[v20210111,15/39] tools/guest: save: move batch_pfns

Commit Message

Olaf Hering Jan. 11, 2021, 5:42 p.m. UTC

The batch_pfns array is already allocated in advance.
Move it into the preallocated area.

Signed-off-by: Olaf Hering <[e-mail]>
---
 tools/libs/guest/xg_sr_common.h |  2 +-
 tools/libs/guest/xg_sr_save.c   | 25 +++++++++++--------------
 2 files changed, 12 insertions(+), 15 deletions(-)

Comments

Ian Jackson Feb. 8, 2021, 5:46 p.m. UTC | #1

Olaf Hering writes ("[PATCH v20210111 15/39] tools/guest: save: move batch_pfns"):
> The batch_pfns array is already allocated in advance.
> Move it into the preallocated area.

I think these patche really need a review from someone who understands
the migration code.  Ideally, Andy, who unfortunately has been very
busy.

I doubt this is going to make it for 4.15 :-( but maybe Andy or
someone else has an opinion.

Thanks,
Ian.

Patch

diff --git a/tools/libs/guest/xg_sr_common.h b/tools/libs/guest/xg_sr_common.h
index 62bc87b5f4..c78a07b8f8 100644
--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -212,6 +212,7 @@  static inline int update_blob(struct xc_sr_blob *blob,
 }
 
 struct xc_sr_save_arrays {
+    xen_pfn_t batch_pfns[MAX_BATCH_SIZE];
 };
 
 struct xc_sr_restore_arrays {
@@ -249,7 +250,6 @@  struct xc_sr_context
 
             struct precopy_stats stats;
 
-            xen_pfn_t *batch_pfns;
             unsigned int nr_batch_pfns;
             unsigned long *deferred_pages;
             unsigned long nr_deferred_pages;
diff --git a/tools/libs/guest/xg_sr_save.c b/tools/libs/guest/xg_sr_save.c
index baaeb12762..700344b6b6 100644
--- a/tools/libs/guest/xg_sr_save.c
+++ b/tools/libs/guest/xg_sr_save.c
@@ -77,7 +77,7 @@  static int write_checkpoint_record(struct xc_sr_context *ctx)
 
 /*
  * Writes a batch of memory as a PAGE_DATA record into the stream.  The batch
- * is constructed in ctx->save.batch_pfns.
+ * is constructed in ctx->save.m->batch_pfns.
  *
  * This function:
  * - gets the types for each pfn in the batch.
@@ -128,12 +128,12 @@  static int write_batch(struct xc_sr_context *ctx)
     for ( i = 0; i < nr_pfns; ++i )
     {
         types[i] = mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
-                                                      ctx->save.batch_pfns[i]);
+                                                      ctx->save.m->batch_pfns[i]);
 
         /* Likely a ballooned page. */
         if ( mfns[i] == INVALID_MFN )
         {
-            set_bit(ctx->save.batch_pfns[i], ctx->save.deferred_pages);
+            set_bit(ctx->save.m->batch_pfns[i], ctx->save.deferred_pages);
             ++ctx->save.nr_deferred_pages;
         }
     }
@@ -179,7 +179,7 @@  static int write_batch(struct xc_sr_context *ctx)
             if ( errors[p] )
             {
                 ERROR("Mapping of pfn %#"PRIpfn" (mfn %#"PRIpfn") failed %d",
-                      ctx->save.batch_pfns[i], mfns[p], errors[p]);
+                      ctx->save.m->batch_pfns[i], mfns[p], errors[p]);
                 goto err;
             }
 
@@ -193,7 +193,7 @@  static int write_batch(struct xc_sr_context *ctx)
             {
                 if ( rc == -1 && errno == EAGAIN )
                 {
-                    set_bit(ctx->save.batch_pfns[i], ctx->save.deferred_pages);
+                    set_bit(ctx->save.m->batch_pfns[i], ctx->save.deferred_pages);
                     ++ctx->save.nr_deferred_pages;
                     types[i] = XEN_DOMCTL_PFINFO_XTAB;
                     --nr_pages;
@@ -224,7 +224,7 @@  static int write_batch(struct xc_sr_context *ctx)
     rec.length += nr_pages * PAGE_SIZE;
 
     for ( i = 0; i < nr_pfns; ++i )
-        rec_pfns[i] = ((uint64_t)(types[i]) << 32) | ctx->save.batch_pfns[i];
+        rec_pfns[i] = ((uint64_t)(types[i]) << 32) | ctx->save.m->batch_pfns[i];
 
     iov[0].iov_base = &rec.type;
     iov[0].iov_len = sizeof(rec.type);
@@ -296,9 +296,9 @@  static int flush_batch(struct xc_sr_context *ctx)
 
     if ( !rc )
     {
-        VALGRIND_MAKE_MEM_UNDEFINED(ctx->save.batch_pfns,
+        VALGRIND_MAKE_MEM_UNDEFINED(ctx->save.m->batch_pfns,
                                     MAX_BATCH_SIZE *
-                                    sizeof(*ctx->save.batch_pfns));
+                                    sizeof(*ctx->save.m->batch_pfns));
     }
 
     return rc;
@@ -315,7 +315,7 @@  static int add_to_batch(struct xc_sr_context *ctx, xen_pfn_t pfn)
         rc = flush_batch(ctx);
 
     if ( rc == 0 )
-        ctx->save.batch_pfns[ctx->save.nr_batch_pfns++] = pfn;
+        ctx->save.m->batch_pfns[ctx->save.nr_batch_pfns++] = pfn;
 
     return rc;
 }
@@ -850,14 +850,12 @@  static int setup(struct xc_sr_context *ctx)
 
     dirty_bitmap = xc_hypercall_buffer_alloc_pages(
         xch, dirty_bitmap, NRPAGES(bitmap_size(ctx->save.p2m_size)));
-    ctx->save.batch_pfns = malloc(MAX_BATCH_SIZE *
-                                  sizeof(*ctx->save.batch_pfns));
     ctx->save.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
     ctx->save.m = malloc(sizeof(*ctx->save.m));
 
-    if ( !ctx->save.m || !ctx->save.batch_pfns || !dirty_bitmap || !ctx->save.deferred_pages )
+    if ( !ctx->save.m || !dirty_bitmap || !ctx->save.deferred_pages )
     {
-        ERROR("Unable to allocate memory for dirty bitmaps, batch pfns and"
+        ERROR("Unable to allocate memory for dirty bitmaps and"
               " deferred pages");
         rc = -1;
         errno = ENOMEM;
@@ -886,7 +884,6 @@  static void cleanup(struct xc_sr_context *ctx)
     xc_hypercall_buffer_free_pages(xch, dirty_bitmap,
                                    NRPAGES(bitmap_size(ctx->save.p2m_size)));
     free(ctx->save.deferred_pages);
-    free(ctx->save.batch_pfns);
     free(ctx->save.m);
 }