* [pbs-devel] [PATCH qemu] PVE: add zero block handling to PBS dump callback
@ 2020-08-13 11:50 Stefan Reiter
2020-08-19 13:42 ` [pbs-devel] applied: [pve-devel] " Thomas Lamprecht
0 siblings, 1 reply; 2+ messages in thread
From: Stefan Reiter @ 2020-08-13 11:50 UTC (permalink / raw)
To: pbs-devel, pve-devel
Both the PBS and VMA dump callbacks assume that a NULL pointer can be
passed as *pbuf, but that never happens, as backup-dump.c calls this
function with contents of an iovec.
So first, remove that assumption and add an 'assert' to verify.
Secondly, while the vma-writer already does the buffer_is_zero check
internally, for PBS we relied on that non-existant behaviour for zero
chunks, so do the buffer_is_zero check manually and pass NULL to the
rust lib in case it is true.
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
This increases backup speed to PBS for VMs with free space quite dramatically.
pve-backup.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/pve-backup.c b/pve-backup.c
index 40d8136f1a..7c99554514 100644
--- a/pve-backup.c
+++ b/pve-backup.c
@@ -8,6 +8,7 @@
#include "block/blockjob.h"
#include "qapi/qapi-commands-block.h"
#include "qapi/qmp/qerror.h"
+#include "qemu/cutils.h"
/* PVE backup state and related function */
@@ -136,10 +137,13 @@ pvebackup_co_dump_pbs_cb(
PVEBackupDevInfo *di = opaque;
assert(backup_state.pbs);
+ assert(buf);
Error *local_err = NULL;
int pbs_res = -1;
+ bool is_zero_block = size == di->block_size && buffer_is_zero(buf, size);
+
qemu_co_mutex_lock(&backup_state.dump_callback_mutex);
// avoid deadlock if job is cancelled
@@ -155,7 +159,8 @@ pvebackup_co_dump_pbs_cb(
uint64_t to_transfer = left < di->block_size ? left : di->block_size;
pbs_res = proxmox_backup_co_write_data(backup_state.pbs, di->dev_id,
- buf ? buf + transferred : NULL, start + transferred, to_transfer, &local_err);
+ is_zero_block ? NULL : buf + transferred, start + transferred,
+ to_transfer, &local_err);
transferred += to_transfer;
if (pbs_res < 0) {
@@ -168,7 +173,7 @@ pvebackup_co_dump_pbs_cb(
}
qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
- pvebackup_add_transfered_bytes(size, !buf ? size : 0, reused);
+ pvebackup_add_transfered_bytes(size, is_zero_block ? size : 0, reused);
return size;
}
@@ -190,6 +195,7 @@ pvebackup_co_dump_vma_cb(
int ret = -1;
assert(backup_state.vmaw);
+ assert(buf);
uint64_t remaining = size;
@@ -216,9 +222,7 @@ pvebackup_co_dump_vma_cb(
qemu_co_mutex_unlock(&backup_state.dump_callback_mutex);
++cluster_num;
- if (buf) {
- buf += VMA_CLUSTER_SIZE;
- }
+ buf += VMA_CLUSTER_SIZE;
if (ret < 0) {
Error *local_err = NULL;
vma_writer_error_propagate(backup_state.vmaw, &local_err);
--
2.20.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* [pbs-devel] applied: [pve-devel] [PATCH qemu] PVE: add zero block handling to PBS dump callback
2020-08-13 11:50 [pbs-devel] [PATCH qemu] PVE: add zero block handling to PBS dump callback Stefan Reiter
@ 2020-08-19 13:42 ` Thomas Lamprecht
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Lamprecht @ 2020-08-19 13:42 UTC (permalink / raw)
To: Proxmox VE development discussion, Stefan Reiter, pbs-devel
On 13.08.20 13:50, Stefan Reiter wrote:
> Both the PBS and VMA dump callbacks assume that a NULL pointer can be
> passed as *pbuf, but that never happens, as backup-dump.c calls this
> function with contents of an iovec.
>
> So first, remove that assumption and add an 'assert' to verify.
>
> Secondly, while the vma-writer already does the buffer_is_zero check
> internally, for PBS we relied on that non-existant behaviour for zero
> chunks, so do the buffer_is_zero check manually and pass NULL to the
> rust lib in case it is true.
>
> Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
> ---
>
> This increases backup speed to PBS for VMs with free space quite dramatically.
>
> pve-backup.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
>
applied, thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-08-13 11:50 [pbs-devel] [PATCH qemu] PVE: add zero block handling to PBS dump callback Stefan Reiter
2020-08-19 13:42 ` [pbs-devel] applied: [pve-devel] " Thomas Lamprecht
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