[Xen-changelog] [xen master] Revert "libxl_set_memory_target: retain the same maxmem offset on top of the current target"

[patchbot@xxxxxxx]

commit 3821d303f5d2d35f8625391879f9ada16f53a40b
Author:     Wei Liu <wei.liu2@xxxxxxxxxx>
AuthorDate: Tue Jun 23 17:07:57 2015 +0100
Commit:     Ian Campbell <ian.campbell@xxxxxxxxxx>
CommitDate: Thu Jun 25 11:22:04 2015 +0100

    Revert "libxl_set_memory_target: retain the same maxmem offset on top of 
the current target"
    
    This reverts commit 0c029c4da2169159064568ef4fea862a5d2cd84a.
    
    A new memory model that allows QEMU to bump memory behind libxl's back
    was merged a few months ago. We didn't fully understand the
    repercussions back then. Now it breaks migration and becomes blocker of
    4.6 release.
    
    It's better to restore to original behaviour at this stage of the
    release cycle, that would put us in a position no worse than before, so
    the release is unblocked.
    
    The said function is still racy after reverting these two patches.
    Making domain memory state consistent requires a bit more work. Separate
    patch(es) will be sent out to deal with that problem.
    
    Fix up conflicts with f5b43e95 (libxl: fix "xl mem-set" regression from
    0c029c4da2).
    
    Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
    Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 tools/libxl/libxl.c |   24 ++++++++++++++----------
 1 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index d86ea62..cfc2623 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -4742,16 +4742,11 @@ int libxl_set_memory_target(libxl_ctx *ctx, uint32_t 
domid,
     uint32_t current_max_memkb = 0;
     char *memmax, *endptr, *videoram_s = NULL, *target = NULL;
     char *dompath = libxl__xs_get_dompath(gc, domid);
+    xc_domaininfo_t info;
     libxl_dominfo ptr;
     char *uuid;
     xs_transaction_t t;
 
-    libxl_dominfo_init(&ptr);
-    if (libxl_domain_info(ctx, &ptr, domid) < 0)
-        goto out_no_transaction;
-
-    uuid = libxl__uuid2string(gc, ptr.uuid);
-
 retry_transaction:
     t = xs_transaction_start(ctx->xsh);
 
@@ -4827,12 +4822,13 @@ retry_transaction:
     }
 
     if (enforce) {
-        memorykb = ptr.max_memkb - current_target_memkb + new_target_memkb;
-        rc = xc_domain_setmaxmem(ctx->xch, domid, memorykb);
+        memorykb = new_target_memkb + videoram;
+        rc = xc_domain_setmaxmem(ctx->xch, domid, memorykb +
+                LIBXL_MAXMEM_CONSTANT);
         if (rc != 0) {
             LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
                     "xc_domain_setmaxmem domid=%u memkb=%"PRIu64" failed "
-                    "rc=%d\n", domid, memorykb, rc);
+                    "rc=%d\n", domid, memorykb + LIBXL_MAXMEM_CONSTANT, rc);
             abort_transaction = 1;
             goto out;
         }
@@ -4851,9 +4847,18 @@ retry_transaction:
 
     libxl__xs_write(gc, t, libxl__sprintf(gc, "%s/memory/target",
                 dompath), "%"PRIu32, new_target_memkb);
+    rc = xc_domain_getinfolist(ctx->xch, domid, 1, &info);
+    if (rc != 1 || info.domain != domid) {
+        abort_transaction = 1;
+        goto out;
+    }
 
+    libxl_dominfo_init(&ptr);
+    xcinfo2xlinfo(ctx, &info, &ptr);
+    uuid = libxl__uuid2string(gc, ptr.uuid);
     libxl__xs_write(gc, t, libxl__sprintf(gc, "/vm/%s/memory", uuid),
             "%"PRIu32, new_target_memkb / 1024);
+    libxl_dominfo_dispose(&ptr);
 
 out:
     if (!xs_transaction_end(ctx->xsh, t, abort_transaction)
@@ -4862,7 +4867,6 @@ out:
             goto retry_transaction;
 
 out_no_transaction:
-    libxl_dominfo_dispose(&ptr);
     GC_FREE;
     return rc;
 }
--
generated by git-patchbot for /home/xen/git/xen.git#master

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