Re: [PATCH 16/21] parallels: naive implementation of allocate_clusters with used bitmap
On 9/18/23 15:14, Denis V. Lunev wrote:
On 9/18/23 15:09, Alexander Ivanov wrote:
On 9/15/23 20:41, Denis V. Lunev wrote:
The access to the bitmap is not optimized completely.
Signed-off-by: Denis V. Lunev
---
block/parallels.c | 51
---
1 file changed, 39 insertions(+), 12 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index a6d2f05863..2efa578e21 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -253,7 +253,7 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
{
int ret = 0;
BDRVParallelsState *s = bs->opaque;
- int64_t pos, space, idx, to_allocate, i, len;
+ int64_t i, pos, idx, to_allocate, first_free, host_off;
pos = block_status(s, sector_num, nb_sectors, pnum);
if (pos > 0) {
@@ -276,15 +276,13 @@ allocate_clusters(BlockDriverState *bs,
int64_t sector_num,
*/
assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);
- space = to_allocate * s->tracks;
- len = bdrv_co_getlength(bs->file->bs);
- if (len < 0) {
- return len;
- }
- if (s->data_end + space > (len >> BDRV_SECTOR_BITS)) {
+ first_free = find_first_zero_bit(s->used_bmap, s->used_bmap_size);
+ if (first_free == s->used_bmap_size) {
uint32_t new_usedsize;
+ int64_t space = to_allocate * s->tracks + s->prealloc_size;
+
+ host_off = s->data_end * BDRV_SECTOR_SIZE;
- space += s->prealloc_size;
/*
* We require the expanded size to read back as zero. If the
* user permitted truncation, we try that; but if it
fails, we
@@ -313,6 +311,32 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
s->used_bmap = bitmap_zero_extend(s->used_bmap,
s->used_bmap_size,
new_usedsize);
s->used_bmap_size = new_usedsize;
+ } else {
+ int64_t next_used;
+ next_used = find_next_bit(s->used_bmap, s->used_bmap_size,
first_free);
+
+ /* Not enough continuous clusters in the middle, adjust the
size */
+ if (next_used - first_free < to_allocate) {
+ to_allocate = next_used - first_free;
+ *pnum = (idx + to_allocate) * s->tracks - sector_num;
It looks, we can write this simplier:
*pnum = to_allocate * s->tracks;
because idx and sector_num aren't changed from idx calculation:
idx = sector_num / s->tracks;
absolutely NO! sector_num can be unaligned. Here we get to the
situation when the end of the operation is aligned to cluster
and is calculated above.
Den
OK, now I got the idea.
Reviewed-by: Alexander Ivanov
Re: [PATCH 16/21] parallels: naive implementation of allocate_clusters with used bitmap
On 9/18/23 15:09, Alexander Ivanov wrote:
On 9/15/23 20:41, Denis V. Lunev wrote:
The access to the bitmap is not optimized completely.
Signed-off-by: Denis V. Lunev
---
block/parallels.c | 51 ---
1 file changed, 39 insertions(+), 12 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index a6d2f05863..2efa578e21 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -253,7 +253,7 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
{
int ret = 0;
BDRVParallelsState *s = bs->opaque;
- int64_t pos, space, idx, to_allocate, i, len;
+ int64_t i, pos, idx, to_allocate, first_free, host_off;
pos = block_status(s, sector_num, nb_sectors, pnum);
if (pos > 0) {
@@ -276,15 +276,13 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
*/
assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);
- space = to_allocate * s->tracks;
- len = bdrv_co_getlength(bs->file->bs);
- if (len < 0) {
- return len;
- }
- if (s->data_end + space > (len >> BDRV_SECTOR_BITS)) {
+ first_free = find_first_zero_bit(s->used_bmap, s->used_bmap_size);
+ if (first_free == s->used_bmap_size) {
uint32_t new_usedsize;
+ int64_t space = to_allocate * s->tracks + s->prealloc_size;
+
+ host_off = s->data_end * BDRV_SECTOR_SIZE;
- space += s->prealloc_size;
/*
* We require the expanded size to read back as zero. If the
* user permitted truncation, we try that; but if it fails, we
@@ -313,6 +311,32 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
s->used_bmap = bitmap_zero_extend(s->used_bmap,
s->used_bmap_size,
new_usedsize);
s->used_bmap_size = new_usedsize;
+ } else {
+ int64_t next_used;
+ next_used = find_next_bit(s->used_bmap, s->used_bmap_size,
first_free);
+
+ /* Not enough continuous clusters in the middle, adjust the
size */
+ if (next_used - first_free < to_allocate) {
+ to_allocate = next_used - first_free;
+ *pnum = (idx + to_allocate) * s->tracks - sector_num;
It looks, we can write this simplier:
*pnum = to_allocate * s->tracks;
because idx and sector_num aren't changed from idx calculation:
idx = sector_num / s->tracks;
absolutely NO! sector_num can be unaligned. Here we get to the
situation when the end of the operation is aligned to cluster
and is calculated above.
