File xen.sr-save-errors.patch of Package xen

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File xen.sr-save-errors.patch of Package xen

From: Olaf Hering <olaf@aepfle.de>
Date: Fri, 23 Oct 2020 11:26:05 +0200
Subject: sr save errors

tools: save: preallocate errors array

Remove repeated allocation from migration loop. There will never be
more than MAX_BATCH_SIZE pages to process in a batch.
Allocate the space once.

Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
 tools/libs/guest/xg_sr_common.h |  1 +
 tools/libs/guest/xg_sr_save.c   | 20 ++++-----
 2 files changed, 11 insertions(+), 10 deletions(-)

--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -237,24 +237,25 @@ struct xc_sr_context
             /* Further debugging information in the stream. */
             bool debug;
 
             unsigned long p2m_size;
             size_t pages_sent;
             size_t overhead_sent;
 
             struct precopy_stats stats;
 
             xen_pfn_t *batch_pfns;
             xen_pfn_t *mfns;
             xen_pfn_t *types;
+            int *errors;
             unsigned int nr_batch_pfns;
             unsigned long *deferred_pages;
             unsigned long nr_deferred_pages;
             xc_hypercall_buffer_t dirty_bitmap_hbuf;
         } save;
 
         struct /* Restore data. */
         {
             struct xc_sr_restore_ops ops;
             struct restore_callbacks *callbacks;
 
             int send_back_fd;
--- a/tools/libs/guest/xg_sr_save.c
+++ b/tools/libs/guest/xg_sr_save.c
@@ -82,47 +82,45 @@ static int write_checkpoint_record(struct xc_sr_context *ctx)
  * This function:
  * - gets the types for each pfn in the batch.
  * - for each pfn with real data:
  *   - maps and attempts to localise the pages.
  * - construct and writes a PAGE_DATA record into the stream.
  */
 static int write_batch(struct xc_sr_context *ctx)
 {
     xc_interface *xch = ctx->xch;
     void *guest_mapping = NULL;
     void **guest_data = NULL;
     void **local_pages = NULL;
-    int *errors = NULL, rc = -1;
+    int rc = -1;
     unsigned int i, p, nr_pages = 0, nr_pages_mapped = 0;
     unsigned int nr_pfns = ctx->save.nr_batch_pfns;
     void *page, *orig_page;
     uint64_t *rec_pfns = NULL;
     struct iovec *iov = NULL; int iovcnt = 0;
     struct xc_sr_rec_page_data_header hdr = { 0 };
     struct xc_sr_record rec = {
         .type = REC_TYPE_PAGE_DATA,
     };
 
     assert(nr_pfns != 0);
 
-    /* Errors from attempting to map the gfns. */
-    errors = malloc(nr_pfns * sizeof(*errors));
     /* Pointers to page data to send.  Mapped gfns or local allocations. */
     guest_data = calloc(nr_pfns, sizeof(*guest_data));
     /* Pointers to locally allocated pages.  Need freeing. */
     local_pages = calloc(nr_pfns, sizeof(*local_pages));
     /* iovec[] for writev(). */
     iov = malloc((nr_pfns + 4) * sizeof(*iov));
 
-    if ( !errors || !guest_data || !local_pages || !iov )
+    if ( !guest_data || !local_pages || !iov )
     {
         ERROR("Unable to allocate arrays for a batch of %u pages",
               nr_pfns);
         goto err;
     }
 
     for ( i = 0; i < nr_pfns; ++i )
     {
         ctx->save.types[i] = ctx->save.mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
                                                       ctx->save.batch_pfns[i]);
 
