The patch titled
get_options to allow a hypenated range for isolcpus
has been added to the -mm tree. Its filename is
get_options-to-allow-a-hypenated-range-for-isolcpus.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: get_options to allow a hypenated range for isolcpus
From: Derek Fults <dfults@xxxxxxx>
This allows a hyphenated range of positive numbers in the string passed
to command line helper function, get_options.
Currently the command line option "isolcpus=" takes as its argument a
list of cpus.
Format: <cpu number>,...,<cpu number>
Valid values of <cpu_number> include all cpus, 0 to "number of CPUs in
system - 1". This can get extremely long when isolating the majority of
cpus on a large system. The kernel isolcpus code would not need any
changing to use this feature. To use it, the change would be in the
command line format for 'isolcpus='
Format:
<cpu number>,...,<cpu number>
or
<cpu number>-<cpu number> (must be a positive range in ascending
order.)
or a mixture
<cpu number>,...,<cpu number>-<cpu number>
Signed-off-by: Derek Fults <dfults@xxxxxxx>
Cc: "Randy.Dunlap" <rdunlap@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
Documentation/kernel-parameters.txt | 7 ++++-
lib/cmdline.c | 35 +++++++++++++++++++++++++-
2 files changed, 40 insertions(+), 2 deletions(-)
diff -puN Documentation/kernel-parameters.txt~get_options-to-allow-a-hypenated-range-for-isolcpus Documentation/kernel-parameters.txt
--- a/Documentation/kernel-parameters.txt~get_options-to-allow-a-hypenated-range-for-isolcpus
+++ a/Documentation/kernel-parameters.txt
@@ -712,7 +712,12 @@ and is between 256 and 4096 characters.
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
- Format: <cpu number>,...,<cpu number>
+ Format:
+ <cpu number>,...,<cpu number>
+ or
+ <cpu number>-<cpu number> (must be a positive range in ascending order)
+ or a mixture
+ <cpu number>,...,<cpu number>-<cpu number>
This option can be used to specify one or more CPUs
to isolate from the general SMP balancing and scheduling
algorithms. The only way to move a process onto or off
diff -puN lib/cmdline.c~get_options-to-allow-a-hypenated-range-for-isolcpus lib/cmdline.c
--- a/lib/cmdline.c~get_options-to-allow-a-hypenated-range-for-isolcpus
+++ a/lib/cmdline.c
@@ -16,6 +16,23 @@
#include <linux/kernel.h>
#include <linux/string.h>
+/*
+ * If a hyphen was found in get_option, this will handle the
+ * range of numbers, M-N. This will expand the range and insert
+ * the values[M, M+1, ..., N] into the ints array in get_options.
+ */
+
+static int get_range(char **str, int *pint)
+{
+ int x, inc_counter, upper_range;
+
+ (*str)++;
+ upper_range = simple_strtol((*str), NULL, 0);
+ inc_counter = upper_range - *pint;
+ for (x = *pint; x < upper_range; x++)
+ *pint++ = x;
+ return inc_counter;
+}
/**
* get_option - Parse integer from an option string
@@ -29,6 +46,7 @@
* 0 : no int in string
* 1 : int found, no subsequent comma
* 2 : int found including a subsequent comma
+ * 3 : hyphen found to denote a range
*/
int get_option (char **str, int *pint)
@@ -44,6 +62,8 @@ int get_option (char **str, int *pint)
(*str)++;
return 2;
}
+ if (**str == '-')
+ return 3;
return 1;
}
@@ -55,7 +75,8 @@ int get_option (char **str, int *pint)
* @ints: integer array
*
* This function parses a string containing a comma-separated
- * list of integers. The parse halts when the array is
+ * list of integers, a hyphen-separated range of _positive_ integers,
+ * or a combination of both. The parse halts when the array is
* full, or when no more numbers can be retrieved from the
* string.
*
@@ -72,6 +93,18 @@ char *get_options(const char *str, int n
res = get_option ((char **)&str, ints + i);
if (res == 0)
break;
+ if (res == 3) {
+ int range_nums;
+ range_nums = get_range((char **)&str, ints + i);
+ if (range_nums < 0)
+ break;
+ /*
+ * Decrement the result by one to leave out the
+ * last number in the range. The next iteration
+ * will handle the upper number in the range
+ */
+ i += (range_nums - 1);
+ }
i++;
if (res == 1)
break;
_
Patches currently in -mm which might be from dfults@xxxxxxx are
get_options-to-allow-a-hypenated-range-for-isolcpus.patch
-
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