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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 <pasha.tatashin@oracle.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Baoquan He <bhe@redhat.com> Cc: Bharata B Rao <bharata@linux.vnet.ibm.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Steven Sistare <steven.sistare@oracle.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
fc44f7f923
commit
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5 changed files with 28 additions and 38 deletions
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@ -407,6 +407,8 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid,
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if (!mem_blk)
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return -EFAULT;
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mem_blk->nid = nid;
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if (!node_online(nid))
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return 0;
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@ -33,6 +33,7 @@ struct memory_block {
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void *hw; /* optional pointer to fw/hw data */
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int (*phys_callback)(struct memory_block *);
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struct device dev;
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int nid; /* NID for this memory block */
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};
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int arch_get_memory_phys_device(unsigned long start_pfn);
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@ -250,7 +250,6 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
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struct vmem_altmap *altmap, bool want_memblock)
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{
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int ret;
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int i;
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if (pfn_valid(phys_start_pfn))
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return -EEXIST;
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@ -259,23 +258,6 @@ static int __meminit __add_section(int nid, unsigned long phys_start_pfn,
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if (ret < 0)
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return ret;
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/*
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* Make all the pages reserved so that nobody will stumble over half
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* initialized state.
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* FIXME: We also have to associate it with a node because page_to_nid
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* relies on having page with the proper node.
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*/
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for (i = 0; i < PAGES_PER_SECTION; i++) {
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unsigned long pfn = phys_start_pfn + i;
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struct page *page;
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if (!pfn_valid(pfn))
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continue;
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page = pfn_to_page(pfn);
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set_page_node(page, nid);
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SetPageReserved(page);
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}
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if (!want_memblock)
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return 0;
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@ -908,8 +890,15 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
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int nid;
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int ret;
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struct memory_notify arg;
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struct memory_block *mem;
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/*
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* We can't use pfn_to_nid() because nid might be stored in struct page
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* which is not yet initialized. Instead, we find nid from memory block.
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*/
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mem = find_memory_block(__pfn_to_section(pfn));
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nid = mem->nid;
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nid = pfn_to_nid(pfn);
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/* associate pfn range with the zone */
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zone = move_pfn_range(online_type, nid, pfn, nr_pages);
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@ -1143,10 +1143,9 @@ static void free_one_page(struct zone *zone,
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}
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static void __meminit __init_single_page(struct page *page, unsigned long pfn,
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unsigned long zone, int nid, bool zero)
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unsigned long zone, int nid)
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{
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if (zero)
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mm_zero_struct_page(page);
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mm_zero_struct_page(page);
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set_page_links(page, zone, nid, pfn);
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init_page_count(page);
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page_mapcount_reset(page);
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@ -1160,12 +1159,6 @@ static void __meminit __init_single_page(struct page *page, unsigned long pfn,
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#endif
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}
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static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
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int nid, bool zero)
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{
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return __init_single_page(pfn_to_page(pfn), pfn, zone, nid, zero);
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}
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#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
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static void __meminit init_reserved_page(unsigned long pfn)
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{
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@ -1184,7 +1177,7 @@ static void __meminit init_reserved_page(unsigned long pfn)
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if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
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break;
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}
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__init_single_pfn(pfn, zid, nid, true);
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__init_single_page(pfn_to_page(pfn), pfn, zid, nid);
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}
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#else
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static inline void init_reserved_page(unsigned long pfn)
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@ -1501,7 +1494,7 @@ static unsigned long __init deferred_init_pages(int nid, int zid,
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} else {
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page++;
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}
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__init_single_page(page, pfn, zid, nid, true);
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__init_single_page(page, pfn, zid, nid);
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nr_pages++;
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}
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return (nr_pages);
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@ -5434,6 +5427,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
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pg_data_t *pgdat = NODE_DATA(nid);
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unsigned long pfn;
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unsigned long nr_initialised = 0;
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struct page *page;
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#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
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struct memblock_region *r = NULL, *tmp;
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#endif
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@ -5486,6 +5480,11 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
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#endif
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not_early:
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page = pfn_to_page(pfn);
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__init_single_page(page, pfn, zone, nid);
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if (context == MEMMAP_HOTPLUG)
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SetPageReserved(page);
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/*
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* Mark the block movable so that blocks are reserved for
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* movable at startup. This will force kernel allocations
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@ -5502,15 +5501,8 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
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* because this is done early in sparse_add_one_section
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*/
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if (!(pfn & (pageblock_nr_pages - 1))) {
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struct page *page = pfn_to_page(pfn);
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__init_single_page(page, pfn, zone, nid,
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context != MEMMAP_HOTPLUG);
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set_pageblock_migratetype(page, MIGRATE_MOVABLE);
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cond_resched();
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} else {
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__init_single_pfn(pfn, zone, nid,
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context != MEMMAP_HOTPLUG);
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}
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}
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}
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@ -779,7 +779,13 @@ int __meminit sparse_add_one_section(struct pglist_data *pgdat,
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goto out;
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}
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memset(memmap, 0, sizeof(struct page) * PAGES_PER_SECTION);
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#ifdef CONFIG_DEBUG_VM
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/*
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* Poison uninitialized struct pages in order to catch invalid flags
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* combinations.
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*/
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memset(memmap, PAGE_POISON_PATTERN, sizeof(struct page) * PAGES_PER_SECTION);
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#endif
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section_mark_present(ms);
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