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[98.147.121.51]) by smtp.gmail.com with ESMTPSA id e192-v6sm9642897pfg.187.2018.06.21.10.36.40 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 21 Jun 2018 10:36:42 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Thu, 21 Jun 2018 07:36:34 -1000 Message-Id: <20180621173635.21537-2-richard.henderson@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180621173635.21537-1-richard.henderson@linaro.org> References: <20180621173635.21537-1-richard.henderson@linaro.org> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400e:c00::241 Subject: [Qemu-devel] [PATCH 1/2] exec: Split mmap_lock to mmap_rdlock/mmap_wrlock X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cota@braap.org, laurent@vivier.eu, qemu-arm@nongnu.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" Do not yet change the backing implementation, but split intent of users for reading or modification of the memory map. Uses within accel/tcg/ and exec.c are expecting exclusivity while manipulating TranslationBlock data structures, so consider those writers. Signed-off-by: Richard Henderson --- include/exec/exec-all.h | 6 ++++-- accel/tcg/cpu-exec.c | 8 ++++---- accel/tcg/translate-all.c | 4 ++-- bsd-user/mmap.c | 18 ++++++++++++++---- exec.c | 6 +++--- linux-user/elfload.c | 2 +- linux-user/mips/cpu_loop.c | 2 +- linux-user/mmap.c | 22 ++++++++++++++++------ linux-user/ppc/cpu_loop.c | 2 +- linux-user/syscall.c | 4 ++-- target/arm/sve_helper.c | 10 +++------- target/xtensa/op_helper.c | 2 +- 12 files changed, 52 insertions(+), 34 deletions(-) -- 2.17.1 diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h index 25a6f28ab8..a57764b693 100644 --- a/include/exec/exec-all.h +++ b/include/exec/exec-all.h @@ -468,7 +468,8 @@ void tlb_fill(CPUState *cpu, target_ulong addr, int size, #endif #if defined(CONFIG_USER_ONLY) -void mmap_lock(void); +void mmap_rdlock(void); +void mmap_wrlock(void); void mmap_unlock(void); bool have_mmap_lock(void); @@ -477,7 +478,8 @@ static inline tb_page_addr_t get_page_addr_code(CPUArchState *env1, target_ulong return addr; } #else -static inline void mmap_lock(void) {} +static inline void mmap_rdlock(void) {} +static inline void mmap_wrlock(void) {} static inline void mmap_unlock(void) {} /* cputlb.c */ diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index c738b7f7d6..59bdedb6c7 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -212,7 +212,7 @@ static void cpu_exec_nocache(CPUState *cpu, int max_cycles, We only end up here when an existing TB is too long. */ cflags |= MIN(max_cycles, CF_COUNT_MASK); - mmap_lock(); + mmap_wrlock(); tb = tb_gen_code(cpu, orig_tb->pc, orig_tb->cs_base, orig_tb->flags, cflags); tb->orig_tb = orig_tb; @@ -222,7 +222,7 @@ static void cpu_exec_nocache(CPUState *cpu, int max_cycles, trace_exec_tb_nocache(tb, tb->pc); cpu_tb_exec(cpu, tb); - mmap_lock(); + mmap_wrlock(); tb_phys_invalidate(tb, -1); mmap_unlock(); tcg_tb_remove(tb); @@ -243,7 +243,7 @@ void cpu_exec_step_atomic(CPUState *cpu) if (sigsetjmp(cpu->jmp_env, 0) == 0) { tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, cf_mask); if (tb == NULL) { - mmap_lock(); + mmap_wrlock(); tb = tb_gen_code(cpu, pc, cs_base, flags, cflags); mmap_unlock(); } @@ -397,7 +397,7 @@ static inline TranslationBlock *tb_find(CPUState *cpu, tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, cf_mask); if (tb == NULL) { - mmap_lock(); + mmap_wrlock(); tb = tb_gen_code(cpu, pc, cs_base, flags, cf_mask); mmap_unlock(); /* We add the TB in the virtual pc hash table for the fast lookup */ diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index f0c3fd4d03..48a71af392 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -1214,7 +1214,7 @@ static gboolean tb_host_size_iter(gpointer key, gpointer value, gpointer data) /* flush all the translation blocks */ static void do_tb_flush(CPUState *cpu, run_on_cpu_data tb_flush_count) { - mmap_lock(); + mmap_wrlock(); /* If it is already been done on request of another CPU, * just retry. */ @@ -2563,7 +2563,7 @@ int page_unprotect(target_ulong address, uintptr_t pc) /* Technically this isn't safe inside a signal handler. However we know this only ever happens in a synchronous SEGV handler, so in practice it seems to be ok. */ - mmap_lock(); + mmap_wrlock(); p = page_find(address >> TARGET_PAGE_BITS); if (!p) { diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c index 17f4cd80aa..4f6fe3cf4e 100644 --- a/bsd-user/mmap.c +++ b/bsd-user/mmap.c @@ -28,13 +28,23 @@ static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; static __thread int mmap_lock_count; -void mmap_lock(void) +static void mmap_lock_internal(void) { if (mmap_lock_count++ == 0) { pthread_mutex_lock(&mmap_mutex); } } +void mmap_rdlock(void) +{ + mmap_lock_internal(); +} + +void mmap_wrlock(void) +{ + mmap_lock_internal(); +} + void mmap_unlock(void) { if (--mmap_lock_count == 0) { @@ -87,7 +97,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot) if (len == 0) return 0; - mmap_lock(); + mmap_wrlock(); host_start = start & qemu_host_page_mask; host_end = HOST_PAGE_ALIGN(end); if (start > host_start) { @@ -248,7 +258,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; unsigned long host_start; - mmap_lock(); + mmap_wrlock(); #ifdef DEBUG_MMAP { printf("mmap: start=0x" TARGET_FMT_lx @@ -424,7 +434,7 @@ int target_munmap(abi_ulong start, abi_ulong len) len = TARGET_PAGE_ALIGN(len); if (len == 0) return -EINVAL; - mmap_lock(); + mmap_wrlock(); end = start + len; real_start = start & qemu_host_page_mask; real_end = HOST_PAGE_ALIGN(end); diff --git a/exec.c b/exec.c index 28f9bdcbf9..27d9c2ab0c 100644 --- a/exec.c +++ b/exec.c @@ -1030,7 +1030,7 @@ const char *parse_cpu_model(const char *cpu_model) #if defined(CONFIG_USER_ONLY) static void breakpoint_invalidate(CPUState *cpu, target_ulong pc) { - mmap_lock(); + mmap_wrlock(); tb_invalidate_phys_page_range(pc, pc + 1, 0); mmap_unlock(); } @@ -2743,7 +2743,7 @@ static void check_watchpoint(int offset, int len, MemTxAttrs attrs, int flags) } cpu->watchpoint_hit = wp; - mmap_lock(); + mmap_wrlock(); tb_check_watchpoint(cpu); if (wp->flags & BP_STOP_BEFORE_ACCESS) { cpu->exception_index = EXCP_DEBUG; @@ -3143,7 +3143,7 @@ static void invalidate_and_set_dirty(MemoryRegion *mr, hwaddr addr, } if (dirty_log_mask & (1 << DIRTY_MEMORY_CODE)) { assert(tcg_enabled()); - mmap_lock(); + mmap_wrlock(); tb_invalidate_phys_range(addr, addr + length); mmap_unlock(); dirty_log_mask &= ~(1 << DIRTY_MEMORY_CODE); diff --git a/linux-user/elfload.c b/linux-user/elfload.c index bdb023b477..9ef8ab972a 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2196,7 +2196,7 @@ static void load_elf_image(const char *image_name, int image_fd, info->nsegs = 0; info->pt_dynamic_addr = 0; - mmap_lock(); + mmap_wrlock(); /* Find the maximum