From fc44f7f9231a73821fc858f5bc48883a9e78f6de Mon Sep 17 00:00:00 2001 From: Pavel Tatashin Date: Thu, 5 Apr 2018 16:22:56 -0700 Subject: mm/memory_hotplug: don't read nid from struct page during hotplug During memory hotplugging the probe routine will leave struct pages uninitialized, the same as it is currently done during boot. Therefore, we do not want to access the inside of struct pages before __init_single_page() is called during onlining. Because during hotplug we know that pages in one memory block belong to the same numa node, we can skip the checking. We should keep checking for the boot case. [pasha.tatashin@oracle.com: s/register_new_memory()/hotplug_memory_register()] Link: http://lkml.kernel.org/r/20180228030308.1116-6-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-6-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin Acked-by: Michal Hocko Reviewed-by: Ingo Molnar Cc: Baoquan He Cc: Bharata B Rao Cc: Daniel Jordan Cc: Dan Williams Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Kirill A. Shutemov Cc: Mel Gorman Cc: Steven Sistare Cc: Thomas Gleixner Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memory.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index f71e732c77b2..9f8cd856ca1e 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -109,7 +109,7 @@ extern int register_memory_notifier(struct notifier_block *nb); 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); -extern int register_new_memory(int, struct mem_section *); +int hotplug_memory_register(int nid, struct mem_section *section); #ifdef CONFIG_MEMORY_HOTREMOVE extern int unregister_memory_section(struct mem_section *); #endif -- cgit v1.2.3 From d0dc12e86b3197a14a908d4fe7cb35b73dda82b5 Mon Sep 17 00:00:00 2001 From: Pavel Tatashin Date: Thu, 5 Apr 2018 16:23:00 -0700 Subject: mm/memory_hotplug: optimize memory hotplug During memory hotplugging we traverse struct pages three times: 1. memset(0) in sparse_add_one_section() 2. loop in __add_section() to set do: set_page_node(page, nid); and SetPageReserved(page); 3. loop in memmap_init_zone() to call __init_single_pfn() This patch removes the first two loops, and leaves only loop 3. All struct pages are initialized in one place, the same as it is done during boot. The benefits: - We improve memory hotplug performance because we are not evicting the cache several times and also reduce loop branching overhead. - Remove condition from hotpath in __init_single_pfn(), that was added in order to fix the problem that was reported by Bharata in the above email thread, thus also improve performance during normal boot. - Make memory hotplug more similar to the boot memory initialization path because we zero and initialize struct pages only in one function. - Simplifies memory hotplug struct page initialization code, and thus enables future improvements, such as multi-threading the initialization of struct pages in order to improve hotplug performance even further on larger machines. [pasha.tatashin@oracle.com: v5] Link: http://lkml.kernel.org/r/20180228030308.1116-7-pasha.tatashin@oracle.com Link: http://lkml.kernel.org/r/20180215165920.8570-7-pasha.tatashin@oracle.com Signed-off-by: Pavel Tatashin Reviewed-by: Ingo Molnar Cc: Michal Hocko Cc: Baoquan He Cc: Bharata B Rao Cc: Daniel Jordan Cc: Dan Williams Cc: Greg Kroah-Hartman Cc: "H. Peter Anvin" Cc: Kirill A. Shutemov Cc: Mel Gorman Cc: Steven Sistare Cc: Thomas Gleixner Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memory.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/memory.h') diff --git a/include/linux/memory.h b/include/linux/memory.h index 9f8cd856ca1e..31ca3e28b0eb 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -33,6 +33,7 @@ struct memory_block { void *hw; /* optional pointer to fw/hw data */ int (*phys_callback)(struct memory_block *); struct device dev; + int nid; /* NID for this memory block */ }; int arch_get_memory_phys_device(unsigned long start_pfn); -- cgit v1.2.3