From: Michal Hocko <mhocko@xxxxxxxx> Subject: mm, memory_hotplug: get rid of is_zone_device_section Device memory hotplug hooks into regular memory hotplug only half way. It needs memory sections to track struct pages but there is no need/desire to associate those sections with memory blocks and export them to the userspace via sysfs because they cannot be onlined anyway. This is currently expressed by for_device argument to arch_add_memory which then makes sure to associate the given memory range with ZONE_DEVICE. register_new_memory then relies on is_zone_device_section to distinguish special memory hotplug from the regular one. While this works now, later patches in this series want to move __add_zone outside of arch_add_memory path so we have to come up with something else. Add want_memblock down the __add_pages path and use it to control whether the section->memblock association should be done. arch_add_memory then just trivially want memblock for everything but for_device hotplug. remove_memory_section doesn't need is_zone_device_section either. We can simply skip all the memblock specific cleanup if there is no memblock for the given section. This shouldn't introduce any functional change. Link: http://lkml.kernel.org/r/20170515085827.16474-5-mhocko@xxxxxxxxxx Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Balbir Singh <bsingharora@xxxxxxxxx> Cc: Daniel Kiper <daniel.kiper@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Igor Mammedov <imammedo@xxxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Cc: Joonsoo Kim <js1304@xxxxxxxxx> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Reza Arbab <arbab@xxxxxxxxxxxxxxxxxx> Cc: Tobias Regnery <tobias.regnery@xxxxxxxxx> Cc: Toshi Kani <toshi.kani@xxxxxxx> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- 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 | 23 +++++++++-------------- include/linux/memory_hotplug.h | 2 +- mm/memory_hotplug.c | 9 ++++++--- 9 files changed, 22 insertions(+), 24 deletions(-) diff -puN arch/ia64/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/ia64/mm/init.c --- a/arch/ia64/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/ia64/mm/init.c @@ -658,7 +658,7 @@ int arch_add_memory(int nid, u64 start, zone = pgdat->node_zones + zone_for_memory(nid, start, size, ZONE_NORMAL, for_device); - ret = __add_pages(nid, zone, start_pfn, nr_pages); + ret = __add_pages(nid, zone, start_pfn, nr_pages, !for_device); if (ret) printk("%s: Problem encountered in __add_pages() as ret=%d\n", diff -puN arch/powerpc/mm/mem.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/powerpc/mm/mem.c --- a/arch/powerpc/mm/mem.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/powerpc/mm/mem.c @@ -151,7 +151,7 @@ int arch_add_memory(int nid, u64 start, zone = pgdata->node_zones + zone_for_memory(nid, start, size, 0, for_device); - return __add_pages(nid, zone, start_pfn, nr_pages); + return __add_pages(nid, zone, start_pfn, nr_pages, !for_device); } #ifdef CONFIG_MEMORY_HOTREMOVE diff -puN arch/s390/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/s390/mm/init.c --- a/arch/s390/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/s390/mm/init.c @@ -195,7 +195,7 @@ int arch_add_memory(int nid, u64 start, continue; nr_pages = (start_pfn + size_pages > zone_end_pfn) ? zone_end_pfn - start_pfn : size_pages; - rc = __add_pages(nid, zone, start_pfn, nr_pages); + rc = __add_pages(nid, zone, start_pfn, nr_pages, !for_device); if (rc) break; start_pfn += nr_pages; diff -puN arch/sh/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/sh/mm/init.c --- a/arch/sh/mm/init.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/sh/mm/init.c @@ -498,7 +498,7 @@ int arch_add_memory(int nid, u64 start, ret = __add_pages(nid, pgdat->node_zones + zone_for_memory(nid, start, size, ZONE_NORMAL, for_device), - start_pfn, nr_pages); + start_pfn, nr_pages, !for_device); if (unlikely(ret)) printk("%s: Failed, __add_pages() == %d\n", __func__, ret); diff -puN arch/x86/mm/init_32.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/x86/mm/init_32.c --- a/arch/x86/mm/init_32.