The patch titled Subject: s390/mm: implement MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers has been added to the -mm mm-unstable branch. Its filename is s390-mm-implement-mem_prepare_online-mem_finish_offline-notifiers.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/s390-mm-implement-mem_prepare_online-mem_finish_offline-notifiers.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx> Subject: s390/mm: implement MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers Date: Tue, 28 Nov 2023 16:52:26 +0100 MEM_PREPARE_ONLINE memory notifier makes memory block physical accessible via sclp assign command. The notifier ensures self-contained memory maps are accessible and hence enabling the "memmap on memory" on s390. MEM_FINISH_OFFLINE memory notifier shifts the memory block to an inaccessible state via sclp unassign command. Implementation considerations: * When MHP_MEMMAP_ON_MEMORY is disabled, the system retains the old behavior. This means the memory map is allocated from default memory. * If MACHINE_HAS_EDAT1 is unavailable, MHP_MEMMAP_ON_MEMORY is automatically disabled. This ensures that vmemmap pagetables do not consume additional memory from the default memory allocator. * The MEM_GOING_ONLINE notifier has been modified to perform no operation, as MEM_PREPARE_ONLINE already executes the sclp assign command. * The MEM_CANCEL_ONLINE/MEM_OFFLINE notifier now performs no operation, as MEM_FINISH_OFFLINE already executes the sclp unassign command. Link: https://lkml.kernel.org/r/20231128155227.1315063-5-sumanthk@xxxxxxxxxxxxx Signed-off-by: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx> Reviewed-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Heiko Carstens <hca@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/s390/char/sclp_cmd.c | 41 ++++++++++++++++++++++++++++----- 1 file changed, 35 insertions(+), 6 deletions(-) --- a/drivers/s390/char/sclp_cmd.c~s390-mm-implement-mem_prepare_online-mem_finish_offline-notifiers +++ a/drivers/s390/char/sclp_cmd.c @@ -18,6 +18,7 @@ #include <linux/mm.h> #include <linux/mmzone.h> #include <linux/memory.h> +#include <linux/memory_hotplug.h> #include <linux/module.h> #include <asm/ctlreg.h> #include <asm/chpid.h> @@ -26,6 +27,7 @@ #include <asm/sclp.h> #include <asm/numa.h> #include <asm/facility.h> +#include <asm/page-states.h> #include "sclp.h" @@ -340,13 +342,38 @@ static int sclp_mem_notifier(struct noti if (contains_standby_increment(start, start + size)) rc = -EPERM; break; - case MEM_GOING_ONLINE: + case MEM_PREPARE_ONLINE: + /* + * Access the altmap_start_pfn and altmap_nr_pages fields + * within the struct memory_notify specifically when dealing + * with only MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers. + * + * When altmap is in use, take the specified memory range + * online, which includes the altmap. + */ + if (arg->altmap_nr_pages) { + start = PFN_PHYS(arg->altmap_start_pfn); + size += PFN_PHYS(arg->altmap_nr_pages); + } rc = sclp_mem_change_state(start, size, 1); + if (rc || !arg->altmap_nr_pages) + break; + /* + * Set CMMA state to nodat here, since the struct page memory + * at the beginning of the memory block will not go through the + * buddy allocator later. + */ + __arch_set_page_nodat((void *)__va(start), arg->altmap_nr_pages); break; - case MEM_CANCEL_ONLINE: - sclp_mem_change_state(start, size, 0); - break; - case MEM_OFFLINE: + case MEM_FINISH_OFFLINE: + /* + * When altmap is in use, take the specified memory range + * offline, which includes the altmap. + */ + if (arg->altmap_nr_pages) { + start = PFN_PHYS(arg->altmap_start_pfn); + size += PFN_PHYS(arg->altmap_nr_pages); + } sclp_mem_change_state(start, size, 0); break; default: @@ -397,7 +424,9 @@ static void __init add_memory_merged(u16 if (!size) goto skip_add; for (addr = start; addr < start + size; addr += block_size) - add_memory(0, addr, block_size, MHP_NONE); + add_memory(0, addr, block_size, + MACHINE_HAS_EDAT1 ? + MHP_MEMMAP_ON_MEMORY | MHP_OFFLINE_INACCESSIBLE : MHP_NONE); skip_add: first_rn = rn; num = 1; _ Patches currently in -mm which might be from sumanthk@xxxxxxxxxxxxx are mm-memory_hotplug-add-missing-mem_hotplug_lock.patch mm-memory_hotplug-fix-error-handling-in-add_memory_resource.patch mm-use-vmem_altmap-code-without-config_zone_device.patch mm-memory_hotplug-introduce-mem_prepare_online-mem_finish_offline-notifiers.patch s390-mm-allocate-vmemmap-pages-from-self-contained-memory-range.patch s390-sclp-remove-unhandled-memory-notifier-type.patch s390-mm-implement-mem_prepare_online-mem_finish_offline-notifiers.patch s390-enable-mhp_memmap_on_memory.patch