53 lines
2.2 KiB
Diff
53 lines
2.2 KiB
Diff
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commit f7143d2f0d918cf96010f1d7610b3c3bf7005c1d
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Author: Jim Fehlig <jfehlig@suse.com>
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Date: Tue Jan 17 15:11:32 2017 -0700
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libxl: fix dom0 autoballooning with Xen 4.8
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xen.git commit 57f8b13c changed several of the libxl memory
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get/set functions to take 64 bit parameters. The libvirt
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libxl driver still uses uint32_t variables for these various
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parameters, which is particularly problematic for the
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libxl_set_memory_target() function.
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When dom0 autoballooning is enabled, libvirt (like xl) determines
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the memory needed to start a domain and the memory available. If
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memory available is less than memory needed, dom0 is ballooned
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down by passing a negative value to libxl_set_memory_target()
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'target_memkb' parameter. Prior to xen.git commit 57f8b13c,
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'target_memkb' was an int32_t. Subtracting a larger uint32 from
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a smaller uint32 and assigning it to int32 resulted in a negative
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number. After commit 57f8b13c, the same subtraction is widened
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to a int64, resulting in a large positive number. The simple
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fix taken by this patch is to assign the difference of the
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uint32 values to a temporary int32 variable, which is then
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passed to 'target_memkb' parameter of libxl_set_memory_target().
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Note that it is undesirable to change libvirt to use 64 bit
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variables since it requires setting LIBXL_API_VERSION to 0x040800.
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Currently libvirt supports LIBXL_API_VERSION >= 0x040400,
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essentially Xen >= 4.4.
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Index: libvirt-3.0.0/src/libxl/libxl_domain.c
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===================================================================
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--- libvirt-3.0.0.orig/src/libxl/libxl_domain.c
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+++ libvirt-3.0.0/src/libxl/libxl_domain.c
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@@ -909,6 +909,7 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl
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{
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uint32_t needed_mem;
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uint32_t free_mem;
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+ int32_t target_mem;
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int tries = 3;
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int wait_secs = 10;
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@@ -922,7 +923,8 @@ libxlDomainFreeMem(libxl_ctx *ctx, libxl
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if (free_mem >= needed_mem)
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return 0;
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- if (libxl_set_memory_target(ctx, 0, free_mem - needed_mem,
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+ target_mem = free_mem - needed_mem;
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+ if (libxl_set_memory_target(ctx, 0, target_mem,
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/* relative */ 1, 0) < 0)
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goto error;
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