linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jerome Glisse <jglisse@redhat.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	dave@sr71.net, dan.j.williams@intel.com, dave.jiang@intel.com,
	zwisler@kernel.org, vishal.l.verma@intel.com,
	thomas.lendacky@amd.com, akpm@linux-foundation.org,
	mhocko@suse.com, linux-nvdimm@lists.01.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	ying.huang@intel.com, fengguang.wu@intel.com, bp@suse.de,
	bhelgaas@google.com, baiyaowei@cmss.chinamobile.com,
	tiwai@suse.de
Subject: Re: [PATCH 2/4] mm/memory-hotplug: allow memory resources to be children
Date: Fri, 18 Jan 2019 15:26:18 -0500	[thread overview]
Message-ID: <20190118202618.GB3060@redhat.com> (raw)
In-Reply-To: <c6df9b8d-571d-3b4f-c528-dc176f8577e2@intel.com>

On Fri, Jan 18, 2019 at 11:58:54AM -0800, Dave Hansen wrote:
> On 1/16/19 11:16 AM, Jerome Glisse wrote:
> >> We *could* also simply truncate the existing top-level
> >> "Persistent Memory" resource and take over the released address
> >> space.  But, this means that if we ever decide to hot-unplug the
> >> "RAM" and give it back, we need to recreate the original setup,
> >> which may mean going back to the BIOS tables.
> >>
> >> This should have no real effect on the existing collision
> >> detection because the areas that truly conflict should be marked
> >> IORESOURCE_BUSY.
> > 
> > Still i am worrying that this might allow device private to register
> > itself as a child of some un-busy resource as this patch obviously
> > change the behavior of register_memory_resource()
> > 
> > What about instead explicitly providing parent resource to add_memory()
> > and then to register_memory_resource() so if it is provided as an
> > argument (!NULL) then you can __request_region(arg_res, ...) otherwise
> > you keep existing code intact ?
> 
> We don't have the locking to do this, do we?  For instance, all the
> locking is done below register_memory_resource(), so any previous
> resource lookup is invalid by the time we get to register_memory_resource().

Yeah you are right, maybe just a bool then ? bool as_child

Cheers,
Jérôme

  reply	other threads:[~2019-01-18 20:26 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16 18:18 [PATCH 0/4] Allow persistent memory to be used like normal RAM Dave Hansen
2019-01-16 18:19 ` [PATCH 1/4] mm/resource: return real error codes from walk failures Dave Hansen
2019-01-16 20:38   ` Bjorn Helgaas
2019-01-16 18:19 ` [PATCH 2/4] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2019-01-16 19:16   ` Jerome Glisse
2019-01-16 23:01     ` Dave Hansen
2019-01-16 23:38       ` Jerome Glisse
2019-01-23 20:03         ` Dave Hansen
2019-01-23 20:15           ` Jerome Glisse
2019-01-18 19:58     ` Dave Hansen
2019-01-18 20:26       ` Jerome Glisse [this message]
2019-01-23 17:05   ` Michal Hocko
2019-01-16 18:19 ` [PATCH 3/4] dax/kmem: let walk_system_ram_range() search child resources Dave Hansen
2019-01-16 18:19 ` [PATCH 4/4] dax: "Hotplug" persistent memory for use like normal RAM Dave Hansen
2019-01-16 21:16   ` Bjorn Helgaas
2019-01-16 21:40     ` Dave Hansen
2019-01-16 21:44       ` Bjorn Helgaas
2019-01-16 22:06       ` Dan Williams
2019-01-16 21:53     ` Dave Hansen
2019-01-16 21:59       ` Bjorn Helgaas
2019-01-16 21:31   ` Dan Williams
2019-01-17  5:21   ` Du, Fan
2019-01-17 16:56     ` Dan Williams
2019-01-17  8:19   ` Yanmin Zhang
2019-01-17 15:17     ` Dave Hansen
2019-01-18  7:47       ` Yanmin Zhang
2019-01-18 15:20         ` Dave Hansen
2019-01-17 16:29 ` [PATCH 0/4] Allow persistent memory to be used " Jeff Moyer
2019-01-17 16:47   ` Keith Busch
2019-01-17 17:20     ` Jeff Moyer
2019-01-17 19:34       ` Keith Busch
2019-01-17 21:57         ` Jeff Moyer
2019-01-18 11:48       ` Fengguang Wu
2019-01-17 16:50   ` Dan Williams
2019-01-17 22:43   ` Dave Hansen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190118202618.GB3060@redhat.com \
    --to=jglisse@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=baiyaowei@cmss.chinamobile.com \
    --cc=bhelgaas@google.com \
    --cc=bp@suse.de \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=dave.jiang@intel.com \
    --cc=dave@sr71.net \
    --cc=fengguang.wu@intel.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=mhocko@suse.com \
    --cc=thomas.lendacky@amd.com \
    --cc=tiwai@suse.de \
    --cc=vishal.l.verma@intel.com \
    --cc=ying.huang@intel.com \
    --cc=zwisler@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).