xen/libxc-sr-save-types.patch

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From: Olaf Hering <olaf@aepfle.de>
Date: Fri, 23 Oct 2020 11:23:51 +0200
Subject: libxc sr save types
tools: save: preallocate types 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 | 28 +++++++++++++---------------
2 files changed, 14 insertions(+), 15 deletions(-)
--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -245,6 +245,7 @@ struct xc_sr_context
xen_pfn_t *batch_pfns;
xen_pfn_t *mfns;
+ xen_pfn_t *types;
unsigned int nr_batch_pfns;
unsigned long *deferred_pages;
unsigned long nr_deferred_pages;
--- a/tools/libs/guest/xg_sr_save.c
+++ b/tools/libs/guest/xg_sr_save.c
@@ -88,7 +88,6 @@ static int write_checkpoint_record(struc
static int write_batch(struct xc_sr_context *ctx)
{
xc_interface *xch = ctx->xch;
- xen_pfn_t *types = NULL;
void *guest_mapping = NULL;
void **guest_data = NULL;
void **local_pages = NULL;
@@ -105,8 +104,6 @@ static int write_batch(struct xc_sr_cont
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 +113,7 @@ static int write_batch(struct xc_sr_cont
/* 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);
@@ -125,7 +122,7 @@ static int write_batch(struct xc_sr_cont
for ( i = 0; i < nr_pfns; ++i )
{
- types[i] = ctx->save.mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
+ ctx->save.types[i] = ctx->save.mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
ctx->save.batch_pfns[i]);
/* Likely a ballooned page. */
@@ -136,7 +133,7 @@ static int write_batch(struct xc_sr_cont
}
}
- rc = xc_get_pfn_type_batch(xch, ctx->domid, nr_pfns, types);
+ rc = xc_get_pfn_type_batch(xch, ctx->domid, nr_pfns, ctx->save.types);
if ( rc )
{
PERROR("Failed to get types for pfn batch");
@@ -146,14 +143,14 @@ static int write_batch(struct xc_sr_cont
for ( i = 0; i < nr_pfns; ++i )
{
- if ( !is_known_page_type(types[i]) )
+ if ( !is_known_page_type(ctx->save.types[i]) )
{
ERROR("Unknown type %#"PRIpfn" for pfn %#"PRIpfn,
- types[i], ctx->save.mfns[i]);
+ ctx->save.types[i], ctx->save.mfns[i]);
goto err;
}
- if ( !page_type_has_stream_data(types[i]) )
+ if ( !page_type_has_stream_data(ctx->save.types[i]) )
continue;
ctx->save.mfns[nr_pages++] = ctx->save.mfns[i];
@@ -172,7 +169,7 @@ static int write_batch(struct xc_sr_cont
for ( i = 0, p = 0; i < nr_pfns; ++i )
{
- if ( !page_type_has_stream_data(types[i]) )
+ if ( !page_type_has_stream_data(ctx->save.types[i]) )
continue;
if ( errors[p] )
@@ -183,7 +180,7 @@ static int write_batch(struct xc_sr_cont
}
orig_page = page = guest_mapping + (p * PAGE_SIZE);
- rc = ctx->save.ops.normalise_page(ctx, types[i], &page);
+ rc = ctx->save.ops.normalise_page(ctx, ctx->save.types[i], &page);
if ( orig_page != page )
local_pages[i] = page;
@@ -194,7 +191,7 @@ static int write_batch(struct xc_sr_cont
{
set_bit(ctx->save.batch_pfns[i], ctx->save.deferred_pages);
++ctx->save.nr_deferred_pages;
- types[i] = XEN_DOMCTL_PFINFO_XTAB;
+ ctx->save.types[i] = XEN_DOMCTL_PFINFO_XTAB;
--nr_pages;
}
else
@@ -223,7 +220,7 @@ static int write_batch(struct xc_sr_cont
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)(ctx->save.types[i]) << 32) | ctx->save.batch_pfns[i];
iov[0].iov_base = &rec.type;
iov[0].iov_len = sizeof(rec.type);
@@ -275,7 +272,6 @@ static int write_batch(struct xc_sr_cont
free(local_pages);
free(guest_data);
free(errors);
- free(types);
return rc;
}
@@ -849,9 +845,10 @@ static int setup(struct xc_sr_context *c
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.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
- if ( !ctx->save.batch_pfns || !ctx->save.mfns ||
+ if ( !ctx->save.batch_pfns || !ctx->save.mfns || !ctx->save.types ||
!dirty_bitmap || !ctx->save.deferred_pages )
{
ERROR("Unable to allocate memory for dirty bitmaps, batch pfns and"
@@ -883,6 +880,7 @@ static void cleanup(struct xc_sr_context
xc_hypercall_buffer_free_pages(xch, dirty_bitmap,
NRPAGES(bitmap_size(ctx->save.p2m_size)));
free(ctx->save.deferred_pages);
+ free(ctx->save.types);
free(ctx->save.mfns);
free(ctx->save.batch_pfns);
}