Re: [PATCH v2 3/8] mm/memory_hotplug: arch_remove_memory() and __remove_pages() with CONFIG_MEMORY_HOTPLUG

Dan Williams
2019-05-07T21:02:03Z

On Tue, May 7, 2019 at 11:38 AM David Hildenbrand <david@redhat.com> wrote:
>
> Let's prepare for better error handling while adding memory by allowing
> to use arch_remove_memory() and __remove_pages() even if
> CONFIG_MEMORY_HOTREMOVE is not set. CONFIG_MEMORY_HOTREMOVE effectively
> covers
> - Offlining of system ram (memory block devices) - offline_pages()
> - Unplug of system ram - remove_memory()
> - Unplug/remap of device memory - devm_memremap()
>
> This allows e.g. for handling like
>
> arch_add_memory()
> rc = do_something();
> if (rc) {
> arch_remove_memory();
> }
>
> Whereby do_something() will for example be memory block device creation
> after it has been factored out.

What's left after this? Can we just get rid of CONFIG_MEMORY_HOTREMOVE
option completely when CONFIG_MEMORY_HOTPLUG is enabled? It's not
clear to me why there was ever the option to compile out the remove
code when the add code is included.

> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> Cc: Rich Felker <dalias@libc.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: "Rafael J. Wysocki" <rafael@kernel.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Mike Rapoport <rppt@linux.ibm.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Oscar Salvador <osalvador@suse.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Mark Brown <broonie@kernel.org>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
> Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
> Cc: Andrew Banman <andrew.banman@hpe.com>
> Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Cc: Arun KS <arunks@codeaurora.org>
> Cc: Qian Cai <cai@lca.pw>
> Cc: Mathieu Malaterre <malat@debian.org>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> arch/ia64/mm/init.c | 2 --
> arch/powerpc/mm/mem.c | 2 --
> arch/s390/mm/init.c | 2 --
> arch/sh/mm/init.c | 2 --
> arch/x86/mm/init_32.c | 2 --
> arch/x86/mm/init_64.c | 2 --
> drivers/base/memory.c | 2 --
> include/linux/memory.h | 2 --
> include/linux/memory_hotplug.h | 2 --
> mm/memory_hotplug.c | 2 --
> mm/sparse.c | 6 ------
> 11 files changed, 26 deletions(-)
>
> diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
> index d28e29103bdb..aae75fd7b810 100644
> --- a/arch/ia64/mm/init.c
> +++ b/arch/ia64/mm/init.c
> @@ -681,7 +681,6 @@ int arch_add_memory(int nid, u64 start, u64 size,
> return ret;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> @@ -693,4 +692,3 @@ void arch_remove_memory(int nid, u64 start, u64 size,
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> }
> #endif
> -#endif
> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
> index a2b78e72452f..ddc69b59575c 100644
> --- a/arch/powerpc/mm/mem.c
> +++ b/arch/powerpc/mm/mem.c
> @@ -131,7 +131,6 @@ int __ref arch_add_memory(int nid, u64 start, u64 size,
> return __add_pages(nid, start_pfn, nr_pages, restrictions);
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> void __ref arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> @@ -164,7 +163,6 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
> resize_hpt_for_hotplug(memblock_phys_mem_size());
> }
> #endif
> -#endif /* CONFIG_MEMORY_HOTPLUG */
>
> #ifndef CONFIG_NEED_MULTIPLE_NODES
> void __init mem_topology_setup(void)
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index 1e0cbae69f12..eafa3c750efc 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -233,7 +233,6 @@ int arch_add_memory(int nid, u64 start, u64 size,
> return rc;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> @@ -245,5 +244,4 @@ void arch_remove_memory(int nid, u64 start, u64 size,
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> vmem_remove_mapping(start, size);
> }
> -#endif
> #endif /* CONFIG_MEMORY_HOTPLUG */
> diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
> index 5aeb4d7099a1..59c5fe511f25 100644
> --- a/arch/sh/mm/init.c
> +++ b/arch/sh/mm/init.c
> @@ -428,7 +428,6 @@ int memory_add_physaddr_to_nid(u64 addr)
> EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
> #endif
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> @@ -439,5 +438,4 @@ void arch_remove_memory(int nid, u64 start, u64 size,
> zone = page_zone(pfn_to_page(start_pfn));
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> }
> -#endif
> #endif /* CONFIG_MEMORY_HOTPLUG */
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index 075e568098f2..8d4bf2d97d50 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -859,7 +859,6 @@ int arch_add_memory(int nid, u64 start, u64 size,
> return __add_pages(nid, start_pfn, nr_pages, restrictions);
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> @@ -871,7 +870,6 @@ void arch_remove_memory(int nid, u64 start, u64 size,
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> }
> #endif
> -#endif
>
> int kernel_set_to_readonly __read_mostly;
