* Re: [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration
2017-02-08 14:28 [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration Ashijeet Acharya
@ 2017-02-08 16:00 ` Dr. David Alan Gilbert
2017-02-08 21:48 ` Philippe Mathieu-Daudé
2017-02-10 15:16 ` Dr. David Alan Gilbert
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2017-02-08 16:00 UTC (permalink / raw)
To: Ashijeet Acharya; +Cc: thuth, quintela, berrange, pbonzini, groug, qemu-devel
* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote:
> Migration of a "none" machine with no RAM crashes abruptly as
> bitmap_new() fails and thus aborts. Instead place zero RAM checks at
> appropriate places to skip migration of RAM in this case and complete
> migration successfully for devices only.
>
> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> Changes in v3:
> - handle migration cleanup appropriately (Dave)
> Changes in v2:
> - try to migrate successfully by skipping RAM (Paolo, Greg)
> - drop the idea of erroring out and failing nicely
> ---
> migration/ram.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index ef8fadf..faff5ab 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
> ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in
> ram_addr_t space */
>
> + /* No dirty page as there is zero RAM */
> + if (!ram_bytes_total()) {
> + return pages;
> + }
> +
> pss.block = last_seen_block;
> pss.offset = last_offset;
> pss.complete_round = false;
> @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void)
> bytes_transferred = 0;
> reset_ram_globals();
>
> - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
> - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> -
> - if (migrate_postcopy_ram()) {
> - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + /* Skip setting bitmap if there is no RAM */
> + if (ram_bytes_total()) {
> + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> +
> + if (migrate_postcopy_ram()) {
> + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + }
> }
>
> /*
> --
> 2.6.2
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration
2017-02-08 14:28 [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration Ashijeet Acharya
2017-02-08 16:00 ` Dr. David Alan Gilbert
@ 2017-02-08 21:48 ` Philippe Mathieu-Daudé
2017-02-10 15:16 ` Dr. David Alan Gilbert
2 siblings, 0 replies; 4+ messages in thread
From: Philippe Mathieu-Daudé @ 2017-02-08 21:48 UTC (permalink / raw)
To: qemu-devel; +Cc: Ashijeet Acharya, thuth, quintela, groug, pbonzini, dgilbert
On 02/08/2017 11:28 AM, Ashijeet Acharya wrote:
> Migration of a "none" machine with no RAM crashes abruptly as
> bitmap_new() fails and thus aborts. Instead place zero RAM checks at
> appropriate places to skip migration of RAM in this case and complete
> migration successfully for devices only.
>
> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> Changes in v3:
> - handle migration cleanup appropriately (Dave)
> Changes in v2:
> - try to migrate successfully by skipping RAM (Paolo, Greg)
> - drop the idea of erroring out and failing nicely
> ---
> migration/ram.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index ef8fadf..faff5ab 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
> ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in
> ram_addr_t space */
>
> + /* No dirty page as there is zero RAM */
> + if (!ram_bytes_total()) {
> + return pages;
> + }
> +
> pss.block = last_seen_block;
> pss.offset = last_offset;
> pss.complete_round = false;
> @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void)
> bytes_transferred = 0;
> reset_ram_globals();
>
> - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
> - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> -
> - if (migrate_postcopy_ram()) {
> - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + /* Skip setting bitmap if there is no RAM */
> + if (ram_bytes_total()) {
> + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> +
> + if (migrate_postcopy_ram()) {
> + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + }
> }
>
> /*
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration
2017-02-08 14:28 [Qemu-devel] [PATCH v3] migrate: Introduce zero RAM checks to skip RAM migration Ashijeet Acharya
2017-02-08 16:00 ` Dr. David Alan Gilbert
2017-02-08 21:48 ` Philippe Mathieu-Daudé
@ 2017-02-10 15:16 ` Dr. David Alan Gilbert
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert @ 2017-02-10 15:16 UTC (permalink / raw)
To: Ashijeet Acharya; +Cc: thuth, quintela, berrange, pbonzini, groug, qemu-devel
* Ashijeet Acharya (ashijeetacharya@gmail.com) wrote:
> Migration of a "none" machine with no RAM crashes abruptly as
> bitmap_new() fails and thus aborts. Instead place zero RAM checks at
> appropriate places to skip migration of RAM in this case and complete
> migration successfully for devices only.
>
> Signed-off-by: Ashijeet Acharya <ashijeetacharya@gmail.com>
Queued.
> ---
> Changes in v3:
> - handle migration cleanup appropriately (Dave)
> Changes in v2:
> - try to migrate successfully by skipping RAM (Paolo, Greg)
> - drop the idea of erroring out and failing nicely
> ---
> migration/ram.c | 22 +++++++++++++++-------
> 1 file changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index ef8fadf..faff5ab 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -1325,6 +1325,11 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage,
> ram_addr_t dirty_ram_abs; /* Address of the start of the dirty page in
> ram_addr_t space */
>
> + /* No dirty page as there is zero RAM */
> + if (!ram_bytes_total()) {
> + return pages;
> + }
> +
> pss.block = last_seen_block;
> pss.offset = last_offset;
> pss.complete_round = false;
> @@ -1912,14 +1917,17 @@ static int ram_save_init_globals(void)
> bytes_transferred = 0;
> reset_ram_globals();
>
> - ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
> - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> -
> - if (migrate_postcopy_ram()) {
> - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + /* Skip setting bitmap if there is no RAM */
> + if (ram_bytes_total()) {
> + ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> + migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> +
> + if (migrate_postcopy_ram()) {
> + migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + }
> }
>
> /*
> --
> 2.6.2
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 4+ messages in thread