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Re: [Xen-devel] [PATCH v5 RFC 13/14] tools/libxc: noarch save code
On 06/12/2014 02:14 AM, Andrew Cooper wrote:
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Signed-off-by: Frediano Ziglio <frediano.ziglio@xxxxxxxxxx>
Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
tools/libxc/saverestore/save.c | 545 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 544 insertions(+), 1 deletion(-)
diff --git a/tools/libxc/saverestore/save.c b/tools/libxc/saverestore/save.c
index f6ad734..9ad43a5 100644
--- a/tools/libxc/saverestore/save.c
+++ b/tools/libxc/saverestore/save.c
@@ -1,11 +1,554 @@
+#include <assert.h>
+#include <arpa/inet.h>
+
#include "common.h"
+/*
+ * Writes an Image header and Domain header into the stream.
+ */
+static int write_headers(struct context *ctx, uint16_t guest_type)
+{
+ xc_interface *xch = ctx->xch;
...snip...
+/*
+ * Send all domain memory. This is the heart of the live migration loop.
+ */
+static int send_domain_memory(struct context *ctx)
+{
+ xc_interface *xch = ctx->xch;
+ DECLARE_HYPERCALL_BUFFER(unsigned long, to_send);
+ xc_shadow_op_stats_t stats = { -1, -1 };
+ unsigned pages_written;
+ unsigned x, max_iter = 5, dirty_threshold = 50;
+ xen_pfn_t p;
+ int rc = -1;
+
+ to_send = xc_hypercall_buffer_alloc_pages(
+ xch, to_send, NRPAGES(bitmap_size(ctx->save.p2m_size)));
+
+ ctx->save.batch_pfns = malloc(MAX_BATCH_SIZE *
sizeof(*ctx->save.batch_pfns));
+ ctx->save.deferred_pages = calloc(1, bitmap_size(ctx->save.p2m_size));
+
+ if ( !ctx->save.batch_pfns || !to_send || !ctx->save.deferred_pages )
+ {
+ ERROR("Unable to allocate memory for to_{send,fix}/batch bitmaps");
+ goto out;
+ }
+
+ if ( xc_shadow_control(xch, ctx->domid,
+ XEN_DOMCTL_SHADOW_OP_ENABLE_LOGDIRTY,
+ NULL, 0, NULL, 0, NULL) < 0 )
+ {
+ PERROR("Failed to enable logdirty");
+ goto out;
+ }
+
+ for ( x = 0, pages_written = 0; x < max_iter ; ++x )
+ {
+ if ( x == 0 )
+ {
+ /* First iteration, send all pages. */
+ memset(to_send, 0xff, bitmap_size(ctx->save.p2m_size));
+ }
+ else
+ {
+ /* Else consult the dirty bitmap. */
+ if ( xc_shadow_control(
+ xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_CLEAN,
+ HYPERCALL_BUFFER(to_send), ctx->save.p2m_size,
+ NULL, 0, &stats) != ctx->save.p2m_size )
+ {
+ PERROR("Failed to retrieve logdirty bitmap");
+ rc = -1;
+ goto out;
+ }
+ else
+ DPRINTF(" Wrote %u pages; stats: faults %"PRIu32", dirty
%"PRIu32,
+ pages_written, stats.fault_count, stats.dirty_count);
+ pages_written = 0;
+
+ if ( stats.dirty_count < dirty_threshold )
+ break;
+ }
+
+ DPRINTF("Iteration %u", x);
+
+ for ( p = 0 ; p < ctx->save.p2m_size; ++p )
+ {
+ if ( test_bit(p, to_send) )
+ {
+ rc = add_to_batch(ctx, p);
+ if ( rc )
+ goto out;
+ ++pages_written;
+ }
+ }
+
+ rc = flush_batch(ctx);
+ if ( rc )
+ goto out;
+ }
+
+ rc = pause_domain(ctx);
+ if ( rc )
+ goto out;
+
+ if ( xc_shadow_control(
+ xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_CLEAN,
+ HYPERCALL_BUFFER(to_send), ctx->save.p2m_size,
+ NULL, 0, &stats) != ctx->save.p2m_size )
+ {
+ PERROR("Failed to retrieve logdirty bitmap");
+ rc = -1;
+ goto out;
+ }
+
+ for ( p = 0, pages_written = 0 ; p < ctx->save.p2m_size; ++p )
+ {
+ if ( test_bit(p, to_send) || test_bit(p, ctx->save.deferred_pages) )
+ {
+ rc = add_to_batch(ctx, p);
+ if ( rc )
+ goto out;
+ ++pages_written;
+ }
+ }
+
+ rc = flush_batch(ctx);
+ if ( rc )
+ goto out;
+
+ DPRINTF(" Wrote %u pages", pages_written);
+ IPRINTF("Sent all pages");
+
+ out:
+ xc_hypercall_buffer_free_pages(xch, to_send,
+ NRPAGES(bitmap_size(ctx->save.p2m_size)));
+ free(ctx->save.deferred_pages);
+ free(ctx->save.batch_pfns);
+ return rc;
+}
+
+/*
+ * Save a domain.
