[Qemu-devel] [PATCH 07/11] block: optimization blk_pwrite_compressed()

["Denis V. Lunev" <den@openvz.org>]

From: Pavel Butsykin <pbutsykin@virtuozzo.com>

For bdrv_pwrite_compressed() it looks like most of the code creating coroutine
is duplicated in blk_prw(). So we can just add a flag(BDRV_REQ_WRITE_COMPRESSED)
and use the blk_prw() as a generic one.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Jeff Cody <jcody@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Eric Blake <eblake@redhat.com>
CC: John Snow <jsnow@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
---
 block/block-backend.c          | 19 +++++++++++------
 block/io.c                     | 48 ------------------------------------------
 include/block/block.h          |  3 +--
 include/sysemu/block-backend.h |  3 +++
 4 files changed, 17 insertions(+), 56 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 3c1fc50..9e1c793 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -785,7 +785,11 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
         flags |= BDRV_REQ_FUA;
     }
 
-    return bdrv_co_pwritev(blk_bs(blk), offset, bytes, qiov, flags);
+    if (flags & BDRV_REQ_WRITE_COMPRESSED) {
+        return bdrv_co_pwritev_compressed(blk_bs(blk), offset, bytes, qiov);
+    } else {
+        return bdrv_co_pwritev(blk_bs(blk), offset, bytes, qiov, flags);
+    }
 }
 
 typedef struct BlkRwCo {
@@ -1480,12 +1484,15 @@ int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
                           int count)
 {
-    int ret = blk_check_byte_request(blk, offset, count);
-    if (ret < 0) {
-        return ret;
-    }
+    return blk_prw(blk, offset, (void *) buf, count, blk_write_entry,
+                   BDRV_REQ_WRITE_COMPRESSED);
+}
 
-    return bdrv_pwrite_compressed(blk_bs(blk), offset, buf, count);
+int coroutine_fn blk_co_pwritev_compressed(BlockBackend *blk, int64_t offset,
+                                           unsigned int bytes,
+                                           QEMUIOVector *qiov)
+{
+    return blk_co_pwritev(blk, offset, bytes, qiov, BDRV_REQ_WRITE_COMPRESSED);
 }
 
 int blk_truncate(BlockBackend *blk, int64_t offset)
diff --git a/block/io.c b/block/io.c
index 4b06de8..29f5962 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1805,54 +1805,6 @@ int coroutine_fn bdrv_co_pwritev_compressed(BlockDriverState *bs,
                                          bytes >> BDRV_SECTOR_BITS, qiov);
 }
 
-typedef struct BdrvWriteCompressedCo {
-    BlockDriverState *bs;
-    int64_t offset;
-    QEMUIOVector *qiov;
-    int ret;
-} BdrvWriteCompressedCo;
-
-static void bdrv_write_compressed_co_entry(void *opaque)
-{
-    BdrvWriteCompressedCo *co = opaque;
-
-    co->ret = bdrv_co_pwritev_compressed(co->bs, co->offset, co->qiov->size,
-                                         co->qiov);
-}
-
-int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset,
-                           const void *buf, int count)
-{
-    BdrvWriteCompressedCo data;
-    QEMUIOVector qiov;
-    struct iovec iov = {
-        .iov_base = (void *)buf,
-        .iov_len = count,
-    };
-    qemu_iovec_init_external(&qiov, &iov, 1);
-
-    data = (BdrvWriteCompressedCo) {
-        .bs     = bs,
-        .offset = offset,
-        .qiov   = &qiov,
-        .ret    = -EINPROGRESS,
-    };
-
-    if (qemu_in_coroutine()) {
-        /* Fast-path if already in coroutine context */
-        bdrv_write_compressed_co_entry(&data);
-    } else {
-        AioContext *aio_context = bdrv_get_aio_context(bs);
-
-        Coroutine *co = qemu_coroutine_create(bdrv_write_compressed_co_entry);
-        qemu_coroutine_enter(co, &data);
-        while (data.ret == -EINPROGRESS) {
-            aio_poll(aio_context, true);
-        }
-    }
-    return data.ret;
-}
-
 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                       int64_t pos, int size)
 {
diff --git a/include/block/block.h b/include/block/block.h
index b687c0d..56fcab6 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -65,6 +65,7 @@ typedef enum {
     BDRV_REQ_MAY_UNMAP          = 0x4,
     BDRV_REQ_NO_SERIALISING     = 0x8,
     BDRV_REQ_FUA                = 0x10,
+    BDRV_REQ_WRITE_COMPRESSED   = 0x20,
 } BdrvRequestFlags;
 
 typedef struct BlockSizes {
@@ -421,8 +422,6 @@ const char *bdrv_get_node_name(const BlockDriverState *bs);
 const char *bdrv_get_device_name(const BlockDriverState *bs);
 const char *bdrv_get_device_or_node_name(const BlockDriverState *bs);
 int bdrv_get_flags(BlockDriverState *bs);
-int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset,
-                           const void *buf, int count);
 int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi);
 ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs);
 void bdrv_round_to_clusters(BlockDriverState *bs,
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 57df069..3d7b446 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -205,6 +205,9 @@ int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
                                       int count, BdrvRequestFlags flags);
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
                           int count);
+int coroutine_fn blk_co_pwritev_compressed(BlockBackend *blk, int64_t offset,
+                                           unsigned int bytes,
+                                           QEMUIOVector *qiov);
 int blk_truncate(BlockBackend *blk, int64_t offset);
 int blk_discard(BlockBackend *blk, int64_t sector_num, int nb_sectors);
 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
-- 
2.1.4