From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34661) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ewYuU-0008Cb-W6 for qemu-devel@nongnu.org; Thu, 15 Mar 2018 15:51:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ewYuU-0007nL-6d for qemu-devel@nongnu.org; Thu, 15 Mar 2018 15:51:35 -0400 References: <20180228180507.3964-1-mreitz@redhat.com> <20180228180507.3964-13-mreitz@redhat.com> From: John Snow Message-ID: <73d69c62-fdef-2c8f-8a55-ef6a2b9c9ebd@redhat.com> Date: Thu, 15 Mar 2018 15:51:13 -0400 MIME-Version: 1.0 In-Reply-To: <20180228180507.3964-13-mreitz@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 12/16] block/dirty-bitmap: Add bdrv_dirty_iter_next_area List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-block@nongnu.org Cc: Kevin Wolf , Fam Zheng , qemu-devel@nongnu.org, Stefan Hajnoczi On 02/28/2018 01:05 PM, Max Reitz wrote: > This new function allows to look for a consecutively dirty area in a > dirty bitmap. > > Signed-off-by: Max Reitz > --- > include/block/dirty-bitmap.h | 2 ++ > block/dirty-bitmap.c | 55 ++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 57 insertions(+) > > diff --git a/include/block/dirty-bitmap.h b/include/block/dirty-bitmap.h > index e3f4bbf51d..8c8f63e722 100644 > --- a/include/block/dirty-bitmap.h > +++ b/include/block/dirty-bitmap.h > @@ -79,6 +79,8 @@ void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, > void bdrv_reset_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, > int64_t offset, int64_t bytes); > int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter); > +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, > + uint64_t *offset, int *bytes); > void bdrv_set_dirty_iter(BdrvDirtyBitmapIter *hbi, int64_t offset); > int64_t bdrv_get_dirty_count(BdrvDirtyBitmap *bitmap); > int64_t bdrv_get_meta_dirty_count(BdrvDirtyBitmap *bitmap); > diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c > index d8e999226e..5d6b8dba89 100644 > --- a/block/dirty-bitmap.c > +++ b/block/dirty-bitmap.c > @@ -496,6 +496,61 @@ int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter) > return hbitmap_iter_next(&iter->hbi, true); > } > > +/** > + * Return the next consecutively dirty area in the dirty bitmap > + * belonging to the given iterator @iter. > + * > + * @max_offset: Maximum value that may be returned for > + * *offset + *bytes > + * @offset: Will contain the start offset of the next dirty area > + * @bytes: Will contain the length of the next dirty area > + * > + * Returns: True if a dirty area could be found before max_offset > + * (which means that *offset and *bytes then contain valid > + * values), false otherwise. > + * > + * Note that @iter is never advanced if false is returned. If an area > + * is found (which means that true is returned), it will be advanced > + * past that area. > + */ > +bool bdrv_dirty_iter_next_area(BdrvDirtyBitmapIter *iter, uint64_t max_offset, > + uint64_t *offset, int *bytes) > +{ > + uint32_t granularity = bdrv_dirty_bitmap_granularity(iter->bitmap); > + uint64_t gran_max_offset; > + int64_t ret; > + int size; > + > + if (max_offset == iter->bitmap->size) { > + /* If max_offset points to the image end, round it up by the > + * bitmap granularity */ > + gran_max_offset = ROUND_UP(max_offset, granularity); > + } else { > + gran_max_offset = max_offset; > + } > + > + ret = hbitmap_iter_next(&iter->hbi, false); > + if (ret < 0 || ret + granularity > gran_max_offset) { > + return false; > + } > + > + *offset = ret; > + size = 0; > + > + assert(granularity <= INT_MAX); > + > + do { > + /* Advance iterator */ > + ret = hbitmap_iter_next(&iter->hbi, true); > + size += granularity; > + } while (ret + granularity <= gran_max_offset && > + hbitmap_iter_next(&iter->hbi, false) == ret + granularity && > + size <= INT_MAX - granularity); > + > + *bytes = MIN(size, max_offset - *offset); > + return true; > +} > + > /* Called within bdrv_dirty_bitmap_lock..unlock */ > void bdrv_set_dirty_bitmap_locked(BdrvDirtyBitmap *bitmap, > int64_t offset, int64_t bytes) > 10, 11, 12: Reviewed-by: John Snow