| Message ID | 1433174959-7176-2-git-send-email-mreitz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 01.06.2015 18:09, Max Reitz wrote: > The L2 cache must cover at least two L2 tables, because during COW two > L2 tables are accessed simultaneously. > > Reported-by: Alexander Graf <agraf@suse.de> > Cc: qemu-stable <qemu-stable@nongnu.org> > Signed-off-by: Max Reitz <mreitz@redhat.com> > --- > block/qcow2.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/qcow2.h b/block/qcow2.h > index 0076512..aa20022 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -62,7 +62,8 @@ > #define MIN_CLUSTER_BITS 9 > #define MAX_CLUSTER_BITS 21 > > -#define MIN_L2_CACHE_SIZE 1 /* cluster */ > +/* Must be at least 2 to cover COW */ > +#define MIN_L2_CACHE_SIZE 2 /* clusters */ > > /* Must be at least 4 to cover all cases of refcount table growth */ > #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ Of course git send-email ignored the qemu-stable line... CC-ing manually. Max
On 01.06.15 18:09, Max Reitz wrote: > The L2 cache must cover at least two L2 tables, because during COW two > L2 tables are accessed simultaneously. > > Reported-by: Alexander Graf <agraf@suse.de> > Cc: qemu-stable <qemu-stable@nongnu.org> > Signed-off-by: Max Reitz <mreitz@redhat.com> Tested-by: Alexander Graf <agraf@suse.de> Alex > --- > block/qcow2.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/block/qcow2.h b/block/qcow2.h > index 0076512..aa20022 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -62,7 +62,8 @@ > #define MIN_CLUSTER_BITS 9 > #define MAX_CLUSTER_BITS 21 > > -#define MIN_L2_CACHE_SIZE 1 /* cluster */ > +/* Must be at least 2 to cover COW */ > +#define MIN_L2_CACHE_SIZE 2 /* clusters */ > > /* Must be at least 4 to cover all cases of refcount table growth */ > #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ >
On Mon 01 Jun 2015 06:09:17 PM CEST, Max Reitz <mreitz@redhat.com> wrote: > The L2 cache must cover at least two L2 tables, because during COW two > L2 tables are accessed simultaneously. > > Reported-by: Alexander Graf <agraf@suse.de> > Cc: qemu-stable <qemu-stable@nongnu.org> > Signed-off-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Berto
diff --git a/block/qcow2.h b/block/qcow2.h index 0076512..aa20022 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -62,7 +62,8 @@ #define MIN_CLUSTER_BITS 9 #define MAX_CLUSTER_BITS 21 -#define MIN_L2_CACHE_SIZE 1 /* cluster */ +/* Must be at least 2 to cover COW */ +#define MIN_L2_CACHE_SIZE 2 /* clusters */ /* Must be at least 4 to cover all cases of refcount table growth */ #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
The L2 cache must cover at least two L2 tables, because during COW two L2 tables are accessed simultaneously. Reported-by: Alexander Graf <agraf@suse.de> Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Max Reitz <mreitz@redhat.com> --- block/qcow2.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)