[PATCH] memory hotplug locking: zone span seqlock (bdc8cb98) · Commits · 戴 / test

include/linux/memory_hotplug.h

+37 −2

Original line number	Diff line number	Diff line
		@@ -16,13 +16,36 @@ void pgdat_resize_lock(struct pglist_data pgdat, unsigned long flags)
		static inline
		void pgdat_resize_unlock(struct pglist_data pgdat, unsigned long flags)
		{
		spin_lock_irqrestore(&pgdat->node_size_lock, *flags);
		spin_unlock_irqrestore(&pgdat->node_size_lock, *flags);
		}
		static inline
		void pgdat_resize_init(struct pglist_data *pgdat)
		{
		spin_lock_init(&pgdat->node_size_lock);
		}
		/*
		* Zone resizing functions
		*/
		static inline unsigned zone_span_seqbegin(struct zone *zone)
		{
		return read_seqbegin(&zone->span_seqlock);
		}
		static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
		{
		return read_seqretry(&zone->span_seqlock, iv);
		}
		static inline void zone_span_writelock(struct zone *zone)
		{
		write_seqlock(&zone->span_seqlock);
		}
		static inline void zone_span_writeunlock(struct zone *zone)
		{
		write_sequnlock(&zone->span_seqlock);
		}
		static inline void zone_seqlock_init(struct zone *zone)
		{
		seqlock_init(&zone->span_seqlock);
		}
		#else /* ! CONFIG_MEMORY_HOTPLUG */
		/*
		* Stub functions for when hotplug is off
		@@ -30,5 +53,17 @@ void pgdat_resize_init(struct pglist_data *pgdat)
		static inline void pgdat_resize_lock(struct pglist_data p, unsigned long f) {}
		static inline void pgdat_resize_unlock(struct pglist_data p, unsigned long f) {}
		static inline void pgdat_resize_init(struct pglist_data *pgdat) {}
		#endif

		static inline unsigned zone_span_seqbegin(struct zone *zone)
		{
		return 0;
		}
		static inline int zone_span_seqretry(struct zone *zone, unsigned iv)
		{
		return 0;
		}
		static inline void zone_span_writelock(struct zone *zone) {}
		static inline void zone_span_writeunlock(struct zone *zone) {}
		static inline void zone_seqlock_init(struct zone *zone) {}
		#endif /* ! CONFIG_MEMORY_HOTPLUG */
		#endif /* __LINUX_MEMORY_HOTPLUG_H */

include/linux/mmzone.h

+15 −0

Original line number	Diff line number	Diff line
		@@ -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) */

mm/page_alloc.c

+14 −5

Original line number	Diff line number	Diff line
		@@ -33,6 +33,7 @@
		#include <linux/sysctl.h>
		#include <linux/cpu.h>
		#include <linux/cpuset.h>
		#include <linux/memory_hotplug.h>
		#include <linux/nodemask.h>
		#include <linux/vmalloc.h>

		@@ -80,12 +81,19 @@ unsigned long __initdata nr_all_pages;

		static int page_outside_zone_boundaries(struct zone zone, struct page page)
		{
		if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
		return 1;
		if (page_to_pfn(page) < zone->zone_start_pfn)
		return 1;
		int ret = 0;
		unsigned seq;
		unsigned long pfn = page_to_pfn(page);

		return 0;
		do {
		seq = zone_span_seqbegin(zone);
		if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
		ret = 1;
		else if (pfn < zone->zone_start_pfn)
		ret = 1;
		} while (zone_span_seqretry(zone, seq));

		return ret;
		}

		static int page_is_consistent(struct zone zone, struct page page)
		@@ -1980,6 +1988,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
		zone->name = zone_names[j];
		spin_lock_init(&zone->lock);
		spin_lock_init(&zone->lru_lock);
		zone_seqlock_init(zone);
		zone->zone_pgdat = pgdat;
		zone->free_pages = 0;

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