shmem: Convert shmem_alloc_hugepage to XArray (7b8d046f) · Commits · 戴 / test

include/linux/radix-tree.h

+1 −5

Original line number	Diff line number	Diff line
		@@ -147,12 +147,11 @@ static inline unsigned int iter_shift(const struct radix_tree_iter *iter)
		* radix_tree_lookup_slot
		* radix_tree_tag_get
		* radix_tree_gang_lookup
		* radix_tree_gang_lookup_slot
		* radix_tree_gang_lookup_tag
		* radix_tree_gang_lookup_tag_slot
		* radix_tree_tagged
		*
		* The first 8 functions are able to be called locklessly, using RCU. The
		* The first 7 functions are able to be called locklessly, using RCU. The
		* caller must ensure calls to these functions are made within rcu_read_lock()
		* regions. Other readers (lock-free or otherwise) and modifications may be
		* running concurrently.
		@@ -263,9 +262,6 @@ void radix_tree_clear_tags(struct radix_tree_root , struct radix_tree_node ,
		unsigned int radix_tree_gang_lookup(const struct radix_tree_root *,
		void **results, unsigned long first_index,
		unsigned int max_items);
		unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *,
		void __rcu **results, unsigned long indices,
		unsigned long first_index, unsigned int max_items);
		int radix_tree_preload(gfp_t gfp_mask);
		int radix_tree_maybe_preload(gfp_t gfp_mask);
		int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order);

lib/radix-tree.c

+1 −43

Original line number	Diff line number	Diff line
		@@ -1097,7 +1097,7 @@ void __radix_tree_replace(struct radix_tree_root *root,
		* @slot: pointer to slot
		* @item: new item to store in the slot.
		*
		* For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(),
		* For use with radix_tree_lookup_slot() and
		* radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked
		* across slot lookup and replacement.
		*
		@@ -1731,48 +1731,6 @@ radix_tree_gang_lookup(const struct radix_tree_root root, void *results,
		}
		EXPORT_SYMBOL(radix_tree_gang_lookup);

		/**
		* radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
		* @root: radix tree root
		* @results: where the results of the lookup are placed
		* @indices: where their indices should be placed (but usually NULL)
		* @first_index: start the lookup from this key
		* @max_items: place up to this many items at *results
		*
		* Performs an index-ascending scan of the tree for present items. Places
		* their slots at *@results and returns the number of items which were
		* placed at *@results.
		*
		* The implementation is naive.
		*
		* Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
		* be dereferenced with radix_tree_deref_slot, and if using only RCU
		* protection, radix_tree_deref_slot may fail requiring a retry.
		*/
		unsigned int
		radix_tree_gang_lookup_slot(const struct radix_tree_root *root,
		void __rcu **results, unsigned long indices,
		unsigned long first_index, unsigned int max_items)
		{
		struct radix_tree_iter iter;
		void __rcu **slot;
		unsigned int ret = 0;

		if (unlikely(!max_items))
		return 0;

		radix_tree_for_each_slot(slot, root, &iter, first_index) {
		results[ret] = slot;
		if (indices)
		indices[ret] = iter.index;
		if (++ret == max_items)
		break;
		}

		return ret;
		}
		EXPORT_SYMBOL(radix_tree_gang_lookup_slot);

		/**
		* radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
		* based on a tag

mm/shmem.c

+4 −10

Original line number	Diff line number	Diff line
		@@ -1431,23 +1431,17 @@ static struct page *shmem_alloc_hugepage(gfp_t gfp,
		struct shmem_inode_info *info, pgoff_t index)
		{
		struct vm_area_struct pvma;
		struct inode *inode = &info->vfs_inode;
		struct address_space *mapping = inode->i_mapping;
		pgoff_t idx, hindex;
		void __rcu **results;
		struct address_space *mapping = info->vfs_inode.i_mapping;
		pgoff_t hindex;
		struct page *page;

		if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE))
		return NULL;

		hindex = round_down(index, HPAGE_PMD_NR);
		rcu_read_lock();
		if (radix_tree_gang_lookup_slot(&mapping->i_pages, &results, &idx,
		hindex, 1) && idx < hindex + HPAGE_PMD_NR) {
		rcu_read_unlock();
		if (xa_find(&mapping->i_pages, &hindex, hindex + HPAGE_PMD_NR - 1,
		XA_PRESENT))
		return NULL;
		}
		rcu_read_unlock();

		shmem_pseudo_vma_init(&pvma, info, hindex);
		page = alloc_pages_vma(gfp \| __GFP_COMP \| __GFP_NORETRY \| __GFP_NOWARN,

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