Den
Re: [PATCH 16/21] parallels: naive implementation of allocate_clusters with used bitmap
On 9/15/23 20:41, Denis V. Lunev wrote:
The access to the bitmap is not optimized completely.
Signed-off-by: Denis V. Lunev
---
block/parallels.c | 51 ---
1 file changed, 39 insertions(+), 12 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index a6d2f05863..2efa578e21 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -253,7 +253,7 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
{
int ret = 0;
BDRVParallelsState *s = bs->opaque;
-int64_t pos, space, idx, to_allocate, i, len;
+int64_t i, pos, idx, to_allocate, first_free, host_off;
pos = block_status(s, sector_num, nb_sectors, pnum);
if (pos > 0) {
@@ -276,15 +276,13 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
*/
assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);
-space = to_allocate * s->tracks;
-len = bdrv_co_getlength(bs->file->bs);
-if (len < 0) {
-return len;
-}
-if (s->data_end + space > (len >> BDRV_SECTOR_BITS)) {
+first_free = find_first_zero_bit(s->used_bmap, s->used_bmap_size);
+if (first_free == s->used_bmap_size) {
uint32_t new_usedsize;
+int64_t space = to_allocate * s->tracks + s->prealloc_size;
+
+host_off = s->data_end * BDRV_SECTOR_SIZE;
-space += s->prealloc_size;
/*
* We require the expanded size to read back as zero. If the
* user permitted truncation, we try that; but if it fails, we
@@ -313,6 +311,32 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
s->used_bmap = bitmap_zero_extend(s->used_bmap, s->used_bmap_size,
new_usedsize);
s->used_bmap_size = new_usedsize;
+} else {
+int64_t next_used;
+next_used = find_next_bit(s->used_bmap, s->used_bmap_size, first_free);
+
+/* Not enough continuous clusters in the middle, adjust the size */
+if (next_used - first_free < to_allocate) {
+to_allocate = next_used - first_free;
+*pnum = (idx + to_allocate) * s->tracks - sector_num;
It looks, we can write this simplier:
*pnum = to_allocate * s->tracks;
because idx and sector_num aren't changed from idx calculation:
idx = sector_num / s->tracks;
+}
+
+host_off = s->data_start * BDRV_SECTOR_SIZE;
+host_off += first_free * s->cluster_size;
+
+/*
+ * No need to preallocate if we are using tail area from the above
+ * branch. In the other case we are likely re-using hole. Preallocate
+ * the space if required by the prealloc_mode.
+ */
+if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE &&
+host_off < s->data_end * BDRV_SECTOR_SIZE) {
+ret = bdrv_co_pwrite_zeroes(bs->file, host_off,
+s->cluster_size * to_allocate, 0);
+if (ret < 0) {
+return ret;
+}
+}
}
/*
@@ -344,15 +368,18 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
}
}
-ret = mark_used(bs, s->used_bmap, s->used_bmap_size,
-s->data_end << BDRV_SECTOR_BITS, to_allocate);
+ret = mark_used(bs, s->used_bmap, s->used_bmap_size, host_off,
to_allocate);
if (ret < 0) {
/* Image consistency is broken. Alarm! */
return ret;
}
for (i = 0; i < to_allocate; i++) {
-parallels_set_bat_entry(s, idx + i, s->data_end / s->off_multiplier);
-s->data_end += s->tracks;
+parallels_set_bat_entry(s, idx + i,
+host_off / BDRV_SECTOR_SIZE / s->off_multiplier);
+host_off += s->cluster_size;
+}
+if (host_off > s->data_end * BDRV_SECTOR_SIZE) {
+s->data_end = host_off / BDRV_SECTOR_SIZE;
}
return bat2sect(s, idx) + sector_num % s->tracks;
--
Best regards,
Alexander Ivanov
[PATCH 16/21] parallels: naive implementation of allocate_clusters with used bitmap
The access to the bitmap is not optimized completely.
