Re: [PATCH v20 0/7] Virtio-balloon Enhancement

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Wei Wang wrote:
> Thanks for the effort. That's actually caused by the previous "!node" 
> path, which incorrectly changed "index = (index | RADIX_TREE_MAP_MASK) + 
> 1". With the change below, it will run pretty well with the test cases.
> 
> if (!node && !bitmap)
>      return size;
> 
> Would you mind to have a try with the v20 RESEND patch that was just 
> shared?

No. Please explain what "!node" situation indicates. Why did you try
"index = (index | RADIX_TREE_MAP_MASK) + 1; continue;" in the previous patch?

+unsigned long xb_find_set(struct xb *xb, unsigned long size,
+			  unsigned long offset)
+{
+	struct radix_tree_root *root = &xb->xbrt;
+	struct radix_tree_node *node;
+	void __rcu **slot;
+	struct ida_bitmap *bitmap;
+	unsigned long index = offset / IDA_BITMAP_BITS;
+	unsigned long index_end = size / IDA_BITMAP_BITS;
+	unsigned long bit = offset % IDA_BITMAP_BITS;
+
+	if (unlikely(offset >= size))
+		return size;
+
+	while (index <= index_end) {
+		unsigned long ret;
+		unsigned int nbits = size - index * IDA_BITMAP_BITS;
+
+		bitmap = __radix_tree_lookup(root, index, &node, &slot);
+
+		if (!node && !bitmap)
+			return size;
+
+		if (bitmap) {
+			if (nbits > IDA_BITMAP_BITS)
+				nbits = IDA_BITMAP_BITS;
+
+			ret = find_next_bit(bitmap->bitmap, nbits, bit);
+			if (ret != nbits)
+				return ret + index * IDA_BITMAP_BITS;
+		}
+		bit = 0;
+		index++;
+	}
+
+	return size;
+}

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