search for: bitmap_full

...he IDR_FREE tag set. We only clear the IDR_FREE tag once the > > bitmap is full. So if we try to find a free slot and the tag is clear, > > we know the bitmap is full. > > > > OK. But does using IDR_FREE tag have more benefit than cost? > You are doing > > if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS)) > radix_tree_iter_tag_clear(root, &iter, IDR_FREE); > > for each xb_set_bit() call. How likely do we hit ERR_PTR(-ENOSPC) path? > Isn't removing both bitmap_full() and ERR_PTR(-ENOSPC) better? You're assuming that the purpose of using...

...rtio_balloon_pbp_free(pbp); > + } > > - set_bit((rb_offset - rb_aligned_offset) / BALLOON_PAGE_SIZE, > - pbp->bitmap); > + if (!pbp->bitmap) { > + virtio_balloon_pbp_alloc(pbp, base_gpa, subpages); > + } > > - if (bitmap_full(pbp->bitmap, subpages)) { > - /* We've accumulated a full host page, we can actually discard > - * it now */ > + set_bit((rb_offset - rb_aligned_offset) / BALLOON_PAGE_SIZE, > + pbp->bitmap); > > - ram_block_discard_range(rb,...

This patch adds support to find next 1 or 0 bit in a xbmitmap range and clear a range of bits. More possible optimizations to add in the future: 1) xb_set_bit_range: set a range of bits. 2) when searching a bit, if the bit is not found in the slot, move on to the next slot directly. 3) add tags to help searching. Signed-off-by: Wei Wang <wei.w.wang at intel.com> Cc: Matthew Wilcox

This patch adds support to find next 1 or 0 bit in a xbmitmap range and clear a range of bits. More possible optimizations to add in the future: 1) xb_set_bit_range: set a range of bits. 2) when searching a bit, if the bit is not found in the slot, move on to the next slot directly. 3) add tags to help searching. Signed-off-by: Wei Wang <wei.w.wang at intel.com> Cc: Matthew Wilcox

...rn -ENOMEM; + } + bitmap = rcu_dereference_raw(*slot); + if (!bitmap) { + bitmap = this_cpu_xchg(ida_bitmap, NULL); + if (!bitmap) + return -ENOMEM; + memset(bitmap, 0, sizeof(*bitmap)); + radix_tree_iter_replace(root, &iter, slot, bitmap); + } + + __set_bit(bit, bitmap->bitmap); + if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS)) + radix_tree_iter_tag_clear(root, &iter, IDR_FREE); + return 0; +} +EXPORT_SYMBOL(xb_set_bit); + +/** + * xb_clear_bit() - Clear a bit in the XBitmap. + * @xb: The XBitmap. + * @bit: Index of the bit to clear. + * + * This function is used to clear a bit in...

...rn -ENOMEM; + } + bitmap = rcu_dereference_raw(*slot); + if (!bitmap) { + bitmap = this_cpu_xchg(ida_bitmap, NULL); + if (!bitmap) + return -ENOMEM; + memset(bitmap, 0, sizeof(*bitmap)); + radix_tree_iter_replace(root, &iter, slot, bitmap); + } + + __set_bit(bit, bitmap->bitmap); + if (bitmap_full(bitmap->bitmap, IDA_BITMAP_BITS)) + radix_tree_iter_tag_clear(root, &iter, IDR_FREE); + return 0; +} +EXPORT_SYMBOL(xb_set_bit); + +/** + * xb_clear_bit() - Clear a bit in the XBitmap. + * @xb: The XBitmap. + * @bit: Index of the bit to clear. + * + * This function is used to clear a bit in...

...r/include/linux/bitmap.h:205: error: `BITS_PER_LONG' undeclared (first use in this function) /usr/include/linux/bitmap.h: In function `bitmap_empty': /usr/include/linux/bitmap.h:213: error: `BITS_PER_LONG' undeclared (first use in this function) /usr/include/linux/bitmap.h: In function `bitmap_full': /usr/include/linux/bitmap.h:221: error: `BITS_PER_LONG' undeclared (first use in this function) /usr/include/linux/bitmap.h: In function `bitmap_shift_right': /usr/include/linux/bitmap.h:235: error: `BITS_PER_LONG' undeclared (first use in this function) /usr/include/linux/bitmap....

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live