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view src/os_cpu/linux_zero/vm/atomic_linux_zero.inline.hpp @ 1837:c99c53f07c14
6692906: CMS: parallel concurrent marking may be prone to hanging or stalling mutators for periods of time
Summary: Inserted missing yield(check)s in closures used during the work-stealing phase of parallel concurrent marking, a missing synchronous yield-request in the cms perm gen allocation path, and a terminator-terminator for the offer_termination invocation that monitors the yield status of the concurrent marking task. Elaborated some documentation comments and made some task queue termination loop flags configurable at start-up to aid debugging in the field.
Reviewed-by: jmasa, johnc, poonam
author | ysr |
---|---|
date | Wed, 29 Sep 2010 16:17:02 -0700 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
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/* * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved. * Copyright 2007, 2008 Red Hat, Inc. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ // Implementation of class atomic #ifdef M68K /* * __m68k_cmpxchg * * Atomically store newval in *ptr if *ptr is equal to oldval for user space. * Returns newval on success and oldval if no exchange happened. * This implementation is processor specific and works on * 68020 68030 68040 and 68060. * * It will not work on ColdFire, 68000 and 68010 since they lack the CAS * instruction. * Using a kernelhelper would be better for arch complete implementation. * */ static inline int __m68k_cmpxchg(int oldval, int newval, volatile int *ptr) { int ret; __asm __volatile ("cas%.l %0,%2,%1" : "=d" (ret), "+m" (*(ptr)) : "d" (newval), "0" (oldval)); return ret; } /* Perform an atomic compare and swap: if the current value of `*PTR' is OLDVAL, then write NEWVAL into `*PTR'. Return the contents of `*PTR' before the operation.*/ static inline int m68k_compare_and_swap(volatile int *ptr, int oldval, int newval) { for (;;) { int prev = *ptr; if (prev != oldval) return prev; if (__m68k_cmpxchg (prev, newval, ptr) == newval) // Success. return prev; // We failed even though prev == oldval. Try again. } } /* Atomically add an int to memory. */ static inline int m68k_add_and_fetch(volatile int *ptr, int add_value) { for (;;) { // Loop until success. int prev = *ptr; if (__m68k_cmpxchg (prev, prev + add_value, ptr) == prev + add_value) return prev + add_value; } } /* Atomically write VALUE into `*PTR' and returns the previous contents of `*PTR'. */ static inline int m68k_lock_test_and_set(volatile int *ptr, int newval) { for (;;) { // Loop until success. int prev = *ptr; if (__m68k_cmpxchg (prev, newval, ptr) == prev) return prev; } } #endif // M68K #ifdef ARM /* * __kernel_cmpxchg * * Atomically store newval in *ptr if *ptr is equal to oldval for user space. * Return zero if *ptr was changed or non-zero if no exchange happened. * The C flag is also set if *ptr was changed to allow for assembly * optimization in the calling code. * */ typedef int (__kernel_cmpxchg_t)(int oldval, int newval, volatile int *ptr); #define __kernel_cmpxchg (*(__kernel_cmpxchg_t *) 0xffff0fc0) /* Perform an atomic compare and swap: if the current value of `*PTR' is OLDVAL, then write NEWVAL into `*PTR'. Return the contents of `*PTR' before the operation.