[PATCH v20210616 13/36] tools: save: move types array

[Olaf Hering <olaf@xxxxxxxxx>]

Remove allocation from hotpath, move types array into preallocated space.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/libs/saverestore/common.h | 2 ++
 tools/libs/saverestore/save.c   | 7 ++-----
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/tools/libs/saverestore/common.h b/tools/libs/saverestore/common.h
index 6129710a3f..1df684acb9 100644
--- a/tools/libs/saverestore/common.h
+++ b/tools/libs/saverestore/common.h
@@ -227,6 +227,8 @@ struct sr_save_arrays {
     xen_pfn_t batch_pfns[MAX_BATCH_SIZE];
     /* write_batch: Mfns of the batch pfns. */
     xen_pfn_t mfns[MAX_BATCH_SIZE];
+    /* write_batch: Types of the batch pfns. */
+    xen_pfn_t types[MAX_BATCH_SIZE];
 };
 
 struct sr_restore_arrays {
diff --git a/tools/libs/saverestore/save.c b/tools/libs/saverestore/save.c
index 6b09784be8..0883c1fac0 100644
--- a/tools/libs/saverestore/save.c
+++ b/tools/libs/saverestore/save.c
@@ -88,7 +88,7 @@ static int write_checkpoint_record(struct xc_sr_context *ctx)
 static int write_batch(struct xc_sr_context *ctx)
 {
     xc_interface *xch = ctx->xch;
-    xen_pfn_t *mfns = ctx->save.m->mfns, *types = NULL;
+    xen_pfn_t *mfns = ctx->save.m->mfns, *types = ctx->save.m->types;
     void *guest_mapping = NULL;
     void **guest_data = NULL;
     void **local_pages = NULL;
@@ -105,8 +105,6 @@ static int write_batch(struct xc_sr_context *ctx)
 
     assert(nr_pfns != 0);
 
-    /* Types of the batch pfns. */
-    types = malloc(nr_pfns * sizeof(*types));
     /* Errors from attempting to map the gfns. */
     errors = malloc(nr_pfns * sizeof(*errors));
     /* Pointers to page data to send.  Mapped gfns or local allocations. */
@@ -116,7 +114,7 @@ static int write_batch(struct xc_sr_context *ctx)
     /* iovec[] for writev(). */
     iov = malloc((nr_pfns + 4) * sizeof(*iov));
 
-    if ( !types || !errors || !guest_data || !local_pages || !iov )
+    if ( !errors || !guest_data || !local_pages || !iov )
     {
         ERROR("Unable to allocate arrays for a batch of %u pages",
               nr_pfns);
@@ -274,7 +272,6 @@ static int write_batch(struct xc_sr_context *ctx)
     free(local_pages);
     free(guest_data);
     free(errors);
-    free(types);
 
     return rc;
 }