From: David Hildenbrand <david@redhat.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: mhocko@kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, vbabka@suse.cz, pasha.tatashin@soleen.com
Subject: Re: [RFC PATCH v3 4/4] mm,memory_hotplug: Add mhp_memmap_on_memory boot option
Date: Wed, 2 Dec 2020 10:42:18 +0100 [thread overview]
Message-ID: <1cb78e59-d97c-f252-7d1b-e8e9bad38ddd@redhat.com> (raw)
In-Reply-To: <20201201115158.22638-5-osalvador@suse.de>
On 01.12.20 12:51, Oscar Salvador wrote:
> Self stored memmap leads to a sparse memory situation which is unsuitable
> for workloads that requires large contiguous memory chunks.
>
> Make this an opt-in which needs to be explicitly enabled.
>
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> ---
> mm/memory_hotplug.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 4b4708512f82..858d6161e915 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -42,6 +42,8 @@
> #include "internal.h"
> #include "shuffle.h"
>
> +static bool memmap_on_memory_enabled __read_mostly = false;
> +
> /*
> * online_page_callback contains pointer to current page onlining function.
> * Initially it is generic_online_page(). If it is required it could be
> @@ -1034,7 +1036,7 @@ bool __weak arch_support_memmap_on_memory(void)
>
> bool mhp_supports_memmap_on_memory(unsigned long size)
> {
> - if (!arch_support_memmap_on_memory() ||
> + if (!memmap_on_memory_enabled || !arch_support_memmap_on_memory() ||
> !IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP) ||
> size > memory_block_size_bytes())
> return false;
> @@ -1422,6 +1424,13 @@ static int __init cmdline_parse_movable_node(char *p)
> }
> early_param("movable_node", cmdline_parse_movable_node);
>
> +static int __init cmdline_parse_memmap_on_memory(char *p)
> +{
> + memmap_on_memory_enabled = true;
> + return 0;
> +}
> +early_param("mhp_memmap_on_memory", cmdline_parse_memmap_on_memory);
> +
> /* check which state of node_states will be changed when offline memory */
> static void node_states_check_changes_offline(unsigned long nr_pages,
> struct zone *zone, struct memory_notify *arg)
>
I have another memhp tunable in the works. I suggest doing it like
page_shuffling and using, module parameters instead. Makes this
a bit nicer IMHO.
diff --git a/mm/Makefile b/mm/Makefile
index 069f216e109e..ba7714b5eaa1 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
@@ -82,7 +86,6 @@ obj-$(CONFIG_SLAB) += slab.o
obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_KASAN) += kasan/
obj-$(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
The you can just use module_param/MODULE_PARM_DESC and set the parameter via
"memory_hotplug.memmap_on_memory"
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2020-12-02 9:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 11:51 [RFC PATCH v3 0/4] Allocate memmap from hotadded memory (per device) Oscar Salvador
2020-12-01 11:51 ` [RFC PATCH v3 1/4] mm,memory_hotplug: Add mhp_supports_memmap_on_memory Oscar Salvador
2020-12-02 9:36 ` David Hildenbrand
2020-12-09 9:36 ` Oscar Salvador
2020-12-09 9:40 ` David Hildenbrand
2020-12-09 9:43 ` Oscar Salvador
2020-12-01 11:51 ` [RFC PATCH v3 2/4] mm,memory_hotplug: Allocate memmap from the added memory range Oscar Salvador
2020-12-02 10:05 ` David Hildenbrand
2020-12-09 10:32 ` Oscar Salvador
2020-12-09 11:51 ` Oscar Salvador
2020-12-01 11:51 ` [RFC PATCH v3 3/4] mm,memory_hotplug: Enable MHP_MEMMAP_ON_MEMORY when supported Oscar Salvador
2020-12-02 9:37 ` David Hildenbrand
2020-12-09 9:38 ` Oscar Salvador
2020-12-01 11:51 ` [RFC PATCH v3 4/4] mm,memory_hotplug: Add mhp_memmap_on_memory boot option Oscar Salvador
2020-12-02 9:42 ` David Hildenbrand [this message]
2020-12-09 10:02 ` Oscar Salvador
2020-12-09 10:04 ` David Hildenbrand
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