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| author | Dave Hansen <haveblue@us.ibm.com> | 2005-10-29 18:16:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:44 -0700 |
| commit | 208d54e5513c0c02d85af0990901354c74364d5c (patch) | |
| tree | 83922f1d4a83f19bffcbff299044f421bd7e9c73 /include/linux/mmzone.h | |
| parent | c6a57e19e464db118dc4ab9cfe9e9748c6d630a0 (diff) | |
| download | lwn-208d54e5513c0c02d85af0990901354c74364d5c.tar.gz lwn-208d54e5513c0c02d85af0990901354c74364d5c.zip | |
[PATCH] memory hotplug locking: node_size_lock
pgdat->node_size_lock is basically only neeeded in one place in the normal
code: show_mem(), which is the arch-specific sysrq-m printing function.
Strictly speaking, the architectures not doing memory hotplug do no need this
locking in show_mem(). However, they are all included for completeness. This
should also make any future consolidation of all of the implementations a
little more straightforward.
This lock is also held in the sparsemem code during a memory removal, as
sections are invalidated. This is the place there pfn_valid() is made false
for a memory area that's being removed. The lock is only required when doing
pfn_valid() operations on memory which the user does not already have a
reference on the page, such as in show_mem().
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 4674145bb63d..e050d68963a1 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -273,6 +273,16 @@ typedef struct pglist_data { struct page *node_mem_map; #endif struct bootmem_data *bdata; +#ifdef CONFIG_MEMORY_HOTPLUG + /* + * Must be held any time you expect node_start_pfn, node_present_pages + * or node_spanned_pages stay constant. Holding this will also + * guarantee that any pfn_valid() stays that way. + * + * Nests above zone->lock and zone->size_seqlock. + */ + spinlock_t node_size_lock; +#endif unsigned long node_start_pfn; unsigned long node_present_pages; /* total number of physical pages */ unsigned long node_spanned_pages; /* total size of physical page @@ -293,6 +303,8 @@ typedef struct pglist_data { #endif #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) +#include <linux/memory_hotplug.h> + extern struct pglist_data *pgdat_list; void __get_zone_counts(unsigned long *active, unsigned long *inactive, |