size of the image and allocate an appropriate amount of memory to handle that. */ diff --git a/linux-user/mips/cpu_loop.c b/linux-user/mips/cpu_loop.c index 084ad6a041..9d7399c6d1 100644 --- a/linux-user/mips/cpu_loop.c +++ b/linux-user/mips/cpu_loop.c @@ -405,7 +405,7 @@ static int do_store_exclusive(CPUMIPSState *env) addr = env->lladdr; page_addr = addr & TARGET_PAGE_MASK; start_exclusive(); - mmap_lock(); + mmap_rdlock(); flags = page_get_flags(page_addr); if ((flags & PAGE_READ) == 0) { segv = 1; diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 9168a2051c..71b6bed5e2 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -27,13 +27,23 @@ static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; static __thread int mmap_lock_count; -void mmap_lock(void) +static void mmap_lock_internal(void) { if (mmap_lock_count++ == 0) { pthread_mutex_lock(&mmap_mutex); } } +void mmap_rdlock(void) +{ + mmap_lock_internal(); +} + +void mmap_wrlock(void) +{ + mmap_lock_internal(); +} + void mmap_unlock(void) { if (--mmap_lock_count == 0) { @@ -87,7 +97,7 @@ int target_mprotect(abi_ulong start, abi_ulong len, int prot) if (len == 0) return 0; - mmap_lock(); + mmap_wrlock(); host_start = start & qemu_host_page_mask; host_end = HOST_PAGE_ALIGN(end); if (start > host_start) { @@ -251,7 +261,7 @@ static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size) /* * Find and reserve a free memory area of size 'size'. The search * starts at 'start'. - * It must be called with mmap_lock() held. + * It must be called with mmap_wrlock() held. * Return -1 if error. */ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size) @@ -364,7 +374,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, { abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; - mmap_lock(); + mmap_wrlock(); #ifdef DEBUG_MMAP { printf("mmap: start=0x" TARGET_ABI_FMT_lx @@ -627,7 +637,7 @@ int target_munmap(abi_ulong start, abi_ulong len) return -TARGET_EINVAL; } - mmap_lock(); + mmap_wrlock(); end = start + len; real_start = start & qemu_host_page_mask; real_end = HOST_PAGE_ALIGN(end); @@ -688,7 +698,7 @@ abi_long target_mremap(abi_ulong old_addr, abi_ulong old_size, return -1; } - mmap_lock(); + mmap_wrlock(); if (flags & MREMAP_FIXED) { host_addr = mremap(g2h(old_addr), old_size, new_size, diff --git a/linux-user/ppc/cpu_loop.c b/linux-user/ppc/cpu_loop.c index 2fb516cb00..d7cd5f4a50 100644 --- a/linux-user/ppc/cpu_loop.c +++ b/linux-user/ppc/cpu_loop.c @@ -76,7 +76,7 @@ static int do_store_exclusive(CPUPPCState *env) addr = env->reserve_ea; page_addr = addr & TARGET_PAGE_MASK; start_exclusive(); - mmap_lock(); + mmap_rdlock(); flags = page_get_flags(page_addr); if ((flags & PAGE_READ) == 0) { segv = 1; diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 2117fb13b4..4104444764 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -4989,7 +4989,7 @@ static inline abi_ulong do_shmat(CPUArchState *cpu_env, return -TARGET_EINVAL; } - mmap_lock(); + mmap_wrlock(); if (shmaddr) host_raddr = shmat(shmid, (void *)g2h(shmaddr), shmflg); @@ -5034,7 +5034,7 @@ static inline abi_long do_shmdt(abi_ulong shmaddr) int i; abi_long rv; - mmap_lock(); + mmap_wrlock(); for (i = 0; i < N_SHM_REGIONS; ++i) { if (shm_regions[i].in_use && shm_regions[i].start == shmaddr) { diff --git a/target/arm/sve_helper.c b/target/arm/sve_helper.c index cd3dfc8b26..086547c7e5 100644 --- a/target/arm/sve_helper.c +++ b/target/arm/sve_helper.c @@ -4071,10 +4071,6 @@ record_fault(CPUARMState *env, intptr_t i, intptr_t oprsz) * between page_check_range and the load operation. We expect the * usual case to have no faults at all, so we check the whole range * first and if successful defer to the normal load operation. - * - * TODO: Change mmap_lock to a rwlock so that multiple readers - * can run simultaneously. This will probably help other uses - * within QEMU as well. */ #define DO_LDFF1(PART, FN, TYPEE, TYPEM, H) \ static void do_sve_ldff1##PART(CPUARMState *env, void *vd, void *vg, \ @@ -4107,7 +4103,7 @@ void HELPER(sve_ldff1##PART)(CPUARMState *env, void *vg, \ intptr_t oprsz = simd_oprsz(desc); \ unsigned rd = simd_data(desc); \ void *vd = &env->vfp.zregs[rd]; \ - mmap_lock(); \ + mmap_rdlock(); \ if (likely(page_check_range(addr, oprsz, PAGE_READ) == 0)) { \ do_sve_ld1##PART(env, vd, vg, addr, oprsz, GETPC()); \ } else { \ @@ -4126,7 +4122,7 @@ void HELPER(sve_ldnf1##PART)(CPUARMState *env, void *vg, \ intptr_t oprsz = simd_oprsz(desc); \ unsigned rd = simd_data(desc); \ void *vd = &env->vfp.zregs[rd]; \ - mmap_lock(); \ + mmap_rdlock(); \ if (likely(page_check_range(addr, oprsz, PAGE_READ) == 0)) { \ do_sve_ld1##PART(env, vd, vg, addr, oprsz, GETPC()); \ } else { \ @@ -4500,7 +4496,7 @@ void HELPER(NAME)(CPUARMState *env, void *vd, void *vg, void *vm, \ unsigned scale = simd_data(desc); \ uintptr_t ra = GETPC(); \ bool first = true; \ - mmap_lock(); \ + mmap_rdlock(); \ for (i = 0; i < oprsz; i++) { \ uint16_t pg = *(uint16_t *)(vg + H1_2(i >> 3)); \ do { \ diff --git a/target/xtensa/op_helper.c b/target/xtensa/op_helper.c index 8a8c763c63..251fa27d43 100644 --- a/target/xtensa/op_helper.c +++ b/target/xtensa/op_helper.c @@ -114,7 +114,7 @@ static void tb_invalidate_virtual_addr(CPUXtensaState *env, uint32_t vaddr) static void tb_invalidate_virtual_addr(CPUXtensaState *env, uint32_t vaddr) { - mmap_lock(); + mmap_wrlock(); tb_invalidate_phys_range(vaddr, vaddr + 1); mmap_unlock(); } From patchwork Thu Jun 21 17:36:35 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 139557 Delivered-To: patch@linaro.org Received: by 2002:a2e:970d:0:0:0:0:0 with SMTP id r13-v6csp2368534lji; Thu, 21 Jun 2018 10:40:49 -0700 (PDT) X-Google-Smtp-Source: ADUXVKLYsXMOsoKjIugUgeQPo5Bnuv6H9Z6PjqFEcLuzhYDFO5MBgqKDNi24suLAVaNT+vX9QCiS X-Received: by 2002:a37:2c87:: with SMTP id s129-v6mr21299975qkh.68.1529602849685; Thu, 21 Jun 2018 10:40:49 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1529602849; cv=none; d=google.com; s=arc-20160816; b=0D05EHB2QRYgqA2HMWb+qQe+tb9EdjeXxnNSWIzpmMfewZK8SZhNdWkmF+wPbNBS+3 MoUwDlllXuRzzsk0Ax4uZ+WUmxvEYyChD8at9SjqOykmM2vHgTDkdkY0WkwzSgVzCd/r NZtWyI9Cjdeq08BBhBVXab5UPF0pPT2Ab6TIvWmDbvCZ98i627VhXT4xJoAwWjXEJPfU zrSPnaV3Na1eggywK0QHBDVIW5cVSU7G6JrykFycqQu+Nau+zSHH3bm4utNOexT+BzR/ BkQc3GE6mYRGor9UhuXwBev444dAbBY9K+KiWwqpicQlW61uxGH4xxNOlOcoDHq0K28N reKw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:cc:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:to:from:dkim-signature:arc-authentication-results; bh=dAGvimUHj8i54umH7c4ck5t1ysicwOLXz6VvcrwBBVo=; b=FCX4uxGlEIIXmyxhsGaI55boqLoy50n6V7CJmQQA+SY42/HSt+rZLD0qTRZiD8EN3D iZjzBorYc1xMwEPvUR/wTjPUBAx8P9WPJONMZPvsypiuHMrna/bAhJBF6vZVMjWsPlhp K7z4SBLQGzJk1QMpWh0tsiUypyFiJEeLBtBkANrwRWimNQuMdH5D0ocWbV5V2xnZ/7Pk xXS1Cu54NRFmi9T+5r0YnBbCQ0qKHNmrsE4aYc+TkEftsu1wg2PiUMc1IGRpZ0y31PMo Y42BrKWZwPAjlESW4W8nkA6fNqm/9IWCqV7QyfcP+qxseLjV6Mjf0PxZF4EoLG7/BxcF lG2Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=fail header.i=@linaro.org header.s=google header.b=a3dng0iw; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=linaro.org Return-Path: Received: from lists.gnu.org (lists.gnu.org. 