From: Oscar Salvador <osalvador@suse.de>
To: akpm@linux-foundation.org
Cc: david@redhat.com, mhocko@kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org, vbabka@suse.cz,
pasha.tatashin@soleen.com, Oscar Salvador <osalvador@suse.de>
Subject: [PATCH 5/5] mm,memory_hotplug: Add kernel boot option to enable memmap_on_memory
Date: Thu, 17 Dec 2020 14:07:58 +0100 [thread overview]
Message-ID: <20201217130758.11565-6-osalvador@suse.de> (raw)
In-Reply-To: <20201217130758.11565-1-osalvador@suse.de>
Self stored memmap leads to a sparse memory situation which is unsuitable
for workloads that requires large contiguous memory chunks, so make this
an opt-in which needs to be explicitly enabled.
To control this, let memory_hotplug have its own memory space, as suggested
by David, so we can add memory_hotplug.memmap_on_memory parameter.
Signed-off-by: Oscar Salvador <osalvador@suse.de>
---
.../admin-guide/kernel-parameters.txt | 14 ++++++++++++
mm/Makefile | 5 ++++-
mm/memory_hotplug.c | 22 ++++++++++++++++++-
3 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c722ec19cd00..8ff3d7c87165 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2776,6 +2776,20 @@
seconds. Use this parameter to check at some
other rate. 0 disables periodic checking.
+ memory_hotplug.memmap_on_memory
+ [KNL,X86,ARM,PPC] Boolean flag to enable this feature.
+ Format: {on | off (default)}
+ When enabled, memory to build the pages tables for the
+ memmap array describing the hot-added range will be taken
+ from the range itself, so the memmap page tables will be
+ self-hosted.
+ Since only single memory device ranges are supported at
+ the moment, this option is disabled by default because
+ it might have an impact on workloads that needs large
+ contiguous memory chunks.
+ The state of the flag can be read in
+ /sys/module/memory_hotplug/parameters/memmap_on_memory.
+
memtest= [KNL,X86,ARM,PPC] Enable memtest
Format: <integer>
default : 0 <disable>
diff --git a/mm/Makefile b/mm/Makefile
index 6b581f8337e8..0425cec6cb17 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -58,9 +58,13 @@ obj-y := filemap.o mempool.o oom_kill.o fadvise.o \
page-alloc-y := page_alloc.o
page-alloc-$(CONFIG_SHUFFLE_PAGE_ALLOCATOR) += shuffle.o
+# Give 'memory_hotplug' its own module-parameter namespace
+memory-hotplug-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
+
obj-y += page-alloc.o
obj-y += init-mm.o
obj-y += memblock.o
+obj-y += $(memory-hotplug-y)
ifdef CONFIG_MMU
obj-$(CONFIG_ADVISE_SYSCALLS) += madvise.o
@@ -83,7 +87,6 @@ obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_KASAN) += kasan/
obj-$(CONFIG_KFENCE) += kfence/
obj-$(CONFIG_FAILSLAB) += failslab.o
-obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_MEMTEST) += memtest.o
obj-$(CONFIG_MIGRATION) += migrate.o
obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9371e7d3f583..f5f95f49b98a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -42,7 +42,27 @@
#include "internal.h"
#include "shuffle.h"
-static bool memmap_on_memory_enabled;
+/*
+ * memory_hotplug.memmap_on_memory parameter
+ */
+static bool memmap_on_memory_enabled __ro_after_init;
+
+static int memmap_on_memory_show(char *buffer, const struct kernel_param *kp)
+{
+ return sprintf(buffer, "%s\n",
+ memmap_on_memory_enabled ? "on" : "off");
+}
+
+static __meminit int memmap_on_memory_store(const char *val,
+ const struct kernel_param *kp)
+{
+ if (!IS_ENABLED(CONFIG_ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE))
+ return -EINVAL;
+
+ return param_set_bool(val, kp);
+}
+module_param_call(memmap_on_memory, memmap_on_memory_store,
+ memmap_on_memory_show, &memmap_on_memory_enabled, 0400);
/*
* online_page_callback contains pointer to current page onlining function.
--
2.26.2
next prev parent reply other threads:[~2020-12-17 13:08 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-17 13:07 [PATCH 0/5] Allocate memmap from hotadded memory (per device) Oscar Salvador
2020-12-17 13:07 ` [PATCH 1/5] mm: Introduce ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE Oscar Salvador
2021-01-11 16:52 ` David Hildenbrand
2021-01-12 7:26 ` Oscar Salvador
2021-01-12 10:12 ` David Hildenbrand
2021-01-12 11:17 ` Oscar Salvador
2021-01-12 11:17 ` David Hildenbrand
2020-12-17 13:07 ` [PATCH 2/5] mm,memory_hotplug: Allocate memmap from the added memory range Oscar Salvador
2021-01-18 10:11 ` Oscar Salvador
2021-01-19 13:58 ` David Hildenbrand
2021-01-25 10:39 ` Oscar Salvador
2021-01-25 10:56 ` Oscar Salvador
2021-01-25 11:02 ` David Hildenbrand
2021-01-25 13:36 ` Oscar Salvador
2021-01-25 10:57 ` David Hildenbrand
2021-01-25 11:18 ` Oscar Salvador
2021-01-25 11:23 ` David Hildenbrand
2020-12-17 13:07 ` [PATCH 3/5] acpi,memhotplug: Enable MHP_MEMMAP_ON_MEMORY when supported Oscar Salvador
2021-01-11 16:53 ` David Hildenbrand
2020-12-17 13:07 ` [PATCH 4/5] powerpc/memhotplug: " Oscar Salvador
2021-01-11 16:55 ` David Hildenbrand
2021-01-12 13:31 ` Oscar Salvador
2020-12-17 13:07 ` Oscar Salvador [this message]
2021-01-11 9:05 ` [PATCH 0/5] Allocate memmap from hotadded memory (per device) Oscar Salvador
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