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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id af79cd13be357-7b9ac2bc86asm158342685a.16.2024.12.20.10.31.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2024 10:31:06 -0800 (PST) From: Gregory Price To: linux-mm@kvack.org Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, kernel-team@meta.com, corbet@lwn.net, david@redhat.com, osalvador@suse.de, akpm@linux-foundation.org, chenhuacai@kernel.org, kernel@xen0n.name, gregkh@linuxfoundation.org, rafael@kernel.org Subject: [PATCH v2] mm: add build-time option for hotplug memory default online type Date: Fri, 20 Dec 2024 13:31:02 -0500 Message-ID: <20241220183102.257410-1-gourry@gourry.net> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Memory hotplug presently auto-onlines memory into ZONE_NORMAL when CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=3Dy. The memhp_default_state boot param was added to allow runtime config. Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with CONFIG_MHP_DEFAULT_ONLINE_TYPE as a choice config. The choices sync up with the 'memhp_default_state' boot parameter. Selections: CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE =3D> mhp_default_online_type =3D "offline" Memory will not be onlined automatically. CONFIG_MHP_DEFAULT_ONLINE_TYPE_AUTO =3D> mhp_default_online_type =3D "online" Memory will be onlined automatically. The zone will be chosen by the kernel. CONFIG_MHP_DEFAULT_ONLINE_TYPE_KERNEL =3D> mhp_default_online_type =3D "online_kernel" Memory will be onlined automatically. The zone will be kernel capable (typically ZONE_NORMAL). CONFIG_MHP_DEFAULT_TYPE_MOVABLE =3D> mhp_default_online_type =3D "online_movable" Memory will be onlined automatically. The zone will be ZONE_MOVABLE. CONFIG_MHP_DEFAULT_ONLINE_TYPE defaults to "offline" to match the existing CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=3Dn behavior. Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=3Dy can use CONFIG_MHP_DEFAULT_ONLINE_TYPE_AUTO for the same behavior. Signed-off-by: Gregory Price --- .../admin-guide/kernel-parameters.txt | 2 +- .../admin-guide/mm/memory-hotplug.rst | 2 +- arch/loongarch/configs/loongson3_defconfig | 6 +- drivers/base/memory.c | 4 +- include/linux/memory_hotplug.h | 5 +- mm/Kconfig | 64 +++++++++++++++++-- mm/memory_hotplug.c | 29 +++++++-- 7 files changed, 91 insertions(+), 21 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentatio= n/admin-guide/kernel-parameters.txt index e73383450240..2169a4db6781 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3351,7 +3351,7 @@ [KNL] Set the initial state for the memory hotplug onlining policy. If not specified, the default value is set according to the - CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config + CONFIG_MHP_DEFAULT_ONLINE_TYPE kernel config option. See Documentation/admin-guide/mm/memory-hotplug.rst. =20 diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentatio= n/admin-guide/mm/memory-hotplug.rst index cb2c080f400c..aa5e703233e7 100644 --- a/Documentation/admin-guide/mm/memory-hotplug.rst +++ b/Documentation/admin-guide/mm/memory-hotplug.rst @@ -280,7 +280,7 @@ The following files are currently defined: blocks; configure auto-onlining. =20 The default value depends on the - CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel configuration + CONFIG_MHP_DEFAULT_ONLINE_TYPE kernel configuration option. =20 See the ``state`` property of memory blocks for details. diff --git a/arch/loongarch/configs/loongson3_defconfig b/arch/loongarch/co= nfigs/loongson3_defconfig index 4dffc90192f7..ffc3514b8a00 100644 --- a/arch/loongarch/configs/loongson3_defconfig +++ b/arch/loongarch/configs/loongson3_defconfig @@ -113,7 +113,11 @@ CONFIG_ZBUD=3Dy CONFIG_ZSMALLOC=3Dm # CONFIG_COMPAT_BRK is not set CONFIG_MEMORY_HOTPLUG=3Dy -CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=3Dy +# CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE is not set +CONFIG_MHP_DEFAULT_ONLINE_TYPE_AUTO=3Dy +# CONFIG_MHP_DEFAULT_ONLINE_TYPE_KERNEL is not set +# CONFIG_MHP_DEFAULT_ONLINE_TYPE_MOVABLE is not set +CONFIG_MHP_DEFAULT_ONLINE_TYPE=3D"online" CONFIG_MEMORY_HOTREMOVE=3Dy CONFIG_KSM=3Dy CONFIG_TRANSPARENT_HUGEPAGE=3Dy diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 67858eeb92ed..348c5dbbfa68 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -512,7 +512,7 @@ static ssize_t auto_online_blocks_show(struct device *d= ev, struct device_attribute *attr, char *buf) { return sysfs_emit(buf, "%s\n", - online_type_to_str[mhp_default_online_type]); + online_type_to_str[mhp_get_default_online_type()]); } =20 static ssize_t auto_online_blocks_store(struct device *dev, @@ -524,7 +524,7 @@ static ssize_t auto_online_blocks_store(struct device *= dev, if (online_type < 0) return -EINVAL; =20 - mhp_default_online_type =3D online_type; + mhp_set_default_online_type(online_type); return count; } =20 diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index b27ddce5d324..eaac5ae8c05c 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -144,8 +144,6 @@ extern u64 max_mem_size; =20 extern int mhp_online_type_from_str(const char *str); =20 -/* Default online_type (MMOP_*) when new memory blocks are added. */ -extern int mhp_default_online_type; /* If movable_node boot option specified */ extern bool movable_node_enabled; static inline bool movable_node_is_enabled(void) @@ -303,6 +301,9 @@ static inline void __remove_memory(u64 start, u64 size)= {} #endif /* CONFIG_MEMORY_HOTREMOVE */ =20 #ifdef CONFIG_MEMORY_HOTPLUG +/* Default online_type (MMOP_*) when new memory blocks are added. */ +extern int mhp_get_default_online_type(void); +extern void mhp_set_default_online_type(int online_type); extern void __ref free_area_init_core_hotplug(struct pglist_data *pgdat); extern int __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); extern int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags); diff --git a/mm/Kconfig b/mm/Kconfig index 7949ab121070..29107df78275 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -550,20 +550,70 @@ menuconfig MEMORY_HOTPLUG =20 if MEMORY_HOTPLUG =20 -config MEMORY_HOTPLUG_DEFAULT_ONLINE - bool "Online the newly added memory blocks by default" - depends on MEMORY_HOTPLUG +choice + prompt "Memory Hotplug Default Online Type" + default MHP_DEFAULT_ONLINE_TYPE_OFFLINE help + Default memory type for driver managed hotplug memory. + This option sets the default policy setting for memory hotplug onlining policy (/sys/devices/system/memory/auto_online_blocks) which determines what happens to newly added memory regions. Policy setting can always be changed at runtime. + + The default is 'offline'. + + Select offline to defer onlining to drivers and user policy. + Select auto to let the kernel choose what zones to utilize. + Select online_kernel to generally allow kernel usage of this memory. + Select online_movable to generally disallow kernel usage of this memory. + + Example kernel usage would be page structs and page tables. + See Documentation/admin-guide/mm/memory-hotplug.rst for more informatio= n. =20 - Say Y here if you want all hot-plugged memory blocks to appear in - 'online' state by default. - Say N here if you want the default policy to keep all hot-plugged - memory blocks in 'offline' state. +config MHP_DEFAULT_ONLINE_TYPE_OFFLINE + bool "offline" + help + Driver managed memory will not be onlined by default. + Choose this for systems with drivers and user policy that + handle onlining of hotplug memory policy. + +config MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO + bool "auto" + help + Select this if you want the kernel to automatically online + memory into the zone it thinks is reasonable. This memory + may be utilized for kernel data (e.g. page tables). + +config MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL + bool "kernel" + help + Select this if you want the kernel to automatically online + hotplug memory into a zone capable of being used for kernel + data (e.g. page tables). This typically means ZONE_NORMAL. + +config MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE + bool "movable" + help + Select this if you want the kernel to automatically online + hotplug memory into ZONE_MOVABLE. This memory will generally + not be utilized for kernel data (e.g. page tables). + + This should only be used when the admin knows sufficient + ZONE_NORMAL memory is available to describe hotplug memory, + otherwise hotplug memory may fail to online. For example, + sufficient kernel-capable memory (ZONE_NORMAL) must be + available to allocate page structs to describe ZONE_MOVABLE. + +endchoice + +config MHP_DEFAULT_ONLINE_TYPE + string + default "offline" if MHP_DEFAULT_ONLINE_TYPE_OFFLINE + default "online" if MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO + default "online_kernel" if MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL + default "online_movable" if MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE =20 config MEMORY_HOTREMOVE bool "Allow for memory hot remove" diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 3b6f93962481..11421accaff9 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -219,11 +219,26 @@ void put_online_mems(void) =20 bool movable_node_enabled =3D false; =20 -#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE -int mhp_default_online_type =3D MMOP_OFFLINE; -#else -int mhp_default_online_type =3D MMOP_ONLINE; -#endif +static int mhp_default_online_type =3D -1; +int mhp_get_default_online_type(void) +{ + int type; + + if (mhp_default_online_type >=3D 0) + return mhp_default_online_type; + + type =3D mhp_online_type_from_str(CONFIG_MHP_DEFAULT_ONLINE_TYPE); + if (type < 0) + type =3D MMOP_OFFLINE; + + mhp_default_online_type =3D type; + return mhp_default_online_type; +} + +void mhp_set_default_online_type(int online_type) +{ + mhp_default_online_type =3D online_type; +} =20 static int __init setup_memhp_default_state(char *str) { @@ -1328,7 +1343,7 @@ static int check_hotplug_memory_range(u64 start, u64 = size) =20 static int online_memory_block(struct memory_block *mem, void *arg) { - mem->online_type =3D mhp_default_online_type; + mem->online_type =3D mhp_get_default_online_type(); return device_online(&mem->dev); } =20 @@ -1575,7 +1590,7 @@ int add_memory_resource(int nid, struct resource *res= , mhp_t mhp_flags) merge_system_ram_resource(res); =20 /* online pages if requested */ - if (mhp_default_online_type !=3D MMOP_OFFLINE) + if (mhp_get_default_online_type() !=3D MMOP_OFFLINE) walk_memory_blocks(start, size, NULL, online_memory_block); =20 return ret; --=20 2.47.1