[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <4ae57faa-2f69-98cd-e276-1e091a6922b0@fb.com>
Date: Fri, 28 Oct 2016 08:57:07 -0600
From: Jens Axboe <axboe@...com>
To: Christoph Hellwig <hch@...radead.org>
CC: <axboe@...nel.dk>, <linux-kernel@...r.kernel.org>,
<linux-fsdevel@...r.kernel.org>, <linux-block@...r.kernel.org>,
<jack@...e.cz>, <kernel@...ivas.org>
Subject: Re: [PATCH 1/8] block: add WRITE_BG
On 10/27/2016 12:37 AM, Christoph Hellwig wrote:
>> * non-volatile media on completion.
>> + * WRITE_BG Background write. This is for background activity like
>> + * the periodic flush and background threshold writeback
>> *
>> */
>> #define RW_MASK REQ_OP_WRITE
>> @@ -202,6 +204,7 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
>> #define WRITE_FLUSH (REQ_SYNC | REQ_NOIDLE | REQ_PREFLUSH)
>> #define WRITE_FUA (REQ_SYNC | REQ_NOIDLE | REQ_FUA)
>> #define WRITE_FLUSH_FUA (REQ_SYNC | REQ_NOIDLE | REQ_PREFLUSH | REQ_FUA)
>> +#define WRITE_BG (REQ_NOIDLE | REQ_BG)
>
> I've been trying to kill off these WRITE_ flags as they aren't exactly
> helpful, see my branch here that I'm waiting for the previous serious to
> go in:
>
> http://git.infradead.org/users/hch/block.git/shortlog/refs/heads/block-flags
I'll just adapt to whatever goes in first, not really a concern for me.
> Which also begs the question why you add the REQ_NOIDLE flag above, as
> it's only applied to synchronous queues in cfq as far as I can tell.
Right, it's a CFQ hint. We only want to potentially idle for direct/sync
writes, not buffer async writeback.
> And while I'm at nitpicking about the most trivial patch of the
> series anyway: any good reason to not just spell out the "BACKGROUND" ?
Sure, I can make that change.
--
Jens Axboe
Powered by blists - more mailing lists