Re: [PATCH v3 1/6] block: add bitmap-populate job
[reviving an old thread]
On 6/22/20 4:44 PM, Eric Blake wrote:
On 6/19/20 11:16 PM, Vladimir Sementsov-Ogievskiy wrote:
19.06.2020 22:56, Eric Blake wrote:
From: John Snow
This job copies the allocation map into a bitmap. It's a job because
there's no guarantee that allocation interrogation will be quick (or
won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
It was designed with different possible population patterns in mind,
but only top layer allocation was implemented for now.
Signed-off-by: John Snow
Signed-off-by: Eric Blake
---
+{ 'struct': 'BlockDirtyBitmapPopulate',
+ 'base': 'BlockDirtyBitmap',
+ 'data': { 'job-id': 'str',
+ 'pattern': 'BitmapPattern',
As written, "pattern":"allocate-top" is rather limited - it can only
grab allocation from the top node. Being able to grab the allocation
from a specific node may indeed be more useful. Another bitmap patterns
that might be useful would be an all-one pattern (create a bitmap that
treats the entire disk as dirty). I also remember brainstorming with
John the question of whether we want bitmap-populate to have different
mask modes: does the population perform an overwrite (the bitmap now
matches the source pattern exactly, even if some bits were set and
others cleared), a union merge (any bits already set in the bitmap
remain set, additional bits are set according to pattern), or even a
difference (any bits already cleared in the bitmap remain clear, while
bits in the pattern can also clear additional bits in the bitmap).
If I understand Peter's goals, the initial libvirt use is a union mode
(keep bits in the bitmap that are already set, but set additional bits
according to the population pattern).
+ '*on-error': 'BlockdevOnError',
+ '*auto-finalize': 'bool',
+ '*auto-dismiss': 'bool' } }
+
Peter said about a possibility of populating several target bitmaps
simultaneously.
What about such a generalized semantics:
Merge all sources to each target
@targets: list of bitmaps to be populated by the job
{ 'struct': 'BlockDirtyBitmapPopulate',
'data': { ,
'targets': ['BlockDirtyBitmap'],
'sources': ['BitmapPopulateSource'] } }
We still need the 'pattern' argument (the idea being that if we have:
Base <- Active, we want to be able to merge in the allocation map of
Active into bitmaps stored in Base as part of a commit operation,
whether that is active commit of a live guest or offline commit while
the guest is offline). Having an array for 'targets' to merge into is
fine, but for 'sources', it's less a concern about selecting from
multiple sources, and more a concern about selecting the allocation
pattern to be merged in (libvirt wants to merge the same allocation
pattern into each bitmap in Base). Generalizing things to allow the
merge of more than one source at once might not hurt, but I'm not sure
we need it yet.
But when it comes to multiple destinations or multiple sources, while it
seems like it might be a convenience factor, I also worry that it is
over-engineering. See more below...
But there are other patterns that we may want to support: an all-ones
pattern, or maybe a pattern that tracks known-zeros instead of allocation.
@bitmap: specify dirty bitmap to be merged to target bitamp(s)
@node: specify a node name, which allocation-map is to be merged to
target bitmap(s)
{ 'alternate': 'BitmapPopulateSource',
'data': { 'bitmap': 'BlockDirtyBitmap',
'node': 'str' } }
This design is clever in that it lets us merge in both existing bitmaps
and using a node-name for merging in an allocation map instead of a
bitmap; but it limits us to only one pattern. Better might be something
where we supply a union (hmm, we've had proposals in the past for a
default value to the discriminator to allow it to be optional, so I'll
proceed as if we will finally implement that):
{ 'enum': 'BitmapPattern', 'data': [ 'bitmap', 'allocation-top' ] }
{ 'union': 'BitmapPopulateSource',
'base': { '*pattern': 'BitmapPattern' },
'discriminator': { 'name': 'pattern', 'default': 'bitmap' },
'data': { 'bitmap': 'BitmapPopulateSource',
'allocation-top': { 'node': 'str' } } }
so that you can then do:
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b1" },
{ "node": "base", "name": "b2" } ],
"sources": [ { "pattern": "allocation-top", "node": "top" } ]
} }
to merge in the allocation information of top into multiple bitmaps of
base at once,
Hmm, I left out the mandatory "job-id" parameter here; one of the key
points of the new command is that some patterns (like allocation) may
involve potentially lengthy I/O, so we need a job-id (the existing
block-dirty-bitmap-merge does not). But since the existing
block-dirty-bitmap-merge supports multiple sources to one destination,
Re: [PATCH v3 1/6] block: add bitmap-populate job
Am 19.06.2020 um 21:56 hat Eric Blake geschrieben:
> From: John Snow
>
> This job copies the allocation map into a bitmap. It's a job because
> there's no guarantee that allocation interrogation will be quick (or
> won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
>
> It was designed with different possible population patterns in mind,
> but only top layer allocation was implemented for now.
