| Message ID | 20221011215559.602584-2-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | migration: Postcopy Preempt-Full | expand |
* Peter Xu (peterx@redhat.com) wrote: > Any call to ram_find_and_save_block() needs to take the bitmap mutex. We > used to not take it for most of ram_save_complete() because we thought > we're the only one left using the bitmap, but it's not true after the > preempt full patchset applied, since the return path can be taking it too. > > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > migration/ram.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/migration/ram.c b/migration/ram.c > index 1338e47665..cfeb571800 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -3406,6 +3406,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque) > /* try transferring iterative blocks of memory */ > > /* flush all remaining blocks regardless of rate limiting */ > + qemu_mutex_lock(&rs->bitmap_mutex); > while (true) { > int pages; > > @@ -3419,6 +3420,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque) > break; > } > } > + qemu_mutex_unlock(&rs->bitmap_mutex); > > flush_compressed_data(rs); > ram_control_after_iterate(f, RAM_CONTROL_FINISH); > -- > 2.37.3 >
Peter Xu <peterx@redhat.com> wrote: > Any call to ram_find_and_save_block() needs to take the bitmap mutex. We > used to not take it for most of ram_save_complete() because we thought > we're the only one left using the bitmap, but it's not true after the > preempt full patchset applied, since the return path can be taking it too. > > Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com>
diff --git a/migration/ram.c b/migration/ram.c index 1338e47665..cfeb571800 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -3406,6 +3406,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque) /* try transferring iterative blocks of memory */ /* flush all remaining blocks regardless of rate limiting */ + qemu_mutex_lock(&rs->bitmap_mutex); while (true) { int pages; @@ -3419,6 +3420,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque) break; } } + qemu_mutex_unlock(&rs->bitmap_mutex); flush_compressed_data(rs); ram_control_after_iterate(f, RAM_CONTROL_FINISH);
Any call to ram_find_and_save_block() needs to take the bitmap mutex. We used to not take it for most of ram_save_complete() because we thought we're the only one left using the bitmap, but it's not true after the preempt full patchset applied, since the return path can be taking it too. Signed-off-by: Peter Xu <peterx@redhat.com> --- migration/ram.c | 2 ++ 1 file changed, 2 insertions(+)