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From: Costin Lupu <costin.lupu@cs.pub.ro>
To: xen-devel@lists.xenproject.org
Cc: Ian Jackson <iwj@xenproject.org>, Wei Liu <wl@xen.org>,
	Anthony PERARD <anthony.perard@citrix.com>
Subject: [PATCH] tools/libs/light: Remove unnecessary libxl_list_vm() call
Date: Mon, 19 Apr 2021 16:01:42 +0300	[thread overview]
Message-ID: <cf7c0f8869a087008fbe10888ebf96336b1ccb7b.1618837159.git.costin.lupu@cs.pub.ro> (raw)

The removed lines were initially added by commit 314e64084d31, but the
subsequent code which was using the nb_vm variable was later removed by
commit 2ba368d13893, which makes these lines of code an overlooked
reminiscence. Moreover, the call becomes very expensive when there is a
considerable number of VMs (~1000 instances) running on the host.

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
 tools/libs/light/libxl_create.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/tools/libs/light/libxl_create.c b/tools/libs/light/libxl_create.c
index 0c64268f66..43e9ba9c63 100644
--- a/tools/libs/light/libxl_create.c
+++ b/tools/libs/light/libxl_create.c
@@ -578,7 +578,7 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config *d_config,
                        uint32_t *domid, bool soft_reset)
     libxl_ctx *ctx = libxl__gc_owner(gc);
-    int ret, rc, nb_vm;
+    int ret, rc;
     const char *dom_type;
     char *uuid_string;
     char *dom_path, *vm_path, *libxl_path;
@@ -586,7 +586,6 @@ int libxl__domain_make(libxl__gc *gc, libxl_domain_config *d_config,
     struct xs_permissions rwperm[1];
     struct xs_permissions noperm[1];
     xs_transaction_t t = 0;
-    libxl_vminfo *vm_list;
     /* convenience aliases */
     libxl_domain_create_info *info = &d_config->c_info;
@@ -869,14 +868,6 @@ retry_transaction:
-    vm_list = libxl_list_vm(ctx, &nb_vm);
-    if (!vm_list) {
-        LOGD(ERROR, *domid, "cannot get number of running guests");
-        rc = ERROR_FAIL;
-        goto out;
-    }
-    libxl_vminfo_list_free(vm_list, nb_vm);
     xs_write(ctx->xsh, t, GCSPRINTF("%s/uuid", vm_path), uuid_string, strlen(uuid_string));
     xs_write(ctx->xsh, t, GCSPRINTF("%s/name", vm_path), info->name, strlen(info->name));

             reply	other threads:[~2021-04-19 13:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-19 13:01 Costin Lupu [this message]
2021-04-21 10:08 ` [PATCH] tools/libs/light: Remove unnecessary libxl_list_vm() call Wei Liu

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