>
> Signed-off-by: John Snow
> Signed-off-by: Eric Blake
> +BlockJob *bitpop_job_create(
> +const char *job_id,
> +BlockDriverState *bs,
> +BdrvDirtyBitmap *target_bitmap,
> +BitmapPattern pattern,
> +BlockdevOnError on_error,
> +int creation_flags,
> +BlockCompletionFunc *cb,
> +void *opaque,
> +JobTxn *txn,
> +Error **errp)
> +{
> +int64_t len;
> +BitpopBlockJob *job = NULL;
> +int64_t cluster_size;
> +BdrvDirtyBitmap *new_bitmap = NULL;
> +
> +assert(bs);
> +assert(target_bitmap);
> +
> +if (!bdrv_is_inserted(bs)) {
> +error_setg(errp, "Device is not inserted: %s",
> + bdrv_get_device_name(bs));
> +return NULL;
> +}
> +
> +if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> +return NULL;
> +}
So did we decide that we'll keep the legacy op blocker with the type of
another block job even though nobody could tell what it's good for?
Kevin
Re: [PATCH v3 1/6] block: add bitmap-populate job
23.06.2020 00:44, Eric Blake wrote:
On 6/19/20 11:16 PM, Vladimir Sementsov-Ogievskiy wrote:
19.06.2020 22:56, Eric Blake wrote:
From: John Snow
This job copies the allocation map into a bitmap. It's a job because
there's no guarantee that allocation interrogation will be quick (or
won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
It was designed with different possible population patterns in mind,
but only top layer allocation was implemented for now.
Signed-off-by: John Snow
Signed-off-by: Eric Blake
---
+{ 'struct': 'BlockDirtyBitmapPopulate',
+ 'base': 'BlockDirtyBitmap',
+ 'data': { 'job-id': 'str',
+ 'pattern': 'BitmapPattern',
+ '*on-error': 'BlockdevOnError',
+ '*auto-finalize': 'bool',
+ '*auto-dismiss': 'bool' } }
+
Peter said about a possibility of populating several target bitmaps
simultaneously.
What about such a generalized semantics:
Merge all sources to each target
@targets: list of bitmaps to be populated by the job
{ 'struct': 'BlockDirtyBitmapPopulate',
'data': { ,
'targets': ['BlockDirtyBitmap'],
'sources': ['BitmapPopulateSource'] } }
We still need the 'pattern' argument (the idea being that if we have: Base <-
Active, we want to be able to merge in the allocation map of Active into bitmaps
stored in Base as part of a commit operation, whether that is active commit of a
live guest or offline commit while the guest is offline). Having an array for
'targets' to merge into is fine, but for 'sources', it's less a concern about
selecting from multiple sources, and more a concern about selecting the allocation
pattern to be merged in (libvirt wants to merge the same allocation pattern into
each bitmap in Base). Generalizing things to allow the merge of more than one
source at once might not hurt, but I'm not sure we need it yet.
But there are other patterns that we may want to support: an all-ones pattern,
or maybe a pattern that tracks known-zeros instead of allocation.
@bitmap: specify dirty bitmap to be merged to target bitamp(s)
@node: specify a node name, which allocation-map is to be merged to target
bitmap(s)
{ 'alternate': 'BitmapPopulateSource',
'data': { 'bitmap': 'BlockDirtyBitmap',
'node': 'str' } }
This design is clever in that it lets us merge in both existing bitmaps and
using a node-name for merging in an allocation map instead of a bitmap; but it
limits us to only one pattern.
Ah, yes, we can't discriminate by type node-name from 'all-ones' or something
like this.
Better might be something where we supply a union (hmm, we've had proposals in
the past for a default value to the discriminator to allow it to be optional,
so I'll proceed as if we will finally implement that):
{ 'enum': 'BitmapPattern', 'data': [ 'bitmap', 'allocation-top' ] }
{ 'union': 'BitmapPopulateSource',
'base': { '*pattern': 'BitmapPattern' },
'discriminator': { 'name': 'pattern', 'default': 'bitmap' },
'data': { 'bitmap': 'BitmapPopulateSource',
'allocation-top': { 'node': 'str' } } }
Yes, this is better, of course.
so that you can then do:
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b1" },
{ "node": "base", "name": "b2" } ],
"sources": [ { "pattern": "allocation-top", "node": "top" } ]
} }
to merge in the allocation information of top into multiple bitmaps of base at
once, or conversely, do:
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b1" } ],
"sources": [ { "pattern": "bitmap",
"node": "top", "name": "b1" } ]
} }
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b2" } ],
"sources": [ { "node": "top", "name": "b2" } ]
} }
and of course, wrap this in a "transaction" to ensure that it all succeeds or
fails as a unit, rather than messing up one bitmap if another fails, while also allowing
future extension for additional patterns.
