When receiving pages, look for contiguous 2-meg aligned regions and
attempt to allocate a superpage for that region, falling back to
4k pages if the allocation fails.
Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
diff -r f9bb0bbea7c2 -r 57558d87761f tools/libxc/xc_domain_restore.c
--- a/tools/libxc/xc_domain_restore.c Thu May 12 16:42:54 2011 +0100
+++ b/tools/libxc/xc_domain_restore.c Mon May 16 11:50:46 2011 +0100
@@ -48,6 +48,11 @@ struct restore_ctx {
#define HEARTBEAT_MS 1000
+#define SUPERPAGE_PFN_SHIFT 9
+#define SUPERPAGE_NR_PFNS (1UL << SUPERPAGE_PFN_SHIFT)
+
+#define SUPER_PAGE_START(pfn) (((pfn) & (SUPERPAGE_NR_PFNS-1)) == 0 )
+
#ifndef __MINIOS__
static ssize_t rdexact(xc_interface *xch, struct restore_ctx *ctx,
int fd, void* buf, size_t size)
@@ -882,9 +887,11 @@ static int pagebuf_get(xc_interface *xch
static int apply_batch(xc_interface *xch, uint32_t dom, struct restore_ctx
*ctx,
xen_pfn_t* region_mfn, unsigned long* pfn_type, int
pae_extended_cr3,
unsigned int hvm, struct xc_mmu* mmu,
- pagebuf_t* pagebuf, int curbatch)
+ pagebuf_t* pagebuf, int curbatch, int superpages)
{
int i, j, curpage, nr_mfns;
+ int k, scount;
+ unsigned long superpage_start=INVALID_P2M_ENTRY;
/* used by debug verify code */
unsigned long buf[PAGE_SIZE/sizeof(unsigned long)];
/* Our mapping of the current region (batch) */
@@ -902,8 +909,8 @@ static int apply_batch(xc_interface *xch
if (j > MAX_BATCH_SIZE)
j = MAX_BATCH_SIZE;
- /* First pass for this batch: work out how much memory to alloc */
- nr_mfns = 0;
+ /* First pass for this batch: work out how much memory to alloc, and
detect superpages */
+ nr_mfns = scount = 0;
for ( i = 0; i < j; i++ )
{
unsigned long pfn, pagetype;
@@ -914,19 +921,103 @@ static int apply_batch(xc_interface *xch
(ctx->p2m[pfn] == INVALID_P2M_ENTRY) )
{
/* Have a live PFN which hasn't had an MFN allocated */
+
+ /* Logic if we're in the middle of detecting a candidate superpage
*/
+ if ( superpage_start != INVALID_P2M_ENTRY )
+ {
+ /* Is this the next expected continuation? */
+ if ( pfn == superpage_start + scount )
+ {
+ if ( !superpages )
+ {
+ ERROR("Unexpexted codepath with no superpages");
+ return -1;
+ }
+
+ scount++;
+
+ /* If we've found a whole superpage, allocate it and
update p2m */
+ if ( scount == SUPERPAGE_NR_PFNS )
+ {
+ unsigned long supermfn;
+
+
+ supermfn=superpage_start;
+ if ( xc_domain_populate_physmap_exact(xch, dom, 1,
+ SUPERPAGE_PFN_SHIFT, 0, &supermfn) !=
0 )
+ {
+ DPRINTF("No 2M page available for pfn 0x%lx, fall
back to 4K page.\n",
+ superpage_start);
+ /* If we're falling back from a failed allocation,
subtract one
+ * from count, since the last page == pfn, which
will behandled
+ * anyway. */
+ scount--;
+ goto fallback;
+ }
+
+ DPRINTF("Mapping superpage (%d) pfn %lx, mfn %lx\n",
scount, superpage_start, supermfn);
+ for (k=0; k<scount; k++)
+ {
+ /* We just allocated a new mfn above; update p2m */
+ ctx->p2m[superpage_start+k] = supermfn+k;
+ ctx->nr_pfns++;
+ /* region_map[] will be set below */
+ }
+ superpage_start=INVALID_P2M_ENTRY;
+ scount=0;
+ }
+ continue;
+ }
+
+ fallback:
+ DPRINTF("Falling back %d pages pfn %lx\n", scount,
superpage_start);
+ for (k=0; k<scount; k++)
+ {
+ ctx->p2m_batch[nr_mfns++] = superpage_start+k;
+ ctx->p2m[superpage_start+k]--;
+ }
+ superpage_start = INVALID_P2M_ENTRY;
+ scount=0;
+ }
+
+ /* Are we ready to start a new superpage candidate? */
+ if ( superpages && SUPER_PAGE_START(pfn) )
+ {
+ superpage_start=pfn;
+ scount++;
+ continue;
+ }
+
+ /* Add the current pfn to pfn_batch */
ctx->p2m_batch[nr_mfns++] = pfn;
ctx->p2m[pfn]--;
}
- }
+ }
+
+ /* Clean up any partial superpage candidates */
+ if ( superpage_start != INVALID_P2M_ENTRY )
+ {
+ DPRINTF("Falling back %d pages pfn %lx\n", scount, superpage_start);
+ for (k=0; k<scount; k++)
+ {
+ ctx->p2m_batch[nr_mfns++] = superpage_start+k;
+ ctx->p2m[superpage_start+k]--;
+ }
+ superpage_start = INVALID_P2M_ENTRY;
+ }
/* Now allocate a bunch of mfns for this batch */
- if ( nr_mfns &&
- (xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0,
- 0, ctx->p2m_batch) != 0) )
- {
- ERROR("Failed to allocate memory for batch.!\n");
- errno = ENOMEM;
- return -1;
+ if ( nr_mfns )
+ {
+ DPRINTF("Mapping order 0, %d; first pfn %lx\n", nr_mfns,
ctx->p2m_batch[0]);
+
+ if(xc_domain_populate_physmap_exact(xch, dom, nr_mfns, 0,
+ 0, ctx->p2m_batch) != 0)
+ {
+ ERROR("Failed to allocate memory for batch.!\n");
+ errno = ENOMEM;
+ return -1;
+ }
}
/* Second pass for this batch: update p2m[] and region_mfn[] */
@@ -977,7 +1068,8 @@ static int apply_batch(xc_interface *xch
if (pfn_err[i])
{
- ERROR("unexpected PFN mapping failure");
+ ERROR("unexpected PFN mapping failure pfn %lx map_mfn %lx p2m_mfn
%lx",
+ pfn, region_mfn[i], ctx->p2m[pfn]);
goto err_mapped;
}
@@ -1148,9 +1240,6 @@ int xc_domain_restore(xc_interface *xch,
/* For info only */
ctx->nr_pfns = 0;
- if ( superpages )
- return 1;
-
ctxt = xc_hypercall_buffer_alloc(xch, ctxt, sizeof(*ctxt));
if ( ctxt == NULL )
@@ -1298,7 +1387,8 @@ int xc_domain_restore(xc_interface *xch,
int brc;
brc = apply_batch(xch, dom, ctx, region_mfn, pfn_type,
- pae_extended_cr3, hvm, mmu, &pagebuf, curbatch);
+ pae_extended_cr3, hvm, mmu, &pagebuf, curbatch,
+ superpages);
if ( brc < 0 )
goto out;
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