/01/2016 12:05 PM, Omar Sandoval wrote:
>> diff --git a/lib/Kconfig b/lib/Kconfig
>> index d79909dc01ec..5a65a1f91889 100644
>> --- a/lib/Kconfig
>> +++ b/lib/Kconfig
>> @@ -550,4 +550,8 @@ config STACKDEPOT
>>  	bool
>>  	select STACKTRACE
>>
>> +config WBT
>> +	bool
>> +	select SCALE_BITMAP
>
> Looks like this snuck in from your experiments to get this to work on
> top of scale_bitmap?

Oops yes, it is indeed. Killed, thanks.

>> +	if (waitqueue_active(&rwb->wait)) {
>> +		int diff = limit - inflight;
>> +
>> +		if (!inflight || diff >= rwb->wb_background / 2)
>> +			wake_up_nr(&rwb->wait, 1);
>
> wake_up(&rwb->wait)?

Yeah, that'd be cleaner. I think this is a leftover from when I 
experimented with batched wakeups, with nr != 1. I'll change it to just 
wake_up().

-- 
Jens Axboe