- so, we can merge several bitmaps together with several allocation maps into
several target bitmaps.
(I remember, we also said about a possibility of starting several populating
jobs, populating into
same bitmap, I think it may be substituted by one job with several sources.
Still, it's not hard to
allow to use target bitmaps in a several jobs simultaneously and this is not
about the QAPI interface)
Will this simplify things in libvirt?
Peter, in your preliminary experiments with block-dirty-bitmap-populate, did
you ever need to start more than one job to a single bitmap destination, or was
it merely starting multiple jobs because you had multiple destinations but
always just a single source?
--
Best regards,
Vladimir
Re: [PATCH v3 1/6] block: add bitmap-populate job
On 6/19/20 11:16 PM, Vladimir Sementsov-Ogievskiy wrote:
19.06.2020 22:56, Eric Blake wrote:
From: John Snow
This job copies the allocation map into a bitmap. It's a job because
there's no guarantee that allocation interrogation will be quick (or
won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
It was designed with different possible population patterns in mind,
but only top layer allocation was implemented for now.
Signed-off-by: John Snow
Signed-off-by: Eric Blake
---
+{ 'struct': 'BlockDirtyBitmapPopulate',
+ 'base': 'BlockDirtyBitmap',
+ 'data': { 'job-id': 'str',
+ 'pattern': 'BitmapPattern',
+ '*on-error': 'BlockdevOnError',
+ '*auto-finalize': 'bool',
+ '*auto-dismiss': 'bool' } }
+
Peter said about a possibility of populating several target bitmaps
simultaneously.
What about such a generalized semantics:
Merge all sources to each target
@targets: list of bitmaps to be populated by the job
{ 'struct': 'BlockDirtyBitmapPopulate',
'data': { ,
'targets': ['BlockDirtyBitmap'],
'sources': ['BitmapPopulateSource'] } }
We still need the 'pattern' argument (the idea being that if we have:
Base <- Active, we want to be able to merge in the allocation map of
Active into bitmaps stored in Base as part of a commit operation,
whether that is active commit of a live guest or offline commit while
the guest is offline). Having an array for 'targets' to merge into is
fine, but for 'sources', it's less a concern about selecting from
multiple sources, and more a concern about selecting the allocation
pattern to be merged in (libvirt wants to merge the same allocation
pattern into each bitmap in Base). Generalizing things to allow the
merge of more than one source at once might not hurt, but I'm not sure
we need it yet.
But there are other patterns that we may want to support: an all-ones
pattern, or maybe a pattern that tracks known-zeros instead of allocation.
@bitmap: specify dirty bitmap to be merged to target bitamp(s)
@node: specify a node name, which allocation-map is to be merged to
target bitmap(s)
{ 'alternate': 'BitmapPopulateSource',
'data': { 'bitmap': 'BlockDirtyBitmap',
'node': 'str' } }
This design is clever in that it lets us merge in both existing bitmaps
and using a node-name for merging in an allocation map instead of a
bitmap; but it limits us to only one pattern. Better might be something
where we supply a union (hmm, we've had proposals in the past for a
default value to the discriminator to allow it to be optional, so I'll
proceed as if we will finally implement that):
{ 'enum': 'BitmapPattern', 'data': [ 'bitmap', 'allocation-top' ] }
{ 'union': 'BitmapPopulateSource',
'base': { '*pattern': 'BitmapPattern' },
'discriminator': { 'name': 'pattern', 'default': 'bitmap' },
'data': { 'bitmap': 'BitmapPopulateSource',
'allocation-top': { 'node': 'str' } } }
so that you can then do:
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b1" },
{ "node": "base", "name": "b2" } ],
"sources": [ { "pattern": "allocation-top", "node": "top" } ]
} }
to merge in the allocation information of top into multiple bitmaps of
base at once, or conversely, do:
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b1" } ],
"sources": [ { "pattern": "bitmap",
"node": "top", "name": "b1" } ]
} }
{ "execute": "block-dirty-bitmap-populate",
"arguments": { "targets": [ { "node": "base", "name": "b2" } ],
"sources": [ { "node": "top", "name": "b2" } ]
} }
and of course, wrap this in a "transaction" to ensure that it all
succeeds or fails as a unit, rather than messing up one bitmap if
another fails, while also allowing future extension for additional patterns.
