From dfe564045c653d9e6969ccca57a8a04771d333f7 Mon Sep 17 00:00:00 2001 From: chao Date: Sun, 30 Aug 2020 23:41:17 -0700 Subject: rcu: Panic after fixed number of stalls Some stalls are transient, so that system fully recovers. This commit therefore allows users to configure the number of stalls that must happen in order to trigger kernel panic. Signed-off-by: chao Signed-off-by: Paul E. McKenney --- include/linux/kernel.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2f05e9128201..4b5fd3da5fe8 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -536,6 +536,7 @@ extern int panic_on_warn; extern unsigned long panic_on_taint; extern bool panic_on_taint_nousertaint; extern int sysctl_panic_on_rcu_stall; +extern int sysctl_max_rcu_stall_to_panic; extern int sysctl_panic_on_stackoverflow; extern bool crash_kexec_post_notifiers; -- cgit From 74d862b682f51e45d25b95b1ecf212428a4967b0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 18 Nov 2020 20:48:42 +0100 Subject: sched: Make migrate_disable/enable() independent of RT Now that the scheduler can deal with migrate disable properly, there is no real compelling reason to make it only available for RT. There are quite some code pathes which needlessly disable preemption in order to prevent migration and some constructs like kmap_atomic() enforce it implicitly. Making it available independent of RT allows to provide a preemptible variant of kmap_atomic() and makes the code more consistent in general. Signed-off-by: Thomas Gleixner Grudgingly-Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20201118204007.269943012@linutronix.de --- include/linux/kernel.h | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2f05e9128201..665837f9a831 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -204,6 +204,7 @@ extern int _cond_resched(void); extern void ___might_sleep(const char *file, int line, int preempt_offset); extern void __might_sleep(const char *file, int line, int preempt_offset); extern void __cant_sleep(const char *file, int line, int preempt_offset); +extern void __cant_migrate(const char *file, int line); /** * might_sleep - annotation for functions that can sleep @@ -227,6 +228,18 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); # define cant_sleep() \ do { __cant_sleep(__FILE__, __LINE__, 0); } while (0) # define sched_annotate_sleep() (current->task_state_change = 0) + +/** + * cant_migrate - annotation for functions that cannot migrate + * + * Will print a stack trace if executed in code which is migratable + */ +# define cant_migrate() \ + do { \ + if (IS_ENABLED(CONFIG_SMP)) \ + __cant_migrate(__FILE__, __LINE__); \ + } while (0) + /** * non_block_start - annotate the start of section where sleeping is prohibited * @@ -251,6 +264,7 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); int preempt_offset) { } # define might_sleep() do { might_resched(); } while (0) # define cant_sleep() do { } while (0) +# define cant_migrate() do { } while (0) # define sched_annotate_sleep() do { } while (0) # define non_block_start() do { } while (0) # define non_block_end() do { } while (0) @@ -258,13 +272,6 @@ extern void __cant_sleep(const char *file, int line, int preempt_offset); #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) -#ifndef CONFIG_PREEMPT_RT -# define cant_migrate() cant_sleep() -#else - /* Placeholder for now */ -# define cant_migrate() do { } while (0) -#endif - /** * abs - return absolute value of an argument * @x: the value. If it is unsigned type, it is converted to signed type first. -- cgit From aa6159ab99a9ab5df835b4750b66cf132a5aa292 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 15 Dec 2020 20:42:48 -0800 Subject: kernel.h: split out mathematical helpers kernel.h is being used as a dump for all kinds of stuff for a long time. Here is the attempt to start cleaning it up by splitting out mathematical helpers. At the same time convert users in header and lib folder to use new header. Though for time being include new header back to kernel.h to avoid twisted indirected includes for existing users. [sfr@canb.auug.org.au: fix powerpc build] Link: https://lkml.kernel.org/r/20201029150809.13059608@canb.auug.org.au Link: https://lkml.kernel.org/r/20201028173212.41768-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Cc: "Paul E. McKenney" Cc: Trond Myklebust Cc: Jeff Layton Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 173 +------------------------------------------------ 1 file changed, 3 insertions(+), 170 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index dbf6018fc312..f7902d8c1048 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -2,7 +2,6 @@ #ifndef _LINUX_KERNEL_H #define _LINUX_KERNEL_H - #include #include #include @@ -11,12 +10,14 @@ #include #include #include +#include #include #include #include #include + #include -#include + #include #define STACK_MAGIC 0xdeadbeef @@ -54,125 +55,11 @@ } \ ) -/* - * This looks more complex than it should be. But we need to - * get the type for the ~ right in round_down (it needs to be - * as wide as the result!), and we want to evaluate the macro - * arguments just once each. - */ -#define __round_mask(x, y) ((__typeof__(x))((y)-1)) -/** - * round_up - round up to next specified power of 2 - * @x: the value to round - * @y: multiple to round up to (must be a power of 2) - * - * Rounds @x up to next multiple of @y (which must be a power of 2). - * To perform arbitrary rounding up, use roundup() below. - */ -#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1) -/** - * round_down - round down to next specified power of 2 - * @x: the value to round - * @y: multiple to round down to (must be a power of 2) - * - * Rounds @x down to next multiple of @y (which must be a power of 2). - * To perform arbitrary rounding down, use rounddown() below. - */ -#define round_down(x, y) ((x) & ~__round_mask(x, y)) - #define typeof_member(T, m) typeof(((T*)0)->m) -#define DIV_ROUND_UP __KERNEL_DIV_ROUND_UP - -#define DIV_ROUND_DOWN_ULL(ll, d) \ - ({ unsigned long long _tmp = (ll); do_div(_tmp, d); _tmp; }) - -#define DIV_ROUND_UP_ULL(ll, d) \ - DIV_ROUND_DOWN_ULL((unsigned long long)(ll) + (d) - 1, (d)) - -#if BITS_PER_LONG == 32 -# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP_ULL(ll, d) -#else -# define DIV_ROUND_UP_SECTOR_T(ll,d) DIV_ROUND_UP(ll,d) -#endif - -/** - * roundup - round up to the next specified multiple - * @x: the value to up - * @y: multiple to round up to - * - * Rounds @x up to next multiple of @y. If @y will always be a power - * of 2, consider using the faster round_up(). - */ -#define roundup(x, y) ( \ -{ \ - typeof(y) __y = y; \ - (((x) + (__y - 1)) / __y) * __y; \ -} \ -) -/** - * rounddown - round down to next specified multiple - * @x: the value to round - * @y: multiple to round down to - * - * Rounds @x down to next multiple of @y. If @y will always be a power - * of 2, consider using the faster round_down(). - */ -#define rounddown(x, y) ( \ -{ \ - typeof(x) __x = (x); \ - __x - (__x % (y)); \ -} \ -) - -/* - * Divide positive or negative dividend by positive or negative divisor - * and round to closest integer. Result is undefined for negative - * divisors if the dividend variable type is unsigned and for negative - * dividends if the divisor variable type is unsigned. - */ -#define DIV_ROUND_CLOSEST(x, divisor)( \ -{ \ - typeof(x) __x = x; \ - typeof(divisor) __d = divisor; \ - (((typeof(x))-1) > 0 || \ - ((typeof(divisor))-1) > 0 || \ - (((__x) > 0) == ((__d) > 0))) ? \ - (((__x) + ((__d) / 2)) / (__d)) : \ - (((__x) - ((__d) / 2)) / (__d)); \ -} \ -) -/* - * Same as above but for u64 dividends. divisor must be a 32-bit - * number. - */ -#define DIV_ROUND_CLOSEST_ULL(x, divisor)( \ -{ \ - typeof(divisor) __d = divisor; \ - unsigned long long _tmp = (x) + (__d) / 2; \ - do_div(_tmp, __d); \ - _tmp; \ -} \ -) - -/* - * Multiplies an integer by a fraction, while avoiding unnecessary - * overflow or loss of precision. - */ -#define mult_frac(x, numer, denom)( \ -{ \ - typeof(x) quot = (x) / (denom); \ - typeof(x) rem = (x) % (denom); \ - (quot * (numer)) + ((rem * (numer)) / (denom)); \ -} \ -) - - #define _RET_IP_ (unsigned long)__builtin_return_address(0) #define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) -#define sector_div(a, b) do_div(a, b) - /** * upper_32_bits - return bits 32-63 of a number * @n: the number we're accessing @@ -272,48 +159,6 @@ extern void __cant_migrate(const char *file, int line); #define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0) -/** - * abs - return absolute value of an argument - * @x: the value. If it is unsigned type, it is converted to signed type first. - * char is treated as if it was signed (regardless of whether it really is) - * but the macro's return type is preserved as char. - * - * Return: an absolute value of x. - */ -#define abs(x) __abs_choose_expr(x, long long, \ - __abs_choose_expr(x, long, \ - __abs_choose_expr(x, int, \ - __abs_choose_expr(x, short, \ - __abs_choose_expr(x, char, \ - __builtin_choose_expr( \ - __builtin_types_compatible_p(typeof(x), char), \ - (char)({ signed char __x = (x); __x<0?-__x:__x; }), \ - ((void)0))))))) - -#define __abs_choose_expr(x, type, other) __builtin_choose_expr( \ - __builtin_types_compatible_p(typeof(x), signed type) || \ - __builtin_types_compatible_p(typeof(x), unsigned type), \ - ({ signed type __x = (x); __x < 0 ? -__x : __x; }), other) - -/** - * reciprocal_scale - "scale" a value into range [0, ep_ro) - * @val: value - * @ep_ro: right open interval endpoint - * - * Perform a "reciprocal multiplication" in order to "scale" a value into - * range [0, @ep_ro), where the upper interval endpoint is right-open. - * This is useful, e.g. for accessing a index of an array containing - * @ep_ro elements, for example. Think of it as sort of modulus, only that - * the result isn't that of modulo. ;) Note that if initial input is a - * small value, then result will return 0. - * - * Return: a result based on @val in interval [0, @ep_ro). - */ -static inline u32 reciprocal_scale(u32 val, u32 ep_ro) -{ - return (u32)(((u64) val * ep_ro) >> 32); -} - #if defined(CONFIG_MMU) && \ (defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)) #define might_fault() __might_fault(__FILE__, __LINE__) @@ -515,18 +360,6 @@ extern int __kernel_text_address(unsigned long addr); extern int kernel_text_address(unsigned long addr); extern int func_ptr_is_kernel_text(void *ptr); -u64 int_pow(u64 base, unsigned int exp); -unsigned long int_sqrt(unsigned long); - -#if BITS_PER_LONG < 64 -u32 int_sqrt64(u64 x); -#else -static inline u32 int_sqrt64(u64 x) -{ - return (u32)int_sqrt(x); -} -#endif - #ifdef CONFIG_SMP extern unsigned int sysctl_oops_all_cpu_backtrace; #else -- cgit