         /* Likely a ballooned page. */
@@ -149,42 +147,43 @@ static int write_batch(struct xc_sr_context *ctx)
                   ctx->save.types[i], ctx->save.mfns[i]);
             goto err;
         }
 
         if ( !page_type_has_stream_data(ctx->save.types[i]) )
             continue;
 
         ctx->save.mfns[nr_pages++] = ctx->save.mfns[i];
     }
 
     if ( nr_pages > 0 )
     {
-        guest_mapping = xenforeignmemory_map(
-            xch->fmem, ctx->domid, PROT_READ, nr_pages, ctx->save.mfns, errors);
+        guest_mapping = xenforeignmemory_map(xch->fmem, ctx->domid, PROT_READ,
+            nr_pages, ctx->save.mfns, ctx->save.errors);
         if ( !guest_mapping )
         {
             PERROR("Failed to map guest pages");
             goto err;
         }
         nr_pages_mapped = nr_pages;
 
         for ( i = 0, p = 0; i < nr_pfns; ++i )
         {
             if ( !page_type_has_stream_data(ctx->save.types[i]) )
                 continue;
 
-            if ( errors[p] )
+            if ( ctx->save.errors[p] )
             {
                 ERROR("Mapping of pfn %#"PRIpfn" (mfn %#"PRIpfn") failed %d",
-                      ctx->save.batch_pfns[i], ctx->save.mfns[p], errors[p]);
+                      ctx->save.batch_pfns[i], ctx->save.mfns[p],
+                      ctx->save.errors[p]);
                 goto err;
             }
 
             orig_page = page = guest_mapping + (p * PAGE_SIZE);
             rc = ctx->save.ops.normalise_page(ctx, ctx->save.types[i], &page);
 
             if ( orig_page != page )
                 local_pages[i] = page;
 
             if ( rc )
             {
                 if ( rc == -1 && errno == EAGAIN )
@@ -262,25 +261,24 @@ static int write_batch(struct xc_sr_context *ctx)
     assert(nr_pages == 0);
     rc = ctx->save.nr_batch_pfns = 0;
 
  err:
     free(rec_pfns);
     if ( guest_mapping )
         xenforeignmemory_unmap(xch->fmem, guest_mapping, nr_pages_mapped);
     for ( i = 0; local_pages && i < nr_pfns; ++i )
         free(local_pages[i]);
     free(iov);
     free(local_pages);
     free(guest_data);
-    free(errors);
 
     return rc;
 }
 
 /*
  * Flush a batch of pfns into the stream.
  */
 static int flush_batch(struct xc_sr_context *ctx)
 {
     int rc = 0;
 
     if ( ctx->save.nr_batch_pfns == 0 )
@@ -837,28 +835,29 @@ static int setup(struct xc_sr_context *ctx)
                                     &ctx->save.dirty_bitmap_hbuf);
 
     rc = ctx->save.ops.setup(ctx);
     if ( rc )
         goto err;
 
     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.mfns = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.mfns));
     ctx->save.types = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.types));
+    ctx->save.errors = malloc(MAX_BATCH_SIZE * sizeof(*ctx->save.errors));
     ctx->save.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
 
     if ( !ctx->save.batch_pfns || !ctx->save.mfns || !ctx->save.types ||
-         !dirty_bitmap || !ctx->save.deferred_pages )
+         !ctx->save.errors || !dirty_bitmap || !ctx->save.deferred_pages )
     {
         ERROR("Unable to allocate memory for dirty bitmaps, batch pfns and"
               " deferred pages");
         rc = -1;
         errno = ENOMEM;
         goto err;
     }
 
     rc = 0;
 
  err:
     return rc;
@@ -871,24 +870,25 @@ static void cleanup(struct xc_sr_context *ctx)
                                     &ctx->save.dirty_bitmap_hbuf);
 
 
     xc_shadow_control(xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_OFF,
                       NULL, 0);
 
     if ( ctx->save.ops.cleanup(ctx) )
         PERROR("Failed to clean up");
 
     xc_hypercall_buffer_free_pages(xch, dirty_bitmap,
                                    NRPAGES(bitmap_size(ctx->save.p2m_size)));
     free(ctx->save.deferred_pages);
+    free(ctx->save.errors);
     free(ctx->save.types);
     free(ctx->save.mfns);
     free(ctx->save.batch_pfns);
 }
 
 /*
  * Save a domain.
  */
 static int save(struct xc_sr_context *ctx, uint16_t guest_type)
 {
     xc_interface *xch = ctx->xch;
     int rc, saved_rc = 0, saved_errno = 0;

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File xen.sr-save-errors.patch of Package xen

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