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Re: [Qemu-devel] [PATCH 1/2] savevm: split save/find loadvm_handlers ent
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] savevm: split save/find loadvm_handlers entry into two helper functions |
Date: |
Tue, 31 Jan 2017 10:04:33 +0000 |
User-agent: |
Mutt/1.7.1 (2016-10-04) |
* zhanghailiang (address@hidden) wrote:
> COLO's checkpoint process is based on migration process,
> everytime we do checkpoint we will repeat the process of savevm and loadvm.
>
> So we will call qemu_loadvm_section_start_full() repeatedly, It will
> add all migration sections information into loadvm_handlers list everytime,
> which will lead to memory leak.
>
> To fix it, we split the process of saving and finding section entry into two
> helper functions, we will check if section info was exist in loadvm_handlers
> list before save it.
>
> This modifications have no side effect for normal migration.
>
> Signed-off-by: zhanghailiang <address@hidden>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> ---
> migration/savevm.c | 55
> +++++++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 40 insertions(+), 15 deletions(-)
>
> diff --git a/migration/savevm.c b/migration/savevm.c
> index f9c06e9..92b3d6c 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1805,6 +1805,37 @@ void loadvm_free_handlers(MigrationIncomingState *mis)
> }
> }
>
> +static LoadStateEntry *loadvm_save_section_entry(MigrationIncomingState *mis,
Can you change that to loadvm_add_section_entry please; it's a bit
confusing using 'save' in a function name that's part of the 'load' path.
Dave
> + SaveStateEntry *se,
> + uint32_t section_id,
> + uint32_t version_id)
> +{
> + LoadStateEntry *le;
> +
> + /* Add entry */
> + le = g_malloc0(sizeof(*le));
> +
> + le->se = se;
> + le->section_id = section_id;
> + le->version_id = version_id;
> + QLIST_INSERT_HEAD(&mis->loadvm_handlers, le, entry);
> + return le;
> +}
> +
> +static LoadStateEntry *loadvm_find_section_entry(MigrationIncomingState *mis,
> + uint32_t section_id)
> +{
> + LoadStateEntry *le;
> +
> + QLIST_FOREACH(le, &mis->loadvm_handlers, entry) {
> + if (le->section_id == section_id) {
> + break;
> + }
> + }
> +
> + return le;
> +}
> +
> static int
> qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis)
> {
> @@ -1847,15 +1878,12 @@ qemu_loadvm_section_start_full(QEMUFile *f,
> MigrationIncomingState *mis)
> return -EINVAL;
> }
>
> - /* Add entry */
> - le = g_malloc0(sizeof(*le));
> -
> - le->se = se;
> - le->section_id = section_id;
> - le->version_id = version_id;
> - QLIST_INSERT_HEAD(&mis->loadvm_handlers, le, entry);
> -
> - ret = vmstate_load(f, le->se, le->version_id);
> + /* Check if we have saved this section info before, if not, save it */
> + le = loadvm_find_section_entry(mis, section_id);
> + if (!le) {
> + le = loadvm_save_section_entry(mis, se, section_id, version_id);
> + }
> + ret = vmstate_load(f, se, version_id);
> if (ret < 0) {
> error_report("error while loading state for instance 0x%x of"
> " device '%s'", instance_id, idstr);
> @@ -1878,12 +1906,9 @@ qemu_loadvm_section_part_end(QEMUFile *f,
> MigrationIncomingState *mis)
> section_id = qemu_get_be32(f);
>
> trace_qemu_loadvm_state_section_partend(section_id);
> - QLIST_FOREACH(le, &mis->loadvm_handlers, entry) {
> - if (le->section_id == section_id) {
> - break;
> - }
> - }
> - if (le == NULL) {
> +
> + le = loadvm_find_section_entry(mis, section_id);
> + if (!le) {
> error_report("Unknown savevm section %d", section_id);
> return -EINVAL;
> }
> --
> 1.8.3.1
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK