diff options
| author | Dave Hansen <haveblue@us.ibm.com> | 2005-10-29 18:16:53 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-10-29 21:40:44 -0700 |
| commit | bdc8cb984576ab5b550c8b24c6fa111a873503e3 (patch) | |
| tree | f94548988874caa10d770e6e65bc50c925abf825 /include/linux/mmzone.h | |
| parent | 208d54e5513c0c02d85af0990901354c74364d5c (diff) | |
[PATCH] memory hotplug locking: zone span seqlock
See the "fixup bad_range()" patch for more information, but this actually
creates a the lock to protect things making assumptions about a zone's size
staying constant at runtime.
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 | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index e050d68963a..f5fa3082fd6 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -12,6 +12,7 @@ #include <linux/threads.h> #include <linux/numa.h> #include <linux/init.h> +#include <linux/seqlock.h> #include <asm/atomic.h> /* Free memory management - zoned buddy allocator. */ @@ -137,6 +138,10 @@ struct zone { * free areas of different sizes */ spinlock_t lock; +#ifdef CONFIG_MEMORY_HOTPLUG + /* see spanned/present_pages for more description */ + seqlock_t span_seqlock; +#endif struct free_area free_area[MAX_ORDER]; @@ -220,6 +225,16 @@ struct zone { /* zone_start_pfn == zone_start_paddr >> PAGE_SHIFT */ unsigned long zone_start_pfn; + /* + * zone_start_pfn, spanned_pages and present_pages are all + * protected by span_seqlock. It is a seqlock because it has + * to be read outside of zone->lock, and it is done in the main + * allocator path. But, it is written quite infrequently. + * + * The lock is declared along with zone->lock because it is + * frequently read in proximity to zone->lock. It's good to + * give them a chance of being in the same cacheline. + */ unsigned long spanned_pages; /* total size, including holes */ unsigned long present_pages; /* amount of memory (excluding holes) */ |