Re: [Xen-devel] [PATCH] libxl: add a dummy ao_how to libxl_domain_core_dump

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2012-04-16 at 17:31 +0100, Ian Jackson wrote:
> Ian Campbell writes ("Re: [PATCH] libxl: add a dummy ao_how to 
> libxl_domain_core_dump"):
> > On Mon, 2012-04-16 at 16:50 +0100, Ian Jackson wrote:
> > > Ian Campbell writes ("[PATCH] libxl: add a dummy ao_how to 
> > > libxl_domain_core_dump"):
> > > > libxl: add a dummy ao_how to libxl_domain_core_dump
> > > > -        return ERROR_FAIL;
> > > > +        rc = ERROR_FAIL;
> > > 
> > > While you're doing that, did you want to change it to use "goto out" ?
> > 
> > wouldn't the "out:" be immediately after this immediately following
> > closing brace?
> 
> I think it would look like this:

Make sense.

8<--------------------------------

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1334595420 -3600
# Node ID 8d92d1f34921c8675d85c74aa36e319c9451f68f
# Parent  f95c8fe372d35fdf8937750e9271ea76ff991488
libxl: add a dummy ao_how to libxl_domain_core_dump

Although this function is not currently slow it may become so in the future
(this also depends somewhat on the size of the guest).  Therefore arrange for
it to take an ao_how which it completes immediately.  This will allow us to
make it asynchronous in the future without breaking API compatibility.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---

Requires Ian Jackson's "libxl: Allow AO_GC and EGC_GC even if not used"

diff -r f95c8fe372d3 -r 8d92d1f34921 tools/libxl/libxl.c
--- a/tools/libxl/libxl.c       Fri Apr 13 19:40:07 2012 +0100
+++ b/tools/libxl/libxl.c       Mon Apr 16 17:57:00 2012 +0100
@@ -627,16 +627,26 @@ int libxl_domain_pause(libxl_ctx *ctx, u
 }
 
 int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid,
-                           const char *filename)
+                           const char *filename,
+                           const libxl_asyncop_how *ao_how)
 {
-    int ret;
+    AO_CREATE(ctx, domid, ao_how);
+    int ret, rc;
+
     ret = xc_domain_dumpcore(ctx->xch, domid, filename);
     if (ret<0) {
         LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "core dumping domain %d to %s",
                      domid, filename);
-        return ERROR_FAIL;
+        rc = ERROR_FAIL;
+        goto out;
     }
-    return 0;
+
+    rc = 0;
+out:
+
+    libxl__ao_complete(egc, ao, rc);
+
+    return AO_INPROGRESS;
 }
 
 int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
diff -r f95c8fe372d3 -r 8d92d1f34921 tools/libxl/libxl.h
--- a/tools/libxl/libxl.h       Fri Apr 13 19:40:07 2012 +0100
+++ b/tools/libxl/libxl.h       Mon Apr 16 17:57:00 2012 +0100
@@ -509,7 +509,9 @@ int libxl_domain_rename(libxl_ctx *ctx, 
 int libxl_domain_pause(libxl_ctx *ctx, uint32_t domid);
 int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid);
 
-int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid, const char 
*filename);
+int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid,
+                           const char *filename,
+                           const libxl_asyncop_how *ao_how);
 
 int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint32_t 
target_memkb);
 int libxl_set_memory_target(libxl_ctx *ctx, uint32_t domid, int32_t 
target_memkb, int relative, int enforce);
diff -r f95c8fe372d3 -r 8d92d1f34921 tools/libxl/xl_cmdimpl.c
--- a/tools/libxl/xl_cmdimpl.c  Fri Apr 13 19:40:07 2012 +0100
+++ b/tools/libxl/xl_cmdimpl.c  Mon Apr 16 17:57:00 2012 +0100
@@ -1276,7 +1276,7 @@ static int handle_domain_death(libxl_ctx
             LOG("failed to construct core dump path");
         } else {
             LOG("dumping core to %s", corefile);
-            rc=libxl_domain_core_dump(ctx, domid, corefile);
+            rc=libxl_domain_core_dump(ctx, domid, corefile, NULL);
             if (rc) LOG("core dump failed (rc=%d).", rc);
         }
         /* No point crying over spilled milk, continue on failure. */
@@ -2893,7 +2893,7 @@ static void core_dump_domain(const char 
 {
     int rc;
     find_domain(domain_spec);
-    rc=libxl_domain_core_dump(ctx, domid, filename);
+    rc=libxl_domain_core_dump(ctx, domid, filename, NULL);
     if (rc) { fprintf(stderr,"core dump failed (rc=%d)\n",rc);exit(-1); }
 }
 



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