From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
jglisse@redhat.com, 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-mm@kvack.org,
ying.huang@intel.com, fengguang.wu@intel.com,
keith.busch@intel.com
Subject: [PATCH 2/5] mm/resource: move HMM pr_debug() deeper into resource code
Date: Mon, 25 Feb 2019 10:57:33 -0800 [thread overview]
Message-ID: <20190225185733.FB5686EB@viggo.jf.intel.com> (raw)
In-Reply-To: <20190225185727.BCBD768C@viggo.jf.intel.com>
From: Dave Hansen <dave.hansen@linux.intel.com>
HMM consumes physical address space for its own use, even
though nothing is mapped or accessible there. It uses a
special resource description (IORES_DESC_DEVICE_PRIVATE_MEMORY)
to uniquely identify these areas.
When HMM consumes address space, it makes a best guess about
what to consume. However, it is possible that a future memory
or device hotplug can collide with the reserved area. In the
case of these conflicts, there is an error message in
register_memory_resource().
Later patches in this series move register_memory_resource()
from using request_resource_conflict() to __request_region().
Unfortunately, __request_region() does not return the conflict
like the previous function did, which makes it impossible to
check for IORES_DESC_DEVICE_PRIVATE_MEMORY in a conflicting
resource.
Instead of warning in register_memory_resource(), move the
check into the core resource code itself (__request_region())
where the conflicting resource _is_ available. This has the
added bonus of producing a warning in case of HMM conflicts
with devices *or* RAM address space, as opposed to the RAM-
only warnings that were there previously.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Jerome Glisse <jglisse@redhat.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: linux-nvdimm@lists.01.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: Huang Ying <ying.huang@intel.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
---
b/kernel/resource.c | 9 +++++++++
b/mm/memory_hotplug.c | 5 -----
2 files changed, 9 insertions(+), 5 deletions(-)
diff -puN kernel/resource.c~move-request_region-check kernel/resource.c
--- a/kernel/resource.c~move-request_region-check 2019-02-25 10:56:48.581908031 -0800
+++ b/kernel/resource.c 2019-02-25 10:56:48.588908031 -0800
@@ -1132,6 +1132,15 @@ struct resource * __request_region(struc
conflict = __request_resource(parent, res);
if (!conflict)
break;
+ /*
+ * mm/hmm.c reserves physical addresses which then
+ * become unavailable to other users. Conflicts are
+ * not expected. Warn to aid debugging if encountered.
+ */
+ if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
+ pr_warn("Unaddressable device %s %pR conflicts with %pR",
+ conflict->name, conflict, res);
+ }
if (conflict != parent) {
if (!(conflict->flags & IORESOURCE_BUSY)) {
parent = conflict;
diff -puN mm/memory_hotplug.c~move-request_region-check mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~move-request_region-check 2019-02-25 10:56:48.583908031 -0800
+++ b/mm/memory_hotplug.c 2019-02-25 10:56:48.588908031 -0800
@@ -111,11 +111,6 @@ static struct resource *register_memory_
res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
conflict = request_resource_conflict(&iomem_resource, res);
if (conflict) {
- if (conflict->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) {
- pr_debug("Device unaddressable memory block "
- "memory hotplug at %#010llx !\n",
- (unsigned long long)start);
- }
pr_debug("System RAM resource %pR cannot be added\n", res);
kfree(res);
return ERR_PTR(-EEXIST);
_
next prev parent reply other threads:[~2019-02-25 19:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-25 18:57 [PATCH 0/5] [v5] Allow persistent memory to be used like normal RAM Dave Hansen
2019-02-25 18:57 ` [PATCH 1/5] mm/resource: return real error codes from walk failures Dave Hansen
2019-02-26 7:41 ` Christophe Leroy
2019-02-25 18:57 ` Dave Hansen [this message]
2019-02-25 18:57 ` [PATCH 3/5] mm/memory-hotplug: allow memory resources to be children Dave Hansen
2019-02-25 18:57 ` [PATCH 4/5] mm/resource: let walk_system_ram_range() search child resources Dave Hansen
2019-02-25 18:57 ` [PATCH 5/5] dax: "Hotplug" persistent memory for use like normal RAM Dave Hansen
2019-02-28 7:53 ` [PATCH 0/5] [v5] Allow persistent memory to be used " Dan Williams
-- strict thread matches above, loose matches on Subject: below --
2019-01-24 23:14 [PATCH 0/5] [v4] " Dave Hansen
2019-01-24 23:14 ` [PATCH 2/5] mm/resource: move HMM pr_debug() deeper into resource code Dave Hansen
2019-01-25 19:07 ` Jerome Glisse
2019-01-25 21:18 ` Bjorn Helgaas
2019-01-25 21:24 ` Dave Hansen
2019-01-29 1:34 ` Michael Ellerman
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=20190225185733.FB5686EB@viggo.jf.intel.com \
--to=dave.hansen@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=dave.jiang@intel.com \
--cc=fengguang.wu@intel.com \
--cc=jglisse@redhat.com \
--cc=keith.busch@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=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).