From 458aa76d132dc1c3c60be0f0db99bcc0ce1767fc Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Thu, 17 Mar 2016 14:18:56 -0700 Subject: mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range We remove one instace of flush_tlb_range here. That was added by commit f714f4f20e59 ("mm: numa: call MMU notifiers on THP migration"). But the pmdp_huge_clear_flush_notify should have done the require flush for us. Hence remove the extra flush. Signed-off-by: Aneesh Kumar K.V Cc: Mel Gorman Cc: "Kirill A. Shutemov" Cc: Vineet Gupta Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/pgtable.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/asm-generic') diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index c370b261c720..9401f4819891 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -783,6 +783,23 @@ static inline int pmd_clear_huge(pmd_t *pmd) } #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ +#ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +/* + * ARCHes with special requirements for evicting THP backing TLB entries can + * implement this. Otherwise also, it can help optimize normal TLB flush in + * THP regime. stock flush_tlb_range() typically has optimization to nuke the + * entire TLB TLB if flush span is greater than a threshold, which will + * likely be true for a single huge page. Thus a single thp flush will + * invalidate the entire TLB which is not desitable. + * e.g. see arch/arc: flush_pmd_tlb_range + */ +#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) +#else +#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG() +#endif +#endif + #endif /* !__ASSEMBLY__ */ #ifndef io_remap_pfn_range -- cgit v1.2.3 From dfbf2897d00499f94cd53a9806e697392cbfe6a3 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Mar 2016 14:21:12 -0700 Subject: bug: set warn variable before calling WARN() This has hit me a couple of times already. I would be debugging code and the system would simply hang and then reboot. Finally, I found that the problem was caused by WARN_ON_ONCE() and friends. The macro WARN_ON_ONCE(condition) is defined as: static bool __section(.data.unlikely) __warned; int __ret_warn_once = !!(condition); if (unlikely(__ret_warn_once)) if (WARN_ON(!__warned)) __warned = true; unlikely(__ret_warn_once); Which looks great and all. But what I have hit, is an issue when WARN_ON() itself hits the same WARN_ON_ONCE() code. Because, the variable __warned is not yet set. Then it too calls WARN_ON() and that triggers the warning again. It keeps doing this until the stack is overflowed and the system crashes. By setting __warned first before calling WARN_ON() makes the original WARN_ON_ONCE() really only warn once, and not an infinite amount of times if the WARN_ON() also triggers the warning. Signed-off-by: Steven Rostedt Acked-by: Peter Zijlstra (Intel) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/bug.h | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index 630dd2372238..fdf6fa078422 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -110,9 +110,10 @@ extern void warn_slowpath_null(const char *file, const int line); static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ - if (unlikely(__ret_warn_once)) \ - if (WARN_ON(!__warned)) \ - __warned = true; \ + if (unlikely(__ret_warn_once && !__warned)) { \ + __warned = true; \ + WARN_ON(1); \ + } \ unlikely(__ret_warn_once); \ }) @@ -120,9 +121,10 @@ extern void warn_slowpath_null(const char *file, const int line); static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ - if (unlikely(__ret_warn_once)) \ - if (WARN(!__warned, format)) \ - __warned = true; \ + if (unlikely(__ret_warn_once && !__warned)) { \ + __warned = true; \ + WARN(1, format); \ + } \ unlikely(__ret_warn_once); \ }) @@ -130,9 +132,10 @@ extern void warn_slowpath_null(const char *file, const int line); static bool __section(.data.unlikely) __warned; \ int __ret_warn_once = !!(condition); \ \ - if (unlikely(__ret_warn_once)) \ - if (WARN_TAINT(!