+ */
+static int save(struct 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",
+ ctx->domid, dhdr_type_to_str(guest_type));
+
+ rc = ctx->save.ops.setup(ctx);
+ if ( rc )
+ goto err;
+
+ rc = write_headers(ctx, guest_type);
+ if ( rc )
+ goto err;
+
+ rc = ctx->save.ops.start_of_stream(ctx);
+ if ( rc )
+ goto err;
+
+ rc = send_domain_memory(ctx);
+ if ( rc )
+ goto err;
+
+ /* Refresh domain information now it has paused. */
+ if ( (xc_domain_getinfo(xch, ctx->domid, 1, &ctx->dominfo) != 1) ||
+ (ctx->dominfo.domid != ctx->domid) )
+ {
+ PERROR("Unable to refresh domain information");
+ rc = -1;
+ goto err;
+ }
+ else if ( (!ctx->dominfo.shutdown ||
+ ctx->dominfo.shutdown_reason != SHUTDOWN_suspend ) &&
+ !ctx->dominfo.paused )
+ {
+ ERROR("Domain has not been suspended");
+ rc = -1;
+ goto err;
+ }
+
+ rc = ctx->save.ops.end_of_stream(ctx);
+ if ( rc )
+ goto err;
+
+ rc = write_end_record(ctx);
+ if ( rc )
+ goto err;
+
+ xc_shadow_control(xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_OFF,
+ NULL, 0, NULL, 0, NULL);
If migration failed because log-dirty already been enabled or there's err after
we enabled log-dirty, we should off shadow op. otherwise we will always fail
when migration, so this op should under error path. The following patch fix it.
diff --git a/tools/libxc/saverestore/save.c b/tools/libxc/saverestore/save.c
index 9ad43a5..6e9d325 100644
--- a/tools/libxc/saverestore/save.c
+++ b/tools/libxc/saverestore/save.c
@@ -474,9 +474,6 @@ static int save(struct context *ctx, uint16_t guest_type)
if ( rc )
goto err;
- xc_shadow_control(xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_OFF,
- NULL, 0, NULL, 0, NULL);
-
IPRINTF("Save successful");
goto done;
@@ -490,6 +487,9 @@ static int save(struct context *ctx, uint16_t guest_type)
if ( rc )
PERROR("Failed to clean up");
+ xc_shadow_control(xch, ctx->domid, XEN_DOMCTL_SHADOW_OP_OFF,
+ NULL, 0, NULL, 0, NULL);
+
if ( saved_rc )
{
rc = saved_rc;
+
+ IPRINTF("Save successful");
+ goto done;
+
+ err:
+ saved_errno = errno;
+ saved_rc = rc;
+ PERROR("Save failed");
+
+ done:
+ rc = ctx->save.ops.cleanup(ctx);
+ if ( rc )
+ PERROR("Failed to clean up");
+
+ if ( saved_rc )
+ {
+ rc = saved_rc;
+ errno = saved_errno;
+ }
+
+ return rc;
+};
+
int xc_domain_save2(xc_interface *xch, int io_fd, uint32_t dom, uint32_t
max_iters,
uint32_t max_factor, uint32_t flags,
struct save_callbacks* callbacks, int hvm)
{
+ struct context ctx =
+ {
+ .xch = xch,
+ .fd = io_fd,
+ };
+
+ /* GCC 4.4 (of CentOS 6.x vintage) can' t initialise anonymous unions :( */
+ ctx.save.callbacks = callbacks;
+
IPRINTF("In experimental %s", __func__);
- return -1;
+
+ if ( xc_domain_getinfo(xch, dom, 1, &ctx.dominfo) != 1 )
+ {
+ PERROR("Failed to get domain info");
+ return -1;
+ }
+
+ if ( ctx.dominfo.domid != dom )
+ {
+ ERROR("Domain %d does not exist", dom);
+ return -1;
+ }
+
+ ctx.domid = dom;
+ IPRINTF("Saving domain %d", dom);
+
+ ctx.save.p2m_size = xc_domain_maximum_gpfn(xch, dom) + 1;
+ if ( ctx.save.p2m_size > ~XEN_DOMCTL_PFINFO_LTAB_MASK )
+ {
+ errno = E2BIG;
+ ERROR("Cannot save this big a guest");
+ return -1;
+ }
+
+ if ( ctx.dominfo.hvm )
+ {
+ ctx.ops = common_ops_x86_hvm;
+ ctx.save.ops = save_ops_x86_hvm;
+ return save(&ctx, DHDR_TYPE_X86_HVM);
+ }
+ else
+ {
+ ctx.ops = common_ops_x86_pv;
+ ctx.save.ops = save_ops_x86_pv;
+ return save(&ctx, DHDR_TYPE_X86_PV);
+ }
}
/*
--
Thanks,
Yang.
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