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[98.147.121.51]) by smtp.gmail.com with ESMTPSA id e192-v6sm9642897pfg.187.2018.06.21.10.36.43 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 21 Jun 2018 10:36:43 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Thu, 21 Jun 2018 07:36:35 -1000 Message-Id: <20180621173635.21537-3-richard.henderson@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180621173635.21537-1-richard.henderson@linaro.org> References: <20180621173635.21537-1-richard.henderson@linaro.org> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400e:c00::22f Subject: [Qemu-devel] [PATCH 2/2] linux-user: Use pthread_rwlock_t for mmap_rd/wrlock X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cota@braap.org, laurent@vivier.eu, qemu-arm@nongnu.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" Change the implementation of these functions to use an actual reader/writer lock, allowing multiple simultaneous readers. Signed-off-by: Richard Henderson --- linux-user/mmap.c | 52 ++++++++++++++++++++++++++++------------------- 1 file changed, 31 insertions(+), 21 deletions(-) -- 2.17.1 diff --git a/linux-user/mmap.c b/linux-user/mmap.c index 71b6bed5e2..2dc133515a 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -24,52 +24,62 @@ //#define DEBUG_MMAP -static pthread_mutex_t mmap_mutex = PTHREAD_MUTEX_INITIALIZER; -static __thread int mmap_lock_count; - -static void mmap_lock_internal(void) -{ - if (mmap_lock_count++ == 0) { - pthread_mutex_lock(&mmap_mutex); - } -} +static pthread_rwlock_t mmap_rwlock = PTHREAD_RWLOCK_INITIALIZER; +/* Bit 0 indicates reading; bit 1 indicates writing; bits 2+ are count-1. */ +static __thread int mmap_lock_held; void mmap_rdlock(void) { - mmap_lock_internal(); + if (likely(mmap_lock_held == 0)) { + pthread_rwlock_rdlock(&mmap_rwlock); + mmap_lock_held = 1; + } else { + /* can read-lock when write-lock held */ + mmap_lock_held += 4; + } } void mmap_wrlock(void) { - mmap_lock_internal(); + if (likely(mmap_lock_held == 0)) { + pthread_rwlock_rdlock(&mmap_rwlock); + mmap_lock_held = 2; + } else { + /* cannot upgrade a read-lock to a write-lock */ + assert((mmap_lock_held & 1) == 0); + mmap_lock_held += 4; + } } void mmap_unlock(void) { - if (--mmap_lock_count == 0) { - pthread_mutex_unlock(&mmap_mutex); + assert(mmap_lock_held > 0); + mmap_lock_held -= 4; + if (mmap_lock_held < 0) { + mmap_lock_held = 0; + pthread_rwlock_unlock(&mmap_rwlock); } } bool have_mmap_lock(void) { - return mmap_lock_count > 0 ? true : false; + return mmap_lock_held != 0; } /* Grab lock to make sure things are in a consistent state after fork(). */ void mmap_fork_start(void) { - if (mmap_lock_count) - abort(); - pthread_mutex_lock(&mmap_mutex); + assert(mmap_lock_held == 0); + pthread_rwlock_wrlock(&mmap_rwlock); } void mmap_fork_end(int child) { - if (child) - pthread_mutex_init(&mmap_mutex, NULL); - else - pthread_mutex_unlock(&mmap_mutex); + if (child) { + pthread_rwlock_init(&mmap_rwlock, NULL); + } else { + pthread_rwlock_unlock(&mmap_rwlock); + } } /* NOTE: all the constants are the HOST ones, but addresses are target. */