[PATCH] get_options to allow a hypenated range for isolcpus
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> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -714,7 +714,12 @@ and is between 256 and 4096 characters. It is defined in the file
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Format: <RDP>,<reset>,<pci_scan>,<verbosity>
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Format: <RDP>,<reset>,<pci_scan>,<verbosity>
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isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
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isolcpus= [KNL,SMP] Isolate CPUs from the general scheduler.
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Format: <cpu number>,...,<cpu number>
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Format:
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<cpu number>,...,<cpu number>
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or
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<cpu number>-<cpu number> (must be a positive range in ascending order)
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or a mixture
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<cpu number>,...,<cpu number>-<cpu number>
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This option can be used to specify one or more CPUs
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This option can be used to specify one or more CPUs
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to isolate from the general SMP balancing and scheduling
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to isolate from the general SMP balancing and scheduling
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algorithms. The only way to move a process onto or off
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algorithms. The only way to move a process onto or off
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@ -16,6 +16,23 @@
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#include <linux/kernel.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/string.h>
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/*
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* If a hyphen was found in get_option, this will handle the
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* range of numbers, M-N. This will expand the range and insert
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* the values[M, M+1, ..., N] into the ints array in get_options.
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*/
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static int get_range(char **str, int *pint)
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{
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int x, inc_counter, upper_range;
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(*str)++;
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upper_range = simple_strtol((*str), NULL, 0);
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inc_counter = upper_range - *pint;
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for (x = *pint; x < upper_range; x++)
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*pint++ = x;
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return inc_counter;
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}
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/**
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/**
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* get_option - Parse integer from an option string
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* get_option - Parse integer from an option string
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@ -29,6 +46,7 @@
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* 0 : no int in string
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* 0 : no int in string
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* 1 : int found, no subsequent comma
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* 1 : int found, no subsequent comma
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* 2 : int found including a subsequent comma
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* 2 : int found including a subsequent comma
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* 3 : hyphen found to denote a range
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*/
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*/
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int get_option (char **str, int *pint)
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int get_option (char **str, int *pint)
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@ -44,6 +62,8 @@ int get_option (char **str, int *pint)
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(*str)++;
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(*str)++;
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return 2;
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return 2;
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}
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}
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if (**str == '-')
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return 3;
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return 1;
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return 1;
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}
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}
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@ -55,7 +75,8 @@ int get_option (char **str, int *pint)
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* @ints: integer array
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* @ints: integer array
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*
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*
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* This function parses a string containing a comma-separated
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* This function parses a string containing a comma-separated
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* list of integers. The parse halts when the array is
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* list of integers, a hyphen-separated range of _positive_ integers,
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* or a combination of both. The parse halts when the array is
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* full, or when no more numbers can be retrieved from the
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* full, or when no more numbers can be retrieved from the
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* string.
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* string.
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*
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*
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@ -72,6 +93,18 @@ char *get_options(const char *str, int nints, int *ints)
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res = get_option ((char **)&str, ints + i);
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res = get_option ((char **)&str, ints + i);
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if (res == 0)
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if (res == 0)
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break;
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break;
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if (res == 3) {
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int range_nums;
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range_nums = get_range((char **)&str, ints + i);
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if (range_nums < 0)
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break;
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/*
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* Decrement the result by one to leave out the
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* last number in the range. The next iteration
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* will handle the upper number in the range
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*/
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i += (range_nums - 1);
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}
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i++;
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i++;
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if (res == 1)
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if (res == 1)
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break;
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break;
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