Signed-off-by: Denis V. Lunev
---
block/parallels.c | 51 ---
1 file changed, 39 insertions(+), 12 deletions(-)
diff --git a/block/parallels.c b/block/parallels.c
index a6d2f05863..2efa578e21 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -253,7 +253,7 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
{
int ret = 0;
BDRVParallelsState *s = bs->opaque;
-int64_t pos, space, idx, to_allocate, i, len;
+int64_t i, pos, idx, to_allocate, first_free, host_off;
pos = block_status(s, sector_num, nb_sectors, pnum);
if (pos > 0) {
@@ -276,15 +276,13 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
*/
assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);
-space = to_allocate * s->tracks;
-len = bdrv_co_getlength(bs->file->bs);
-if (len < 0) {
-return len;
-}
-if (s->data_end + space > (len >> BDRV_SECTOR_BITS)) {
+first_free = find_first_zero_bit(s->used_bmap, s->used_bmap_size);
+if (first_free == s->used_bmap_size) {
uint32_t new_usedsize;
+int64_t space = to_allocate * s->tracks + s->prealloc_size;
+
+host_off = s->data_end * BDRV_SECTOR_SIZE;
-space += s->prealloc_size;
/*
* We require the expanded size to read back as zero. If the
* user permitted truncation, we try that; but if it fails, we
@@ -313,6 +311,32 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
s->used_bmap = bitmap_zero_extend(s->used_bmap, s->used_bmap_size,
new_usedsize);
s->used_bmap_size = new_usedsize;
+} else {
+int64_t next_used;
+next_used = find_next_bit(s->used_bmap, s->used_bmap_size, first_free);
+
+/* Not enough continuous clusters in the middle, adjust the size */
+if (next_used - first_free < to_allocate) {
+to_allocate = next_used - first_free;
+*pnum = (idx + to_allocate) * s->tracks - sector_num;
+}
+
+host_off = s->data_start * BDRV_SECTOR_SIZE;
+host_off += first_free * s->cluster_size;
+
+/*
+ * No need to preallocate if we are using tail area from the above
+ * branch. In the other case we are likely re-using hole. Preallocate
+ * the space if required by the prealloc_mode.
+ */
+if (s->prealloc_mode == PRL_PREALLOC_MODE_FALLOCATE &&
+host_off < s->data_end * BDRV_SECTOR_SIZE) {
+ret = bdrv_co_pwrite_zeroes(bs->file, host_off,
+s->cluster_size * to_allocate, 0);
+if (ret < 0) {
+return ret;
+}
+}
}
/*
@@ -344,15 +368,18 @@ allocate_clusters(BlockDriverState *bs, int64_t
sector_num,
}
}
-ret = mark_used(bs, s->used_bmap, s->used_bmap_size,
-s->data_end << BDRV_SECTOR_BITS, to_allocate);
+ret = mark_used(bs, s->used_bmap, s->used_bmap_size, host_off,
to_allocate);
if (ret < 0) {
/* Image consistency is broken. Alarm! */
return ret;
}
for (i = 0; i < to_allocate; i++) {
-parallels_set_bat_entry(s, idx + i, s->data_end / s->off_multiplier);
-s->data_end += s->tracks;
+parallels_set_bat_entry(s, idx + i,
+host_off / BDRV_SECTOR_SIZE / s->off_multiplier);
+host_off += s->cluster_size;
+}
+if (host_off > s->data_end * BDRV_SECTOR_SIZE) {
+s->data_end = host_off / BDRV_SECTOR_SIZE;
}
return bat2sect(s, idx) + sector_num % s->tracks;
--
2.34.1
