From: Bart Van Assche <bvanassche@acm.org>
To: Avri Altman <Avri.Altman@wdc.com>,
"daejun7.park@samsung.com" <daejun7.park@samsung.com>,
yongmyung lee <ymhungry.lee@samsung.com>,
"James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: ALIM AKHTAR <alim.akhtar@samsung.com>,
"asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
Zang Leigang <zangleigang@hisilicon.com>,
Avi Shchislowski <Avi.Shchislowski@wdc.com>,
Bean Huo <beanhuo@micron.com>,
"cang@codeaurora.org" <cang@codeaurora.org>,
"stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
MOHAMMED RAFIQ KAMAL BASHA <md.rafiq@samsung.com>,
Sang-yoon Oh <sangyoon.oh@samsung.com>,
Jinyoung CHOI <j-young.choi@samsung.com>,
Adel Choi <adel.choi@samsung.com>,
BoRam Shin <boram.shin@samsung.com>,
Sung-Jun Park <sungjun07.park@samsung.com>
Subject: Re: Another approach of UFSHPB
Date: Tue, 26 May 2020 10:03:59 -0700 [thread overview]
Message-ID: <fd8c4336-8528-19d9-b1fe-1f74baf6b483@acm.org> (raw)
In-Reply-To: <SN6PR04MB46400AED930A3DC5B94AED25FCB00@SN6PR04MB4640.namprd04.prod.outlook.com>
On 2020-05-25 23:15, Avri Altman wrote:
>> On 2020-05-24 22:40, Daejun Park wrote:
>>> The HPB driver is close to the UFS core function, but it is not essential
>>> for operating UFS device. With reference to this article
>>> (https://lwn.net/Articles/645810/), we implemented extended UFS-feature
>>> as bus model. Because the HPB driver consumes the user's main memory, it
>> should
>>> support bind / unbind functionality as needed. We implemented the HPB
>> driver
>>> can be unbind / unload on runtime.
>>
>> I do not agree that the bus model is the best choice for freeing cache
>> memory if it is no longer needed. A shrinker is probably a much better
>> choice because the callback functions in a shrinker get invoked when a
>> system is under memory pressure. See also register_shrinker(),
>> unregister_shrinker() and struct shrinker in include/linux/shrinker.h.
>
> Since this discussion is closely related to cache allocation,
> What is your opinion about allocating the pages dynamically as the regions
> Are being activated/deactivated, in oppose of how it is done today -
> Statically on init for the entire max-active-subregions?
Memory that is statically allocated cannot be used for any other purpose
(e.g. page cache) without triggering the associated shrinker. As far as
I know shrinkers are only triggered when (close to) out of memory. So
dynamically allocating memory as needed is probably a better strategy
than statically allocating the entire region at initialization time.
Thanks,
Bart.
next prev parent reply other threads:[~2020-05-26 17:04 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 10:30 [RFC PATCH 00/13] scsi: ufs: Add HPB Support Avri Altman
2020-05-15 10:30 ` [RFC PATCH 01/13] scsi: ufs: Add HPB parameters Avri Altman
2020-05-15 10:30 ` [RFC PATCH 02/13] scsi: ufshpb: Init part I - Read HPB config Avri Altman
2020-05-15 15:33 ` Randy Dunlap
2020-05-16 1:46 ` Bart Van Assche
2020-05-16 1:57 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 03/13] scsi: scsi_dh: Introduce scsi_dh_ufshpb Avri Altman
2020-05-16 1:48 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 04/13] scsi: ufs: ufshpb: Init part II - Attach scsi device Avri Altman
2020-05-16 1:52 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 05/13] scsi: ufs: ufshpb: Disable HPB if no HPB-enabled luns Avri Altman
2020-05-16 2:02 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 06/13] scsi: scsi_dh: ufshpb: Prepare for L2P cache management Avri Altman
2020-05-16 2:13 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 07/13] scsi: scsi_dh: ufshpb: Add ufshpb state machine Avri Altman
2020-05-16 2:44 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 08/13] scsi: dh: ufshpb: Activate pinned regions Avri Altman
2020-05-15 10:30 ` [RFC PATCH 09/13] scsi: ufshpb: Add response API Avri Altman
2020-05-16 3:06 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 10/13] scsi: dh: ufshpb: Add ufshpb_set_params Avri Altman
2020-05-15 10:30 ` [RFC PATCH 11/13] scsi: Allow device handler set their own CDB Avri Altman
2020-05-16 3:19 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 12/13] scsi: dh: ufshpb: Add prep_fn handler Avri Altman
2020-05-16 3:40 ` Bart Van Assche
2020-05-15 10:30 ` [RFC PATCH 13/13] scsi: scsi_dh: ufshpb: Add "Cold" subregions timer Avri Altman
2020-05-16 3:50 ` [RFC PATCH 00/13] scsi: ufs: Add HPB Support Bart Van Assche
2020-05-16 9:14 ` Avri Altman
2020-05-16 17:14 ` Bart Van Assche
[not found] ` <CGME20200516171420epcas2p108c570904c5117c3654d71e0a2842faa@epcms2p7>
2020-05-19 22:31 ` Another approach of UFSHPB yongmyung lee
2020-05-20 17:55 ` Christoph Hellwig
2020-05-20 21:19 ` Bart Van Assche
2020-05-22 16:35 ` Bart Van Assche
2020-05-22 16:49 ` Bart Van Assche
[not found] ` <CGME20200516171420epcas2p108c570904c5117c3654d71e0a2842faa@epcms2p4>
2020-05-25 5:40 ` Daejun Park
2020-05-25 14:56 ` Bart Van Assche
2020-05-26 6:15 ` Avri Altman
2020-05-26 17:03 ` Bart Van Assche [this message]
[not found] ` <CGME20200516171420epcas2p108c570904c5117c3654d71e0a2842faa@epcms2p3>
2020-05-27 9:11 ` Daejun Park
2020-05-27 11:46 ` Bean Huo
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