- so, we can merge several bitmaps together with several allocation maps
into several target bitmaps.
(I remember, we also said about a possibility of starting several
populating jobs, populating into
same bitmap, I think it may be substituted by one job with several
sources. Still, it's not hard to
allow to use target bitmaps in a several jobs simultaneously and this
is not about the QAPI interface)
Will this simplify things in libvirt?
Peter, in your preliminary experiments with block-dirty-bitmap-populate,
did you ever need to start more than one job to a single bitmap
destination, or was it merely starting multiple jobs because you had
multiple destinations but always just a single source?
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
Re: [PATCH v3 1/6] block: add bitmap-populate job
19.06.2020 22:56, Eric Blake wrote:
From: John Snow
This job copies the allocation map into a bitmap. It's a job because
there's no guarantee that allocation interrogation will be quick (or
won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
It was designed with different possible population patterns in mind,
but only top layer allocation was implemented for now.
Signed-off-by: John Snow
Signed-off-by: Eric Blake
---
qapi/block-core.json | 48 +
qapi/job.json | 6 +-
include/block/block_int.h | 21
block/bitmap-populate.c | 207 ++
blockjob.c| 3 +-
MAINTAINERS | 1 +
block/Makefile.objs | 1 +
7 files changed, 285 insertions(+), 2 deletions(-)
create mode 100644 block/bitmap-populate.c
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0e1c6a59f228..a1bcdba04423 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2211,6 +2211,54 @@
{ 'command': 'block-dirty-bitmap-merge',
'data': 'BlockDirtyBitmapMerge' }
+##
+# @BitmapPattern:
+#
+# An enumeration of possible patterns that can be written into a bitmap.
+#
+# @allocation-top: The allocation status of the top layer
+# of the attached storage node.
+#
+# Since: 5.1
+##
+{ 'enum': 'BitmapPattern',
+ 'data': ['allocation-top'] }
+
+##
+# @BlockDirtyBitmapPopulate:
+#
+# @job-id: identifier for the newly-created block job.
+#
+# @pattern: What pattern should be written into the bitmap?
+#
+# @on-error: the action to take if an error is encountered on a bitmap's
+#attached node, default 'report'.
+#'stop' and 'enospc' can only be used if the block device supports
+#io-status (see BlockInfo).
+#
+# @auto-finalize: When false, this job will wait in a PENDING state after it
has
+# finished its work, waiting for @block-job-finalize before
+# making any block graph changes.
+# When true, this job will automatically
+# perform its abort or commit actions.
+# Defaults to true.
+#
+# @auto-dismiss: When false, this job will wait in a CONCLUDED state after it
+#has completely ceased all work, and awaits @block-job-dismiss.
+#When true, this job will automatically disappear from the
query
+#list without user intervention.
+#Defaults to true.
+#
+# Since: 5.1
+##
+{ 'struct': 'BlockDirtyBitmapPopulate',
+ 'base': 'BlockDirtyBitmap',
+ 'data': { 'job-id': 'str',
+'pattern': 'BitmapPattern',
+'*on-error': 'BlockdevOnError',
+'*auto-finalize': 'bool',
+'*auto-dismiss': 'bool' } }
+
Peter said about a possibility of populating several target bitmaps
simultaneously.
What about such a generalized semantics:
Merge all sources to each target
@targets: list of bitmaps to be populated by the job
{ 'struct': 'BlockDirtyBitmapPopulate',
'data': { ,
'targets': ['BlockDirtyBitmap'],
'sources': ['BitmapPopulateSource'] } }
@bitmap: specify dirty bitmap to be merged to target bitamp(s)
@node: specify a node name, which allocation-map is to be merged to target
bitmap(s)
{ 'alternate': 'BitmapPopulateSource',
'data': { 'bitmap': 'BlockDirtyBitmap',
'node': 'str' } }
- so, we can merge several bitmaps together with several allocation maps into
several target bitmaps.
(I remember, we also said about a possibility of starting several populating
jobs, populating into
same bitmap, I think it may be substituted by one job with several sources.
Still, it's not hard to
allow to use target bitmaps in a several jobs simultaneously and this is not
about the QAPI interface)
Will this simplify things in libvirt?
--
Best regards,
Vladimir
[PATCH v3 1/6] block: add bitmap-populate job
From: John Snow
This job copies the allocation map into a bitmap. It's a job because
there's no guarantee that allocation interrogation will be quick (or
won't hang), so it cannot be retrofitted into block-dirty-bitmap-merge.
