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Re: [Xen-devel] [PATCH v5 RFC 13/14] tools/libxc: noarch save code
On 06/18/2014 02:59 PM, Hongyang Yang wrote:
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.
Or there's another solution, just like the old migration, try to re-enable log
dirty if enable log dirty failed.
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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