Messages in this thread Patch in this message | | | Date | Tue, 14 Feb 2006 22:24:34 +0900 | From | Yasunori Goto <> | Subject | Re: [Lhms-devel] [RFC/PATCH: 002/010] Memory hotplug for new nodes with pgdat allocation. (Wait table and zonelists initalization) |
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> Yasunori Goto wrote: > > > >> On Fri, 2006-02-10 at 23:20 +0900, Yasunori Goto wrote: > >>> static __meminit > >>> void zone_wait_table_init(struct zone *zone, unsigned long > >>> zone_size_pages) > >>> { > >>> - int i; > >>> + int i, hotadd = (system_state == SYSTEM_RUNNING); > >>> struct pglist_data *pgdat = zone->zone_pgdat; > >>> + unsigned long allocsize; > >>> > >>> /* > >>> * The per-page waitqueue mechanism uses hashed waitqueues > >>> * per zone. > >>> */ > >>> + if (hotadd && (zone_size_pages == PAGES_PER_SECTION)) > >>> + zone_size_pages = PAGES_PER_SECTION << 2; > >> I don't think I understand this calculation. You online only 4 sections > >> worth of pages? > > > > Ummmmm. > > I realized that I've forgotten many things about this patch > > due to long time keeping in storage. > > At least here looks strange indeed. > > I need shake my brain to recall it. :-( > > Ah, I'm not sure but it was because I didn't have a patch for zone's waittable resizing, > and resizing it looked impossible. Above code was just a quick hack for the case a zone > is initialized with only 1 section. > How large it should be ? or Resizing it, is necessary to be discussed.
Ok. How is like this patch? I changed wait_table_size() for it. If there is no objection, I'll continue....
Thanks.
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This patch is to initialize wait table and zonelists for new pgdat. When new node is added, free_area_init_node() is called to initialize pgdat. But, wait table must be allocated by kmalloc (not bootmem) for it. And, zonelists is accessed from any other process every time, So, stop_machine_run() is used for safety update.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Hiroyuki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Index: pgdat2/mm/page_alloc.c =================================================================== --- pgdat2.orig/mm/page_alloc.c 2006-02-14 18:50:37.000000000 +0900 +++ pgdat2/mm/page_alloc.c 2006-02-14 22:11:53.000000000 +0900 @@ -37,6 +37,7 @@ #include <linux/nodemask.h> #include <linux/vmalloc.h> #include <linux/mempolicy.h> +#include <linux/stop_machine.h> #include <asm/tlbflush.h> #include "internal.h" @@ -1789,6 +1790,24 @@ static inline unsigned long wait_table_s pages /= PAGES_PER_WAITQUEUE; + /* + * In memory hotplug case, the number of pages is just + * for the first section. But, there is no information how + * much memory will be added in the future, + * and this hash table cann't be reallocated. + * When memory hotplug is required, much memory will be + * necessary. Probably, bigger size is better. + * But kmalloc might fail if size is over order 3. + * This is to take wait_table size as much as possible. + */ + if (system_state == SYSTEM_RUNNING){ + unsigned long queue_head_size = 1; + while (queue_head_size < sizeof(wait_queue_head_t)) + queue_head_size <<= 1; + + pages = (1 << (PAGE_SHIFT + 3)) / queue_head_size; + } + while (size < pages) size <<= 1; @@ -2071,8 +2090,9 @@ void __init setup_per_cpu_pageset(void) static __meminit void zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages) { - int i; + int i, hotadd = (system_state == SYSTEM_RUNNING); struct pglist_data *pgdat = zone->zone_pgdat; + unsigned long allocsize; /* * The per-page waitqueue mechanism uses hashed waitqueues @@ -2080,9 +2100,12 @@ void zone_wait_table_init(struct zone *z */ zone->wait_table_size = wait_table_size(zone_size_pages); zone->wait_table_bits = wait_table_bits(zone->wait_table_size); - zone->wait_table = (wait_queue_head_t *) - alloc_bootmem_node(pgdat, zone->wait_table_size - * sizeof(wait_queue_head_t)); + allocsize = zone->wait_table_size * sizeof(wait_queue_head_t); + if (hotadd) + zone->wait_table = kmalloc(allocsize, GFP_KERNEL); + else + zone->wait_table = (wait_queue_head_t *) + alloc_bootmem_node(pgdat, allocsize); for(i = 0; i < zone->wait_table_size; ++i) init_waitqueue_head(zone->wait_table + i); @@ -2120,6 +2143,7 @@ static __meminit void init_currently_emp memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn); zone_init_free_lists(pgdat, zone, zone->spanned_pages); + zone->spanned_pages = size; } /* @@ -2818,3 +2842,53 @@ void *__init alloc_large_system_hash(con return table; } + +static inline int zone_previously_initialized(struct zone *zone) +{ + if (zone->wait_table_size) + return 1; + + return 0; +} + +#ifdef CONFIG_MEMORY_HOTPLUG +static int __build_all_zonelists(void *dummy) +{ + int i; + for_each_online_node(i) + build_zonelists(NODE_DATA(i)); + /* XXX: Cpuset must be updated when node is hotplugged. */ + return 0; +} + +DEFINE_SPINLOCK(zone_init_lock); +int hot_add_zone_init(struct zone *zone, unsigned long phys_start_pfn, + unsigned long size_pages) +{ + int ret = 0; + unsigned long flags; + spin_lock_irqsave(&zone_init_lock,flags); + if (zone_previously_initialized(zone)) { + ret = -EEXIST; + goto out; + } + + printk(KERN_DEBUG "hot add zone init %lx %lx.....\n", + phys_start_pfn, size_pages); + init_currently_empty_zone(zone, phys_start_pfn, size_pages); + zone_pcp_init(zone); + + /* + * This is an awfully blunt way to do this. But, the + * zonelists are accessed many times over large areas + * of performance-critical code in the allocator. + * That makes it very hard to get a conventional lock + * to work. This of this as a rw lock with a huge + * write cost. + */ + stop_machine_run(__build_all_zonelists, zone->zone_pgdat, NR_CPUS); +out: + spin_unlock_irqrestore(&zone_init_lock, flags); + return ret; +} +#endif Index: pgdat2/include/linux/mmzone.h =================================================================== --- pgdat2.orig/include/linux/mmzone.h 2006-02-14 18:14:59.000000000 +0900 +++ pgdat2/include/linux/mmzone.h 2006-02-14 18:50:44.000000000 +0900 @@ -403,7 +403,9 @@ static inline struct zone *next_zone(str static inline int populated_zone(struct zone *zone) { - return (!!zone->present_pages); + /* When hot-add, present page is 0 at this point. + So check spanned_pages instead of present_pages */ + return (!!zone->spanned_pages); } static inline int is_highmem_idx(int idx) Index: pgdat2/mm/memory_hotplug.c =================================================================== --- pgdat2.orig/mm/memory_hotplug.c 2006-02-14 18:50:12.000000000 +0900 +++ pgdat2/mm/memory_hotplug.c 2006-02-14 22:10:12.000000000 +0900 @@ -48,6 +48,8 @@ static int __add_section(struct zone *zo ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); + hot_add_zone_init(zone, phys_start_pfn, PAGES_PER_SECTION); + if (ret < 0) return ret; -- Yasunori Goto
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