It was designed with different possible population patterns in mind,
but only top layer allocation was implemented for now.
Signed-off-by: John Snow
Signed-off-by: Eric Blake
---
qapi/block-core.json | 48 +
qapi/job.json | 6 +-
include/block/block_int.h | 21
block/bitmap-populate.c | 207 ++
blockjob.c| 3 +-
MAINTAINERS | 1 +
block/Makefile.objs | 1 +
7 files changed, 285 insertions(+), 2 deletions(-)
create mode 100644 block/bitmap-populate.c
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 0e1c6a59f228..a1bcdba04423 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2211,6 +2211,54 @@
{ 'command': 'block-dirty-bitmap-merge',
'data': 'BlockDirtyBitmapMerge' }
+##
+# @BitmapPattern:
+#
+# An enumeration of possible patterns that can be written into a bitmap.
+#
+# @allocation-top: The allocation status of the top layer
+# of the attached storage node.
+#
+# Since: 5.1
+##
+{ 'enum': 'BitmapPattern',
+ 'data': ['allocation-top'] }
+
+##
+# @BlockDirtyBitmapPopulate:
+#
+# @job-id: identifier for the newly-created block job.
+#
+# @pattern: What pattern should be written into the bitmap?
+#
+# @on-error: the action to take if an error is encountered on a bitmap's
+#attached node, default 'report'.
+#'stop' and 'enospc' can only be used if the block device supports
+#io-status (see BlockInfo).
+#
+# @auto-finalize: When false, this job will wait in a PENDING state after it
has
+# finished its work, waiting for @block-job-finalize before
+# making any block graph changes.
+# When true, this job will automatically
+# perform its abort or commit actions.
+# Defaults to true.
+#
+# @auto-dismiss: When false, this job will wait in a CONCLUDED state after it
+#has completely ceased all work, and awaits @block-job-dismiss.
+#When true, this job will automatically disappear from the
query
+#list without user intervention.
+#Defaults to true.
+#
+# Since: 5.1
+##
+{ 'struct': 'BlockDirtyBitmapPopulate',
+ 'base': 'BlockDirtyBitmap',
+ 'data': { 'job-id': 'str',
+'pattern': 'BitmapPattern',
+'*on-error': 'BlockdevOnError',
+'*auto-finalize': 'bool',
+'*auto-dismiss': 'bool' } }
+
##
# @BlockDirtyBitmapSha256:
#
diff --git a/qapi/job.json b/qapi/job.json
index 5e658281f5c4..33ff3500f794 100644
--- a/qapi/job.json
+++ b/qapi/job.json
@@ -19,10 +19,14 @@
#
# @create: image creation job type, see "blockdev-create" (since 3.0)
#
+# @bitmap-populate: drive bitmap population job type, see
+# "block-dirty-bitmap-populate" (since 5.1)
+#
# Since: 1.7
##
{ 'enum': 'JobType',
- 'data': ['commit', 'stream', 'mirror', 'backup', 'create'] }
+ 'data': ['commit', 'stream', 'mirror', 'backup', 'create',
+ 'bitmap-populate'] }
##
# @JobStatus:
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 791de6a59c2c..93fb886e7e97 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1231,6 +1231,27 @@ BlockJob *backup_job_create(const char *job_id,
BlockDriverState *bs,
BlockCompletionFunc *cb, void *opaque,
JobTxn *txn, Error **errp);
+/*
+ * bitpop_job_create: Create a new bitmap population job.
+ *
+ * @job_id: The id of the newly-created job.
+ * @bs: Block device associated with the @target_bitmap.
+ * @target_bitmap: The bitmap to populate.
+ * @on_error: What to do if an error on @bs is encountered.
+ * @creation_flags: Flags that control the behavior of the Job lifetime.
+ * See @BlockJobCreateFlags
+ * @cb: Completion function for the job.
+ * @opaque: Opaque pointer value passed to @cb.
+ * @txn: Transaction that this job is part of (may be NULL).
+ */
+BlockJob *bitpop_job_create(const char *job_id, BlockDriverState *bs,
+BdrvDirtyBitmap *target_bitmap,
+BitmapPattern pattern,
+BlockdevOnError on_error,
+int creation_flags,
+BlockCompletionFunc *cb, void *opaque,
+JobTxn *txn, Error **errp);
+
BdrvChild *bdrv_root_attach_child(BlockDriverState *child_bs,
const char *child_name,
const BdrvChildClass *child_class,
diff --git a/block/bitmap-populate.c b/block/bitmap-populate.c
new file mode 100644
index
