From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz,
mhocko@suse.com, david@redhat.com, osalvador@suse.de,
dan.j.williams@intel.com, sashal@kernel.org,
tyhicks@linux.microsoft.com, iamjoonsoo.kim@lge.com,
mike.kravetz@oracle.com, rostedt@goodmis.org, mingo@redhat.com,
jgg@ziepe.ca, peterz@infradead.org, mgorman@suse.de,
willy@infradead.org, rientjes@google.com, jhubbard@nvidia.com,
linux-doc@vger.kernel.org, ira.weiny@intel.com,
linux-kselftest@vger.kernel.org, jmorris@namei.org
Subject: [PATCH v8 10/14] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning
Date: Mon, 25 Jan 2021 14:47:47 -0500 [thread overview]
Message-ID: <20210125194751.1275316-11-pasha.tatashin@soleen.com> (raw)
In-Reply-To: <20210125194751.1275316-1-pasha.tatashin@soleen.com>
Document the special handling of page pinning when ZONE_MOVABLE present.
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
---
Documentation/admin-guide/mm/memory-hotplug.rst | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst
index 5c4432c96c4b..c6618f99f765 100644
--- a/Documentation/admin-guide/mm/memory-hotplug.rst
+++ b/Documentation/admin-guide/mm/memory-hotplug.rst
@@ -357,6 +357,15 @@ creates ZONE_MOVABLE as following.
Unfortunately, there is no information to show which memory block belongs
to ZONE_MOVABLE. This is TBD.
+.. note::
+ Techniques that rely on long-term pinnings of memory (especially, RDMA and
+ vfio) are fundamentally problematic with ZONE_MOVABLE and, therefore, memory
+ hot remove. Pinned pages cannot reside on ZONE_MOVABLE, to guarantee that
+ memory can still get hot removed - be aware that pinning can fail even if
+ there is plenty of free memory in ZONE_MOVABLE. In addition, using
+ ZONE_MOVABLE might make page pinning more expensive, because pages have to be
+ migrated off that zone first.
+
.. _memory_hotplug_how_to_offline_memory:
How to offline memory
--
2.25.1
next prev parent reply other threads:[~2021-01-25 20:38 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-25 19:47 [PATCH v8 00/14] prohibit pinning pages in ZONE_MOVABLE Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 01/14] mm/gup: don't pin migrated cma pages in movable zone Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 02/14] mm/gup: check every subpage of a compound page during isolation Pavel Tatashin
2021-02-03 13:22 ` Joao Martins
2021-02-03 14:51 ` Pavel Tatashin
2021-02-03 14:51 ` Pavel Tatashin
2021-02-03 15:32 ` Joao Martins
2021-02-03 16:46 ` Joao Martins
2021-02-03 14:53 ` Jason Gunthorpe
2021-02-03 16:13 ` Joao Martins
2021-02-03 18:00 ` Jason Gunthorpe
2021-01-25 19:47 ` [PATCH v8 03/14] mm/gup: return an error on migration failure Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 04/14] mm/gup: check for isolation errors Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 05/14] mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 06/14] mm: apply per-task gfp constraints in fast path Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 07/14] mm: honor PF_MEMALLOC_PIN for all movable pages Pavel Tatashin
[not found] ` <20210131130903.4875-1-lecopzer@gmail.com>
2021-01-31 16:03 ` Pavel Tatashin
2021-01-31 16:03 ` Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 08/14] mm/gup: do not migrate zero page Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 09/14] mm/gup: migrate pinned pages out of movable zone Pavel Tatashin
2021-01-25 19:47 ` Pavel Tatashin [this message]
2021-01-25 19:47 ` [PATCH v8 11/14] mm/gup: change index type to long as it counts pages Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 12/14] mm/gup: longterm pin migration cleanup Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 13/14] selftests/vm: gup_test: fix test flag Pavel Tatashin
2021-01-25 19:47 ` [PATCH v8 14/14] selftests/vm: gup_test: test faulting in kernel, and verify pinnable pages Pavel Tatashin
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=20210125194751.1275316-11-pasha.tatashin@soleen.com \
--to=pasha.tatashin@soleen.com \
--cc=akpm@linux-foundation.org \
--cc=dan.j.williams@intel.com \
--cc=david@redhat.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=ira.weiny@intel.com \
--cc=jgg@ziepe.ca \
--cc=jhubbard@nvidia.com \
--cc=jmorris@namei.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=mingo@redhat.com \
--cc=osalvador@suse.de \
--cc=peterz@infradead.org \
--cc=rientjes@google.com \
--cc=rostedt@goodmis.org \
--cc=sashal@kernel.org \
--cc=tyhicks@linux.microsoft.com \
--cc=vbabka@suse.cz \
--cc=willy@infradead.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.