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 20d14254b686..f1b55ddea23f 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1131,7 +1131,6 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,
> remove_pagetable(start, end, false, altmap);
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> static void __meminit
> kernel_physical_mapping_remove(unsigned long start, unsigned long end)
> {
> @@ -1156,7 +1155,6 @@ void __ref arch_remove_memory(int nid, u64 start, u64 size,
> __remove_pages(zone, start_pfn, nr_pages, altmap);
> kernel_physical_mapping_remove(start, start + size);
> }
> -#endif
> #endif /* CONFIG_MEMORY_HOTPLUG */
>
> static struct kcore_list kcore_vsyscall;
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index f180427e48f4..6e0cb4fda179 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -728,7 +728,6 @@ int hotplug_memory_register(int nid, struct mem_section *section)
> return ret;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> static void
> unregister_memory(struct memory_block *memory)
> {
> @@ -767,7 +766,6 @@ void unregister_memory_section(struct mem_section *section)
> out_unlock:
> mutex_unlock(&mem_sysfs_mutex);
> }
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
>
> /* return true if the memory block is offlined, otherwise, return false */
> bool is_memblock_offlined(struct memory_block *mem)
> diff --git a/include/linux/memory.h b/include/linux/memory.h
> index e1dc1bb2b787..474c7c60c8f2 100644
> --- a/include/linux/memory.h
> +++ b/include/linux/memory.h
> @@ -112,9 +112,7 @@ extern void unregister_memory_notifier(struct notifier_block *nb);
> extern int register_memory_isolate_notifier(struct notifier_block *nb);
> extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
> int hotplug_memory_register(int nid, struct mem_section *section);
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> extern void unregister_memory_section(struct mem_section *);
> -#endif
> extern int memory_dev_init(void);
> extern int memory_notify(unsigned long val, void *v);
> extern int memory_isolate_notify(unsigned long val, void *v);
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index ae892eef8b82..2d4de313926d 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -123,12 +123,10 @@ static inline bool movable_node_is_enabled(void)
> return movable_node_enabled;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> extern void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap);
> extern void __remove_pages(struct zone *zone, unsigned long start_pfn,
> unsigned long nr_pages, struct vmem_altmap *altmap);
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
>
> /*
> * Do we want sysfs memblock files created. This will allow userspace to online
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 202febe88b58..7b5439839d67 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -317,7 +317,6 @@ int __ref __add_pages(int nid, unsigned long phys_start_pfn,
> return err;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
> static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
> unsigned long start_pfn,
> @@ -581,7 +580,6 @@ void __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
>
> set_zone_contiguous(zone);
> }
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
>
> int set_online_page_callback(online_page_callback_t callback)
> {
> diff --git a/mm/sparse.c b/mm/sparse.c
> index fd13166949b5..d1d5e05f5b8d 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -604,7 +604,6 @@ static void __kfree_section_memmap(struct page *memmap,
>
> vmemmap_free(start, end, altmap);
> }
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> static void free_map_bootmem(struct page *memmap)
> {
> unsigned long start = (unsigned long)memmap;
> @@ -612,7 +611,6 @@ static void free_map_bootmem(struct page *memmap)
>
> vmemmap_free(start, end, NULL);
> }
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
> #else
> static struct page *__kmalloc_section_memmap(void)
> {
> @@ -651,7 +649,6 @@ static void __kfree_section_memmap(struct page *memmap,
> get_order(sizeof(struct page) * PAGES_PER_SECTION));
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> static void free_map_bootmem(struct page *memmap)
> {
> unsigned long maps_section_nr, removing_section_nr, i;
> @@ -681,7 +678,6 @@ static void free_map_bootmem(struct page *memmap)
> put_page_bootmem(page);
> }
> }
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
> #endif /* CONFIG_SPARSEMEM_VMEMMAP */
>
> /**
> @@ -746,7 +742,6 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
> return ret;
> }
>
> -#ifdef CONFIG_MEMORY_HOTREMOVE
> #ifdef CONFIG_MEMORY_FAILURE
> static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
> {
> @@ -823,5 +818,4 @@ void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
> PAGES_PER_SECTION - map_offset);
> free_section_usemap(memmap, usemap, altmap);
> }
> -#endif /* CONFIG_MEMORY_HOTREMOVE */
> #endif /* CONFIG_MEMORY_HOTPLUG */
> --
> 2.20.1
>