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[Xen-devel] Re: [PATCH] libxenlight: implement libxl_set_memory_target

To: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Subject: [Xen-devel] Re: [PATCH] libxenlight: implement libxl_set_memory_target
From: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
Date: Wed, 09 Dec 2009 15:47:17 -0500
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Vincent Hanquez <Vincent.Hanquez@xxxxxxxxxxxxx>
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Stefano Stabellini wrote:
On Tue, 8 Dec 2009, Andres Lagar-Cavilla wrote:
couple of comments:
- PV domains without videoram won't be able to use this

PV domains just have videoram = 0.
But you abort libxl_set_memory_target if the videoram node is not found. Which won't be for PVs with no videoram... + videoram_s = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/videoram", dompath));
+    if (!videoram_s)
+        return -1;

- Further, doesn't the PV domain build function need to use target_memkb? (That's my read of what xend does at least)

Yes, you are right, I'll fix this.

- Finally, LIBXL_MAXMEM_CONSTANT looks like an "evil constant we should avoid". Where did it come from?

I decided to introduce this constant after a discussion with developers
of the memory management functions in xapi: after thorough testing they
found that adding 1 MB to maxmem increases the robustness of the system.

BTW the current value of the constant is wrong because it should be
expressed in KB, I'll send a patch to fix this later today.

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