ignored. This parameter may be specified with a B, K, M or G suffix,
representing bytes, kilobytes, megabytes and gigabytes respectively.
The default unit, if no suffix is specified, is kilobytes.
-\item [ dom0\_mem=xxx ] Set the amount of memory to be allocated to
- domain0. In Xen 3.x the parameter may be specified with a B, K, M or
+\item [ dom0\_mem=$<$specifier list$>$ ] Set the amount of memory to
+ be allocated to domain 0. This is a comma-separated list containing
+ the following optional components:
+ \begin{description}
+ \item[ min:$<$min\_amt$>$ ] Minimum amount to allocate to domain 0
+ \item[ max:$<$min\_amt$>$ ] Maximum amount to allocate to domain 0
+ \item[ $<$amt$>$ ] Precise amount to allocate to domain 0
+ \end{description}
+ Each numeric parameter may be specified with a B, K, M or
G suffix, representing bytes, kilobytes, megabytes and gigabytes
respectively; if no suffix is specified, the parameter defaults to
- kilobytes. In previous versions of Xen, suffixes were not supported
- and the value is always interpreted as kilobytes.
+ kilobytes. Negative values are subtracted from total available
+ memory. If $<$amt$>$ is not specified, it defaults to all available
+ memory less a small amount (clamped to 128MB) for uses such as DMA
+ buffers.
\item [ dom0\_vcpus\_pin ] Pins domain 0 VCPUs on their respective
physical CPUS (default=false).
\item [ tbuf\_size=xxx ] Set the size of the per-cpu trace buffers, in
extern unsigned long initial_images_nrpages(void);
extern void discard_initial_images(void);
-static long dom0_nrpages;
+static long dom0_nrpages, dom0_min_nrpages, dom0_max_nrpages = LONG_MAX;
/*
- * dom0_mem:
- * If +ve:
- * * The specified amount of memory is allocated to domain 0.
- * If -ve:
- * * All of memory is allocated to domain 0, minus the specified amount.
- * If not specified:
- * * All of memory is allocated to domain 0, minus 1/16th which is reserved
- * for uses such as DMA buffers (the reservation is clamped to 128MB).
+ * dom0_mem=[min:<min_amt>,][max:<max_amt>,][<amt>]
+ *
+ * <min_amt>: The minimum amount of memory which should be allocated for dom0.
+ * <max_amt>: The maximum amount of memory which should be allocated for dom0.
+ * <amt>: The precise amount of memory to allocate for dom0.
+ *
+ * Notes:
+ * 1. <amt> is clamped from below by <min_amt> and from above by available
+ * memory and <max_amt>
+ * 2. <min_amt> is clamped from above by available memory and <max_amt>
+ * 3. <min_amt> is ignored if it is greater than <max_amt>
+ * 4. If <amt> is not specified, it is calculated as follows:
+ * "All of memory is allocated to domain 0, minus 1/16th which is reserved
+ * for uses such as DMA buffers (the reservation is clamped to 128MB)."
+ *
+ * Each value can be specified as positive or negative:
+ * If +ve: The specified amount is an absolute value.
+ * If -ve: The specified amount is subtracted from total available memory.
*/
+static long parse_amt(char *s, char **ps)
+{
+ long pages = parse_size_and_unit((*s == '-') ? s+1 : s, ps) >> PAGE_SHIFT;
+ return (*s == '-') ? -pages : pages;
+}
static void parse_dom0_mem(char *s)
{
- unsigned long long bytes;
- char *t = s;
- if ( *s == '-' )
- t++;
- bytes = parse_size_and_unit(t);
- dom0_nrpages = bytes >> PAGE_SHIFT;
- if ( *s == '-' )
- dom0_nrpages = -dom0_nrpages;
+ do {
+ if ( !strncmp(s, "min:", 4) )
+ dom0_min_nrpages = parse_amt(s+4, &s);
+ else if ( !strncmp(s, "max:", 4) )
+ dom0_max_nrpages = parse_amt(s+4, &s);
+ else
+ dom0_nrpages = parse_amt(s, &s);
+ if ( *s != ',' )
+ break;
+ } while ( *s++ == ',' );
}
custom_param("dom0_mem", parse_dom0_mem);
return page;
}
+static unsigned long compute_dom0_nr_pages(void)
+{
+ unsigned long avail = avail_domheap_pages() + initial_images_nrpages();
+
+ /*
+ * If domain 0 allocation isn't specified, reserve 1/16th of available
+ * memory for things like DMA buffers. This reservation is clamped to
+ * a maximum of 128MB.
+ */
+ if ( dom0_nrpages == 0 )
+ {
+ dom0_nrpages = avail;
+ dom0_nrpages = min(dom0_nrpages / 16, 128L << (20 - PAGE_SHIFT));
+ dom0_nrpages = -dom0_nrpages;
+ }
+
+ /* Negative memory specification means "all memory - specified amount". */
+ if ( dom0_nrpages < 0 ) dom0_nrpages += avail;
+ if ( dom0_min_nrpages < 0 ) dom0_min_nrpages += avail;
+ if ( dom0_max_nrpages < 0 ) dom0_max_nrpages += avail;
+
+ /* Clamp dom0 memory according to min/max limits and available memory. */
+ dom0_nrpages = max(dom0_nrpages, dom0_min_nrpages);
+ dom0_nrpages = min(dom0_nrpages, dom0_max_nrpages);
+ dom0_nrpages = min(dom0_nrpages, (long)avail);
+
+ return dom0_nrpages;
+}
+
static void process_dom0_ioports_disable(void)
{
unsigned long io_from, io_to;
d->max_pages = ~0U;
- /*
- * If domain 0 allocation isn't specified, reserve 1/16th of available
- * memory for things like DMA buffers. This reservation is clamped to
- * a maximum of 128MB.
- */
- if ( dom0_nrpages == 0 )
- {
- dom0_nrpages = avail_domheap_pages() + initial_images_nrpages();
- dom0_nrpages = min(dom0_nrpages / 16, 128L << (20 - PAGE_SHIFT));
- dom0_nrpages = -dom0_nrpages;
- }
-
- /* Negative memory specification means "all memory - specified amount". */
- if ( dom0_nrpages < 0 )
- nr_pages = avail_domheap_pages() + initial_images_nrpages() +
- dom0_nrpages;
- else
- nr_pages = min(avail_domheap_pages() + initial_images_nrpages(),
- (unsigned long)dom0_nrpages);
+ nr_pages = compute_dom0_nr_pages();
if ( (rc = parseelfimage(&dsi)) != 0 )
return rc;
projects / xen.git / commitdiff