From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "James Morris" <jmorris@namei.org>,
"Sasha Levin" <sashal@kernel.org>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Linux MM" <linux-mm@kvack.org>,
linux-nvdimm <linux-nvdimm@lists.01.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Michal Hocko" <mhocko@suse.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"Keith Busch" <keith.busch@intel.com>,
"Vishal L Verma" <vishal.l.verma@intel.com>,
"Dave Jiang" <dave.jiang@intel.com>,
"Ross Zwisler" <zwisler@kernel.org>,
"Tom Lendacky" <thomas.lendacky@amd.com>,
"Huang, Ying" <ying.huang@intel.com>,
"Fengguang Wu" <fengguang.wu@intel.com>,
"Borislav Petkov" <bp@suse.de>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Yaowei Bai" <baiyaowei@cmss.chinamobile.com>,
"Takashi Iwai" <tiwai@suse.de>,
"Jérôme Glisse" <jglisse@redhat.com>
Subject: Re: [v1 2/2] device-dax: "Hotremove" persistent memory that is used like normal RAM
Date: Sat, 20 Apr 2019 13:01:51 -0400 [thread overview]
Message-ID: <CA+CK2bA-wDwRT5Gv2p9Nm1Vr8LNg84rQdE6=s2m2hQLYqj5Rog@mail.gmail.com> (raw)
In-Reply-To: <CAPcyv4jrxMNEEeUZZG3=CdkYSyX7OtJLv_ZQ1gbML7bscePiQA@mail.gmail.com>
> > Thank you for looking at this. Are you saying, that if drv.remove()
> > returns a failure it is simply ignored, and unbind proceeds?
>
> Yeah, that's the problem. I've looked at making unbind able to fail,
> but that can lead to general bad behavior in device-drivers. I.e. why
> spend time unwinding allocated resources when the driver can simply
> fail unbind? About the best a driver can do is make unbind wait on
> some event, but any return results in device-unbind.
Hm, just tested, and it is indeed so.
I see the following options:
1. Move hot remove code to some other interface, that can fail. Not
sure what that would be, but outside of unbind/remove_id. Any
suggestion?
2. Option two is don't attept to offline memory in unbind. Do
hot-remove memory in unbind if every section is already offlined.
Basically, do a walk through memblocks, and if every section is
offlined, also do the cleanup.
Pasha
next prev parent reply other threads:[~2019-04-20 17:02 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-20 15:31 [v1 0/2] "Hotremove" persistent memory Pavel Tatashin
2019-04-20 15:31 ` [v1 1/2] device-dax: fix memory and resource leak if hotplug fails Pavel Tatashin
2019-04-20 15:31 ` [v1 2/2] device-dax: "Hotremove" persistent memory that is used like normal RAM Pavel Tatashin
2019-04-20 16:18 ` Dan Williams
2019-04-20 16:30 ` Pavel Tatashin
2019-04-20 16:36 ` Dan Williams
2019-04-20 17:01 ` Pavel Tatashin [this message]
2019-04-20 21:02 ` Dan Williams
2019-04-20 22:04 ` Pavel Tatashin
2019-04-20 23:19 ` Dan Williams
2019-04-20 16:34 ` [v1 0/2] "Hotremove" persistent memory Dan Williams
2019-04-20 16:56 ` Pavel Tatashin
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