Messages in this thread Patch in this message | | | Date | Thu, 2 Nov 2006 09:46:27 -0600 (CST) | From | Derek Fults <> | Subject | [PATCH] get_options to allow a hypenated range for isolcpus |
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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@sgi.com>
=================================================================== --- linux.orig/Documentation/kernel-parameters.txt 2006-10-27 15:02:12.338594489 -0500 +++ linux/Documentation/kernel-parameters.txt 2006-11-01 15:22:36.021698253 -0600 @@ -713,7 +713,12 @@ 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 --- linux.orig/lib/cmdline.c 2006-11-02 07:51:05.247994341 -0600 +++ linux/lib/cmdline.c 2006-11-01 14:21:38.579984694 -0600 @@ -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 @@ (*str)++; return 2; } + if (**str == '-') + return 3;
return 1; } @@ -55,7 +75,8 @@ * @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 @@ 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; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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