Remove allocation from hotpath, move guest_data array into preallocated space.
Because this was allocated with calloc: Adjust the loop to clear unused entries as needed. Signed-off-by: Olaf Hering <o...@aepfle.de> --- tools/libs/guest/xg_sr_common.h | 2 ++ tools/libs/guest/xg_sr_save.c | 11 ++++++----- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/tools/libs/guest/xg_sr_common.h b/tools/libs/guest/xg_sr_common.h index 81158a4f4d..33e66678c6 100644 --- a/tools/libs/guest/xg_sr_common.h +++ b/tools/libs/guest/xg_sr_common.h @@ -223,6 +223,8 @@ struct xc_sr_save_arrays { struct iovec iov[MAX_BATCH_SIZE + 4]; /* write_batch */ uint64_t rec_pfns[MAX_BATCH_SIZE]; + /* write_batch: Pointers to page data to send. Mapped gfns or local allocations. */ + void *guest_data[MAX_BATCH_SIZE]; }; struct xc_sr_restore_arrays { diff --git a/tools/libs/guest/xg_sr_save.c b/tools/libs/guest/xg_sr_save.c index 4d7fbe09ed..658f834ae8 100644 --- a/tools/libs/guest/xg_sr_save.c +++ b/tools/libs/guest/xg_sr_save.c @@ -90,7 +90,7 @@ static int write_batch(struct xc_sr_context *ctx) xc_interface *xch = ctx->xch; xen_pfn_t *mfns = ctx->save.m->mfns, *types = ctx->save.m->types; void *guest_mapping = NULL; - void **guest_data = NULL; + void **guest_data = ctx->save.m->guest_data; void **local_pages = NULL; int *errors = ctx->save.m->errors, rc = -1; unsigned int i, p, nr_pages = 0, nr_pages_mapped = 0; @@ -105,12 +105,10 @@ static int write_batch(struct xc_sr_context *ctx) assert(nr_pfns != 0); - /* 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)); - if ( !guest_data || !local_pages ) + if ( !local_pages ) { ERROR("Unable to allocate arrays for a batch of %u pages", nr_pfns); @@ -166,7 +164,10 @@ static int write_batch(struct xc_sr_context *ctx) for ( i = 0, p = 0; i < nr_pfns; ++i ) { if ( page_type_has_stream_data(types[i]) == false ) + { + guest_data[i] = NULL; continue; + } if ( errors[p] ) { @@ -183,6 +184,7 @@ static int write_batch(struct xc_sr_context *ctx) if ( rc ) { + guest_data[i] = NULL; if ( rc == -1 && errno == EAGAIN ) { set_bit(ctx->save.m->batch_pfns[i], ctx->save.deferred_pages); @@ -256,7 +258,6 @@ static int write_batch(struct xc_sr_context *ctx) for ( i = 0; local_pages && i < nr_pfns; ++i ) free(local_pages[i]); free(local_pages); - free(guest_data); return rc; }