Add a circular buffer to store the hw addresses used in the last EXCLUSIVE_HISTORY_LEN exclusive accesses.
When an address is pop'ed from the buffer, its page will be set as not exclusive. In this way we avoid frequent set/unset of a page (causing frequent flushes as well). Suggested-by: Jani Kokkonen <jani.kokko...@huawei.com> Suggested-by: Claudio Fontana <claudio.font...@huawei.com> Signed-off-by: Alvise Rigo <a.r...@virtualopensystems.com> --- cputlb.c | 21 +++++++++++++++++++++ exec.c | 19 +++++++++++++++++++ include/qom/cpu.h | 8 ++++++++ softmmu_llsc_template.h | 1 + vl.c | 3 +++ 5 files changed, 52 insertions(+) diff --git a/cputlb.c b/cputlb.c index 58d6f03..02b0d14 100644 --- a/cputlb.c +++ b/cputlb.c @@ -475,6 +475,27 @@ tb_page_addr_t get_page_addr_code(CPUArchState *env1, target_ulong addr) return qemu_ram_addr_from_host_nofail(p); } +/* Keep a circular array with the last excl_history.length addresses used for + * exclusive accesses. The exiting addresses are marked as non-exclusive. */ +extern CPUExclusiveHistory excl_history; +static inline void excl_history_put_addr(hwaddr addr) +{ + hwaddr last; + + /* Calculate the index of the next exclusive address */ + excl_history.last_idx = (excl_history.last_idx + 1) % excl_history.length; + + last = excl_history.c_array[excl_history.last_idx]; + + /* Unset EXCL bit of the oldest entry */ + if (last != EXCLUSIVE_RESET_ADDR) { + cpu_physical_memory_unset_excl(last); + } + + /* Add a new address, overwriting the oldest one */ + excl_history.c_array[excl_history.last_idx] = addr & TARGET_PAGE_MASK; +} + #define MMUSUFFIX _mmu /* Generates LoadLink/StoreConditional helpers in softmmu_template.h */ diff --git a/exec.c b/exec.c index cefee1b..3c54b92 100644 --- a/exec.c +++ b/exec.c @@ -177,6 +177,25 @@ struct CPUAddressSpace { MemoryListener tcg_as_listener; }; +/* Exclusive memory support */ +CPUExclusiveHistory excl_history; +void cpu_exclusive_history_init(void) +{ + /* Initialize exclusive history for atomic instruction handling. */ + if (tcg_enabled()) { + g_assert(EXCLUSIVE_HISTORY_CPU_LEN * max_cpus <= UINT16_MAX); + excl_history.length = EXCLUSIVE_HISTORY_CPU_LEN * max_cpus; + excl_history.c_array = g_malloc(excl_history.length * sizeof(hwaddr)); + memset(excl_history.c_array, -1, excl_history.length * sizeof(hwaddr)); + } +} + +void cpu_exclusive_history_free(void) +{ + if (tcg_enabled()) { + g_free(excl_history.c_array); + } +} #endif #if !defined(CONFIG_USER_ONLY) diff --git a/include/qom/cpu.h b/include/qom/cpu.h index 014851e..de144f6 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -232,7 +232,15 @@ struct kvm_run; #define TB_JMP_CACHE_SIZE (1 << TB_JMP_CACHE_BITS) /* Atomic insn translation TLB support. */ +typedef struct CPUExclusiveHistory { + uint16_t last_idx; /* index of last insertion */ + uint16_t length; /* history's length, it depends on smp_cpus */ + hwaddr *c_array; /* history's circular array */ +} CPUExclusiveHistory; #define EXCLUSIVE_RESET_ADDR ULLONG_MAX +#define EXCLUSIVE_HISTORY_CPU_LEN 256 +void cpu_exclusive_history_init(void); +void cpu_exclusive_history_free(void); /** * CPUState: diff --git a/softmmu_llsc_template.h b/softmmu_llsc_template.h index ca2ac95..1e24fec 100644 --- a/softmmu_llsc_template.h +++ b/softmmu_llsc_template.h @@ -77,6 +77,7 @@ WORD_TYPE helper_ldlink_name(CPUArchState *env, target_ulong addr, CPUState *cpu; cpu_physical_memory_set_excl(hw_addr); + excl_history_put_addr(hw_addr); CPU_FOREACH(cpu) { if (this_cpu != cpu) { tlb_flush(cpu, 1); diff --git a/vl.c b/vl.c index f043009..b22d99b 100644 --- a/vl.c +++ b/vl.c @@ -547,6 +547,7 @@ static void res_free(void) { g_free(boot_splash_filedata); boot_splash_filedata = NULL; + cpu_exclusive_history_free(); } static int default_driver_check(void *opaque, QemuOpts *opts, Error **errp) @@ -4322,6 +4323,8 @@ int main(int argc, char **argv, char **envp) configure_accelerator(current_machine); + cpu_exclusive_history_init(); + if (qtest_chrdev) { qtest_init(qtest_chrdev, qtest_log, &error_fatal); } -- 2.8.0