__warned, taint, format)) \ - __warned = true; \ + if (unlikely(__ret_warn_once && !__warned)) { \ + __warned = true; \ + WARN_TAINT(1, taint, format); \ + } \ unlikely(__ret_warn_once); \ }) -- cgit v1.2.3 From a644fdf029f44f1ff76659154b411afeaeee1f43 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Thu, 17 Mar 2016 14:22:41 -0700 Subject: include/asm-generic/atomic-long.h: force inlining of some atomic_long operations Sometimes gcc mysteriously doesn't inline very small functions we expect to be inlined. See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66122 With this .config: http://busybox.net/~vda/kernel_config_OPTIMIZE_INLINING_and_Os, atomic_long_inc(), atomic_long_dec() and atomic_long_add() functions get deinlined about 40 times. Examples of disassembly: (21 copies, 147 calls): 55 push %rbp 48 89 e5 mov %rsp,%rbp f0 48 ff 07 lock incq (%rdi) 5d pop %rbp c3 retq (4 copies, 14 calls) is similar to inc. (11 copies, 41 calls): 55 push %rbp 48 89 e5 mov %rsp,%rbp f0 48 01 3e lock add %rdi,(%rsi) 5d pop %rbp c3 retq This patch fixes this via s/inline/__always_inline/. Code size decrease after the patch is ~1.3k: text data bss dec hex filename 92203657 20826112 36417536 149447305 8e86289 vmlinux 92202377 20826112 36417536 149446025 8e85d89 vmlinux4_atomiclong_after Signed-off-by: Denys Vlasenko Cc: Ingo Molnar Cc: Thomas Graf Cc: Peter Zijlstra Cc: David Rientjes Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/atomic-long.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/atomic-long.h b/include/asm-generic/atomic-long.h index eb1973bad80b..5e1f345b58dd 100644 --- a/include/asm-generic/atomic-long.h +++ b/include/asm-generic/atomic-long.h @@ -98,14 +98,14 @@ ATOMIC_LONG_ADD_SUB_OP(sub, _release) #define atomic_long_xchg(v, new) \ (ATOMIC_LONG_PFX(_xchg)((ATOMIC_LONG_PFX(_t) *)(v), (new))) -static inline void atomic_long_inc(atomic_long_t *l) +static __always_inline void atomic_long_inc(atomic_long_t *l) { ATOMIC_LONG_PFX(_t) *v = (ATOMIC_LONG_PFX(_t) *)l; ATOMIC_LONG_PFX(_inc)(v); } -static inline void atomic_long_dec(atomic_long_t *l) +static __always_inline void atomic_long_dec(atomic_long_t *l) { ATOMIC_LONG_PFX(_t) *v = (ATOMIC_LONG_PFX(_t) *)l; @@ -113,7 +113,7 @@ static inline void atomic_long_dec(atomic_long_t *l) } #define ATOMIC_LONG_OP(op) \ -static inline void \ +static __always_inline void \ atomic_long_##op(long i, atomic_long_t *l) \ { \ ATOMIC_LONG_PFX(_t) *v = (ATOMIC_LONG_PFX(_t) *)l; \ -- cgit v1.2.3 From 2553b67a1fbe7bf202e4e8070ab0b00d3d3a06a2 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 17 Mar 2016 14:23:04 -0700 Subject: lib/bug.c: use common WARN helper The traceoff_on_warning option doesn't have any effect on s390, powerpc, arm64, parisc, and sh because there are two different types of WARN implementations: 1) The above mentioned architectures treat WARN() as a special case of a BUG() exception. They handle warnings in report_bug() in lib/bug.c. 2) All other architectures just call warn_slowpath_*() directly. Their warnings are handled in warn_slowpath_common() in kernel/panic.c. Support traceoff_on_warning on all architectures and prevent any future divergence by using a single common function to emit the warning. Also remove the '()' from '%pS()', because the parentheses look funky: [ 45.607629] WARNING: at /root/warn_mod/warn_mod.c:17 .init_dummy+0x20/0x40 [warn_mod]() Reported-by: Chunyu Hu Signed-off-by: Josh Poimboeuf Acked-by: Heiko Carstens Tested-by: Prarit Bhargava Acked-by: Prarit Bhargava Acked-by: Steven Rostedt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-generic/bug.h | 6 ++++++ kernel/panic.c | 41 ++++++++++++++++++++++++++--------------- lib/bug.c | 26 ++------------------------ 3 files changed, 34 insertions(+), 39 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h index fdf6fa078422..f90588abbfd4 100644 --- a/include/asm-generic/bug.h +++ b/include/asm-generic/bug.h @@ -81,6 +81,12 @@ extern void warn_slowpath_null(const char *file, const int line); do { printk(arg); __WARN_TAINT(taint); } while (0) #endif +/* used internally by panic.c */ +struct warn_args; + +void __warn(const char *file, int line, void *caller, unsigned taint, + struct pt_regs *regs, struct warn_args *args); + #ifndef WARN_ON #define WARN_ON(condition) ({ \ int __ret_warn_on = !!