From: Jens Axboe <axboe@fb.com>
To: Dan Williams <dan.j.williams@intel.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>
Cc: "Jason B. Akers" <jason.b.akers@intel.com>,
IDE/ATA development list <linux-ide@vger.kernel.org>,
"Karkra, Kapil" <kapil.karkra@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-nvme@lists.infradead.org
Subject: Re: [RFC PATCH 0/5] Enable use of Solid State Hybrid Drives
Date: Thu, 30 Oct 2014 08:17:56 -0600 [thread overview]
Message-ID: <54524894.8040604@fb.com> (raw)
In-Reply-To: <CAPcyv4ggAXzWows0PayvspOX4aP9G0PmLDes+0Q+m6VXQcF9Mw@mail.gmail.com>
On 2014-10-29 22:19, Dan Williams wrote:
> I understand the desire to have per-io / per-inode xadvise()-style
> hints, but I don't see why not also include a per-pid capability?
>
> Per-pid was not "icky" for flashcache [1]. It let's you flag
> processes that should not pollute the cache, as well "cache warming"
> processes pre-loading sub-ranges of files that is awkward to do with a
> per-inode hint. Per-pid also allows hinting on behalf of other
> otherwise cache-unaware processes.
per-pid is imho fine as well, as long as it's not the primary interface.
I quite like how the io priority works in this regard. If the task has a
priority set, we use that. If you pass in something else, that overrides
the task set one.
per-pid allows you to modify how we treat applications without modifying
the application itself. This is handy for eg streamed backup and
similar, which is most likely why flashcache has it.
--
Jens Axboe
next prev parent reply other threads:[~2014-10-30 14:17 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-29 18:23 [RFC PATCH 0/5] Enable use of Solid State Hybrid Drives Jason B. Akers
2014-10-29 18:23 ` [RFC PATCH 1/5] block, ioprio: include caching advice via ionice Jason B. Akers
2014-10-29 19:02 ` Jeff Moyer
2014-10-29 21:07 ` Dan Williams
2014-10-29 18:23 ` [RFC PATCH 2/5] block: ioprio hint to low-level device drivers Jason B. Akers
2014-10-29 18:23 ` [RFC PATCH 3/5] block: untangle ioprio from BLK_CGROUP and BLK_DEV_THROTTLING Jason B. Akers
2014-10-29 18:24 ` [RFC PATCH 4/5] block, mm: Added the necessary plumbing to take ioprio hints down to block layer Jason B. Akers
2014-10-29 18:24 ` [RFC PATCH 5/5] libata: Enabling Solid State Hybrid Drives (SSHDs) based on SATA 3.2 standard Jason B. Akers
2014-10-29 20:14 ` [RFC PATCH 0/5] Enable use of Solid State Hybrid Drives Dave Chinner
2014-10-29 21:10 ` Jens Axboe
2014-10-29 22:09 ` Dave Chinner
2014-10-29 22:24 ` Dan Williams
2014-10-30 7:21 ` Dave Chinner
2014-10-30 14:15 ` Jens Axboe
2014-10-30 17:07 ` Dan Williams
2014-11-10 4:22 ` Dave Chinner
2014-11-12 16:47 ` Dan Williams
2014-10-29 22:49 ` Jens Axboe
2014-10-29 21:11 ` Dan Williams
2014-12-03 15:25 ` Pavel Machek
2014-10-30 2:05 ` Martin K. Petersen
2014-10-30 2:35 ` Jens Axboe
2014-10-30 3:28 ` Martin K. Petersen
2014-10-30 4:19 ` Dan Williams
2014-10-30 14:17 ` Jens Axboe [this message]
2014-10-30 14:53 ` Jens Axboe
2014-10-30 16:27 ` Dan Williams
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