File libxc-sr-save-mfns.patch of Package xen.26341
From: Olaf Hering <olaf@aepfle.de>
Date: Fri, 23 Oct 2020 11:20:36 +0200
Subject: libxc sr save mfns
tools/guest: save: move mfns array
Remove allocation from hotpath, move mfns array into preallocated space.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
---
tools/libxc/xc_sr_common.h | 2 ++
tools/libxc/xc_sr_save.c | 7 ++-----
2 files changed, 4 insertions(+), 5 deletions(-)
--- xen-4.14.0-testing.orig/tools/libxc/xc_sr_common.h
+++ xen-4.14.0-testing/tools/libxc/xc_sr_common.h
@@ -214,6 +214,8 @@ static inline int update_blob(struct xc_
struct xc_sr_save_arrays {
xen_pfn_t batch_pfns[MAX_BATCH_SIZE];
+ /* write_batch: Mfns of the batch pfns. */
+ xen_pfn_t mfns[MAX_BATCH_SIZE];
};
struct xc_sr_restore_arrays {
--- xen-4.14.0-testing.orig/tools/libxc/xc_sr_save.c
+++ xen-4.14.0-testing/tools/libxc/xc_sr_save.c
@@ -88,7 +88,7 @@ static int write_checkpoint_record(struc
static int write_batch(struct xc_sr_context *ctx)
{
xc_interface *xch = ctx->xch;
- xen_pfn_t *mfns = NULL, *types = NULL;
+ xen_pfn_t *mfns = ctx->save.m->mfns, *types = NULL;
void *guest_mapping = NULL;
void **guest_data = NULL;
void **local_pages = NULL;
@@ -105,8 +105,6 @@ static int write_batch(struct xc_sr_cont
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. */
@@ -118,7 +116,7 @@ static int write_batch(struct xc_sr_cont
/* 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);
@@ -277,7 +275,6 @@ static int write_batch(struct xc_sr_cont
free(guest_data);
free(errors);
free(types);
- free(mfns);
return rc;
}