[PATCH v20210616 23/36] tools: restore: move pfns array in populate_pfns

[Olaf Hering <olaf@xxxxxxxxx>]

Remove allocation from hotpath, move populate_pfns' pfns array into 
preallocated space.
Use some prefix to avoid conflict with an array used in handle_page_data.

Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/libs/saverestore/common.h  |  1 +
 tools/libs/saverestore/restore.c | 11 +----------
 2 files changed, 2 insertions(+), 10 deletions(-)

diff --git a/tools/libs/saverestore/common.h b/tools/libs/saverestore/common.h
index 3cfb23861f..379887e149 100644
--- a/tools/libs/saverestore/common.h
+++ b/tools/libs/saverestore/common.h
@@ -244,6 +244,7 @@ struct sr_restore_arrays {
     int map_errs[MAX_BATCH_SIZE];
     /* populate_pfns */
     xen_pfn_t pp_mfns[MAX_BATCH_SIZE];
+    xen_pfn_t pp_pfns[MAX_BATCH_SIZE];
 };
 
 struct xc_sr_context
diff --git a/tools/libs/saverestore/restore.c b/tools/libs/saverestore/restore.c
index 0c29478ccb..f2234eac55 100644
--- a/tools/libs/saverestore/restore.c
+++ b/tools/libs/saverestore/restore.c
@@ -139,17 +139,10 @@ int populate_pfns(struct xc_sr_context *ctx, unsigned int 
count,
 {
     xc_interface *xch = ctx->xch;
     xen_pfn_t *mfns = ctx->restore.m->pp_mfns,
-        *pfns = malloc(count * sizeof(*pfns));
+        *pfns = ctx->restore.m->pp_pfns;
     unsigned int i, nr_pfns = 0;
     int rc = -1;
 
-    if ( !pfns )
-    {
-        ERROR("Failed to allocate %zu bytes for populating the physmap",
-              2 * count * sizeof(*mfns));
-        goto err;
-    }
-
     for ( i = 0; i < count; ++i )
     {
         if ( (!types ||
@@ -190,8 +183,6 @@ int populate_pfns(struct xc_sr_context *ctx, unsigned int 
count,
     rc = 0;
 
  err:
-    free(pfns);
-
     return rc;
 }