File xen.sr-save-mfns.patch of Package xen
From: Olaf Hering <olaf@aepfle.de>
Date: Fri, 23 Oct 2020 11:20:36 +0200
Subject: sr save mfns
tools: save: preallocate mfns array
Remove repeated allocation from migration loop. There will never be
more than MAX_BATCH_SIZE pages to process in a batch, see add_to_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 | 25 +++++----
2 files changed, 14 insertions(+), 12 deletions(-)
--- a/tools/libs/guest/xg_sr_common.h
+++ b/tools/libs/guest/xg_sr_common.h
@@ -235,24 +235,25 @@ struct xc_sr_context
bool live;
/* 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;
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
@@ -79,116 +79,115 @@ 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.
*
* 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;
- xen_pfn_t *mfns = NULL, *types = NULL;
+ xen_pfn_t *types = NULL;
void *guest_mapping = NULL;
void **guest_data = NULL;
void **local_pages = NULL;
int *errors = NULL, 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);
- /* Mfns of the batch pfns. */
- mfns = malloc(nr_pfns * sizeof(*mfns));
/* 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. */
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 ( !mfns || !types || !errors || !guest_data || !local_pages || !iov )
+ if ( !types || !errors || !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 )
{
- types[i] = mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
+ types[i] = ctx->save.mfns[i] = ctx->save.ops.pfn_to_gfn(ctx,
ctx->save.batch_pfns[i]);
/* Likely a ballooned page. */
- if ( mfns[i] == INVALID_MFN )
+ if ( ctx->save.mfns[i] == INVALID_MFN )
{
set_bit(ctx->save.batch_pfns[i], ctx->save.deferred_pages);
++ctx->save.nr_deferred_pages;
}
}
rc = xc_get_pfn_type_batch(xch, ctx->domid, nr_pfns, types);
if ( rc )
{
PERROR("Failed to get types for pfn batch");
goto err;
}
rc = -1;
for ( i = 0; i < nr_pfns; ++i )
{
if ( !is_known_page_type(types[i]) )
{
- ERROR("Unknown type %#"PRIpfn" for pfn %#"PRIpfn, types[i], mfns[i]);
+ ERROR("Unknown type %#"PRIpfn" for pfn %#"PRIpfn,
+ types[i], ctx->save.mfns[i]);
goto err;
}
if ( !page_type_has_stream_data(types[i]) )
continue;
- mfns[nr_pages++] = mfns[i];
+ 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, mfns, errors);
+ xch->fmem, ctx->domid, PROT_READ, nr_pages, ctx->save.mfns, 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(types[i]) )
continue;
if ( errors[p] )
{
ERROR("Mapping of pfn %#"PRIpfn" (mfn %#"PRIpfn") failed %d",
- ctx->save.batch_pfns[i], mfns[p], errors[p]);
+ ctx->save.batch_pfns[i], ctx->save.mfns[p], errors[p]);
goto err;
}
orig_page = page = guest_mapping + (p * PAGE_SIZE);
rc = ctx->save.ops.normalise_page(ctx, types[i], &page);
if ( orig_page != page )
local_pages[i] = page;
if ( rc )
{
if ( rc == -1 && errno == EAGAIN )
@@ -268,25 +267,24 @@ static int write_batch(struct xc_sr_context *ctx)
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);
free(types);
- free(mfns);
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 )
@@ -841,27 +839,29 @@ static int setup(struct xc_sr_context *ctx)
int rc;
DECLARE_HYPERCALL_BUFFER_SHADOW(unsigned long, dirty_bitmap,
&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.deferred_pages = bitmap_alloc(ctx->save.p2m_size);
- if ( !ctx->save.batch_pfns || !dirty_bitmap || !ctx->save.deferred_pages )
+ if ( !ctx->save.batch_pfns || !ctx->save.mfns ||
+ !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;
@@ -874,24 +874,25 @@ 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.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;
IPRINTF("Saving domain %d, type %s",