*/ static inline int arm_compare_and_swap(volatile int *ptr, int oldval, int newval) { for (;;) { int prev = *ptr; if (prev != oldval) return prev; if (__kernel_cmpxchg (prev, newval, ptr) == 0) // Success. return prev; // We failed even though prev == oldval. Try again. } } /* Atomically add an int to memory. */ static inline int arm_add_and_fetch(volatile int *ptr, int add_value) { for (;;) { // Loop until a __kernel_cmpxchg succeeds. int prev = *ptr; if (__kernel_cmpxchg (prev, prev + add_value, ptr) == 0) return prev + add_value; } } /* Atomically write VALUE into `*PTR' and returns the previous contents of `*PTR'. */ static inline int arm_lock_test_and_set(volatile int *ptr, int newval) { for (;;) { // Loop until a __kernel_cmpxchg succeeds. int prev = *ptr; if (__kernel_cmpxchg (prev, newval, ptr) == 0) return prev; } } #endif // ARM inline void Atomic::store(jint store_value, volatile jint* dest) { *dest = store_value; } inline void Atomic::store_ptr(intptr_t store_value, intptr_t* dest) { *dest = store_value; } inline jint Atomic::add(jint add_value, volatile jint* dest) { #ifdef ARM return arm_add_and_fetch(dest, add_value); #else #ifdef M68K return m68k_add_and_fetch(dest, add_value); #else return __sync_add_and_fetch(dest, add_value); #endif // M68K #endif // ARM } inline intptr_t Atomic::add_ptr(intptr_t add_value, volatile intptr_t* dest) { #ifdef ARM return arm_add_and_fetch(dest, add_value); #else #ifdef M68K return m68k_add_and_fetch(dest, add_value); #else return __sync_add_and_fetch(dest, add_value); #endif // M68K #endif // ARM } inline void* Atomic::add_ptr(intptr_t add_value, volatile void* dest) { return (void *) add_ptr(add_value, (volatile intptr_t *) dest); } inline void Atomic::inc(volatile jint* dest) { add(1, dest); } inline void Atomic::inc_ptr(volatile intptr_t* dest) { add_ptr(1, dest); } inline void Atomic::inc_ptr(volatile void* dest) { add_ptr(1, dest); } inline void Atomic::dec(volatile jint* dest) { add(-1, dest); } inline void Atomic::dec_ptr(volatile intptr_t* dest) { add_ptr(-1, dest); } inline void Atomic::dec_ptr(volatile void* dest) { add_ptr(-1, dest); } inline jint Atomic::xchg(jint exchange_value, volatile jint* dest) { #ifdef ARM return arm_lock_test_and_set(dest, exchange_value); #else #ifdef M68K return m68k_lock_test_and_set(dest, exchange_value); #else // __sync_lock_test_and_set is a bizarrely named atomic exchange // operation. Note that some platforms only support this with the // limitation that the only valid value to store is the immediate // constant 1. There is a test for this in JNI_CreateJavaVM(). return __sync_lock_test_and_set (dest, exchange_value); #endif // M68K #endif // ARM } inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value, volatile intptr_t* dest) { #ifdef ARM return arm_lock_test_and_set(dest, exchange_value); #else #ifdef M68K return m68k_lock_test_and_set(dest, exchange_value); #else return __sync_lock_test_and_set (dest, exchange_value); #endif // M68K #endif // ARM } inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) { return (void *) xchg_ptr((intptr_t) exchange_value, (volatile intptr_t*) dest); } inline jint Atomic::cmpxchg(jint exchange_value, volatile jint* dest, jint compare_value) { #ifdef ARM return arm_compare_and_swap(dest, compare_value, exchange_value); #else #ifdef M68K return m68k_compare_and_swap(dest, compare_value, exchange_value); #else return __sync_val_compare_and_swap(dest, compare_value, exchange_value); #endif // M68K #endif // ARM } inline jlong Atomic::cmpxchg(jlong exchange_value, volatile jlong* dest, jlong compare_value) { return __sync_val_compare_and_swap(dest, compare_value, exchange_value); } inline intptr_t Atomic::cmpxchg_ptr(intptr_t exchange_value, volatile intptr_t* dest, intptr_t compare_value) { #ifdef ARM return arm_compare_and_swap(dest, compare_value, exchange_value); #else #ifdef M68K return m68k_compare_and_swap(dest, compare_value, exchange_value); #else return __sync_val_compare_and_swap(dest, compare_value, exchange_value); #endif // M68K #endif // ARM } inline void* Atomic::cmpxchg_ptr(void* exchange_value, volatile void* dest, void* compare_value) { return (void *) cmpxchg_ptr((intptr_t) exchange_value, (volatile intptr_t*) dest, (intptr_t) compare_value); }