(condition); \ diff --git a/kernel/panic.c b/kernel/panic.c index d96469de72dc..fa400852bf6c 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -24,6 +24,7 @@ #include #include #include +#include #define PANIC_TIMER_STEP 100 #define PANIC_BLINK_SPD 18 @@ -449,20 +450,25 @@ void oops_exit(void) kmsg_dump(KMSG_DUMP_OOPS); } -#ifdef WANT_WARN_ON_SLOWPATH -struct slowpath_args { +struct warn_args { const char *fmt; va_list args; }; -static void warn_slowpath_common(const char *file, int line, void *caller, - unsigned taint, struct slowpath_args *args) +void __warn(const char *file, int line, void *caller, unsigned taint, + struct pt_regs *regs, struct warn_args *args) { disable_trace_on_warning(); pr_warn("------------[ cut here ]------------\n"); - pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS()\n", - raw_smp_processor_id(), current->pid, file, line, caller); + + if (file) + pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n", + raw_smp_processor_id(), current->pid, file, line, + caller); + else + pr_warn("WARNING: CPU: %d PID: %d at %pS\n", + raw_smp_processor_id(), current->pid, caller); if (args) vprintk(args->fmt, args->args); @@ -479,20 +485,27 @@ static void warn_slowpath_common(const char *file, int line, void *caller, } print_modules(); - dump_stack(); + + if (regs) + show_regs(regs); + else + dump_stack(); + print_oops_end_marker(); + /* Just a warning, don't kill lockdep. */ add_taint(taint, LOCKDEP_STILL_OK); } +#ifdef WANT_WARN_ON_SLOWPATH void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...) { - struct slowpath_args args; + struct warn_args args; args.fmt = fmt; va_start(args.args, fmt); - warn_slowpath_common(file, line, __builtin_return_address(0), - TAINT_WARN, &args); + __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, + &args); va_end(args.args); } EXPORT_SYMBOL(warn_slowpath_fmt); @@ -500,20 +513,18 @@ EXPORT_SYMBOL(warn_slowpath_fmt); void warn_slowpath_fmt_taint(const char *file, int line, unsigned taint, const char *fmt, ...) { - struct slowpath_args args; + struct warn_args args; args.fmt = fmt; va_start(args.args, fmt); - warn_slowpath_common(file, line, __builtin_return_address(0), - taint, &args); + __warn(file, line, __builtin_return_address(0), taint, NULL, &args); va_end(args.args); } EXPORT_SYMBOL(warn_slowpath_fmt_taint); void warn_slowpath_null(const char *file, int line) { - warn_slowpath_common(file, line, __builtin_return_address(0), - TAINT_WARN, NULL); + __warn(file, line, __builtin_return_address(0), TAINT_WARN, NULL, NULL); } EXPORT_SYMBOL(warn_slowpath_null); #endif diff --git a/lib/bug.c b/lib/bug.c index 6cde380f09de..bc3656e944d2 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -167,30 +167,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) if (warning) { /* this is a WARN_ON rather than BUG/BUG_ON */ - pr_warn("------------[ cut here ]------------\n"); - - if (file) - pr_warn("WARNING: at %s:%u\n", file, line); - else - pr_warn("WARNING: at %p [verbose debug info unavailable]\n", - (void *)bugaddr); - - if (panic_on_warn) { - /* - * This thread may hit another WARN() in the panic path. - * Resetting this prevents additional WARN() from - * panicking the system on this thread. Other threads - * are blocked by the panic_mutex in panic(). - */ - panic_on_warn = 0; - panic("panic_on_warn set ...\n"); - } - - print_modules(); - show_regs(regs); - print_oops_end_marker(); - /* Just a warning, don't kill lockdep. */ - add_taint(BUG_GET_TAINT(bug), LOCKDEP_STILL_OK); + __warn(file, line, (void *)bugaddr, BUG_GET_TAINT(bug), regs, + NULL); return BUG_TRAP_TYPE_WARN; } -- cgit v1.2.3