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/x86/mm/init_32.c @@ -831,7 +831,7 @@ int arch_add_memory(int nid, u64 start, unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; - return __add_pages(nid, zone, start_pfn, nr_pages); + return __add_pages(nid, zone, start_pfn, nr_pages, !for_device); } #ifdef CONFIG_MEMORY_HOTREMOVE diff -puN arch/x86/mm/init_64.c~mm-memory_hotplug-get-rid-of-is_zone_device_section arch/x86/mm/init_64.c --- a/arch/x86/mm/init_64.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/arch/x86/mm/init_64.c @@ -787,7 +787,7 @@ int arch_add_memory(int nid, u64 start, init_memory_mapping(start, start + size); - ret = __add_pages(nid, zone, start_pfn, nr_pages); + ret = __add_pages(nid, zone, start_pfn, nr_pages, !for_device); WARN_ON_ONCE(ret); /* update max_pfn, max_low_pfn and high_memory */ diff -puN drivers/base/memory.c~mm-memory_hotplug-get-rid-of-is_zone_device_section drivers/base/memory.c --- a/drivers/base/memory.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/drivers/base/memory.c @@ -685,14 +685,6 @@ static int add_memory_block(int base_sec return 0; } -static bool is_zone_device_section(struct mem_section *ms) -{ - struct page *page; - - page = sparse_decode_mem_map(ms->section_mem_map, __section_nr(ms)); - return is_zone_device_page(page); -} - /* * need an interface for the VM to add new memory regions, * but without onlining it. @@ -702,9 +694,6 @@ int register_new_memory(int nid, struct int ret = 0; struct memory_block *mem; - if (is_zone_device_section(section)) - return 0; - mutex_lock(&mem_sysfs_mutex); mem = find_memory_block(section); @@ -741,11 +730,16 @@ static int remove_memory_section(unsigne { struct memory_block *mem; - if (is_zone_device_section(section)) - return 0; - mutex_lock(&mem_sysfs_mutex); + + /* + * Some users of the memory hotplug do not want/need memblock to + * track all sections. Skip over those. + */ mem = find_memory_block(section); + if (!mem) + goto out_unlock; + unregister_mem_sect_under_nodes(mem, __section_nr(section)); mem->section_count--; @@ -754,6 +748,7 @@ static int remove_memory_section(unsigne else put_device(&mem->dev); +out_unlock: mutex_unlock(&mem_sysfs_mutex); return 0; } diff -puN include/linux/memory_hotplug.h~mm-memory_hotplug-get-rid-of-is_zone_device_section include/linux/memory_hotplug.h --- a/include/linux/memory_hotplug.h~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/include/linux/memory_hotplug.h @@ -111,7 +111,7 @@ extern int __remove_pages(struct zone *z /* reasonably generic interface to expand the physical pages in a zone */ extern int __add_pages(int nid, struct zone *zone, unsigned long start_pfn, - unsigned long nr_pages); + unsigned long nr_pages, bool want_memblock); #ifdef CONFIG_NUMA extern int memory_add_physaddr_to_nid(u64 start); diff -puN mm/memory_hotplug.c~mm-memory_hotplug-get-rid-of-is_zone_device_section mm/memory_hotplug.c --- a/mm/memory_hotplug.c~mm-memory_hotplug-get-rid-of-is_zone_device_section +++ a/mm/memory_hotplug.c @@ -494,7 +494,7 @@ static int __meminit __add_zone(struct z } static int __meminit __add_section(int nid, struct zone *zone, - unsigned long phys_start_pfn) + unsigned long phys_start_pfn, bool want_memblock) { int ret; @@ -511,6 +511,9 @@ static int __meminit __add_section(int n if (ret < 0) return ret; + if (!want_memblock) + return 0; + return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); } @@ -521,7 +524,7 @@ static int __meminit __add_section(int n * add the new pages. */ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn, - unsigned long nr_pages) + unsigned long nr_pages, bool want_memblock) { unsigned long i; int err = 0; @@ -549,7 +552,7 @@ int __ref __add_pages(int nid, struct zo } for (i = start_sec; i <= end_sec; i++) { - err = __add_section(nid, zone, section_nr_to_pfn(i)); + err = __add_section(nid, zone, section_nr_to_pfn(i), want_memblock); /* * EEXIST is finally dealt with by ioresource collision _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
