/* * Copyright (C) 2016 Red Hat, Inc. * Author: Michael S. Tsirkin * This work is licensed under the terms of the GNU GPL, version 2. * * Common macros and functions for ring benchmarking. */ #ifndef MAIN_H #define MAIN_H #include extern bool do_exit; #if defined(__x86_64__) || defined(__i386__) #include "x86intrin.h" static inline void wait_cycles(unsigned long long cycles) { unsigned long long t; t = __rdtsc(); while (__rdtsc() - t < cycles) {} } #define VMEXIT_CYCLES 500 #define VMENTRY_CYCLES 500 #elif defined(__s390x__) static inline void wait_cycles(unsigned long long cycles) { asm volatile("0: brctg %0,0b" : : "d" (cycles)); } /* tweak me */ #define VMEXIT_CYCLES 200 #define VMENTRY_CYCLES 200 #else static inline void wait_cycles(unsigned long long cycles) { _Exit(5); } #define VMEXIT_CYCLES 0 #define VMENTRY_CYCLES 0 #endif static inline void vmexit(void) { if (!do_exit) return; wait_cycles(VMEXIT_CYCLES); } static inline void vmentry(void) { if (!do_exit) return; wait_cycles(VMENTRY_CYCLES); } /* implemented by ring */ void alloc_ring(void); /* guest side */ int add_inbuf(unsigned, void *, void *); void *get_buf(unsigned *, void **); void disable_call(); bool used_empty(); bool enable_call(); void kick_available(); /* host side */ void disable_kick(); bool avail_empty(); bool enable_kick(); bool use_buf(unsigned *, void **); void call_used(); /* implemented by main */ extern bool do_sleep; void kick(void); void wait_for_kick(void); void call(void); void wait_for_call(void); extern unsigned ring_size; /* Compiler barrier - similar to what Linux uses */ #define barrier() asm volatile("" ::: "memory") /* Is there a portable way to do this? */ #if defined(__x86_64__) || defined(__i386__) #define cpu_relax() asm ("rep; nop" ::: "memory") #elif defined(__s390x__) #define cpu_relax() barrier() #else #define cpu_relax() assert(0) #endif extern bool do_relax; static inline void busy_wait(void) { if (do_relax) cpu_relax(); else /* prevent compiler from removing busy loops */ barrier(); } /* * Not using __ATOMIC_SEQ_CST since gcc docs say they are only synchronized * with other __ATOMIC_SEQ_CST calls. */ #define smp_mb() __sync_synchronize() /* * This abuses the atomic builtins for thread fences, and * adds a compiler barrier. */ #define smp_release() do { \ barrier(); \ __atomic_thread_fence(__ATOMIC_RELEASE); \ } while (0) #define smp_acquire() do { \ __atomic_thread_fence(__ATOMIC_ACQUIRE); \ barrier(); \ } while (0) #endif 'committer'>committer
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authorDexuan Cui <decui@microsoft.com>2017-01-28 11:46:02 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-01-31 10:59:48 +0100
commit433e19cf33d34bb6751c874a9c00980552fe508c (patch)
treece6547ef2987fbb289fa28f03536328a42781651 /include/uapi/sound/hdspm.h
parent191e885a2e130e639bb0c8ee350d7047294f2ce6 (diff)
Drivers: hv: vmbus: finally fix hv_need_to_signal_on_read()
Commit a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()") added the proper mb(), but removed the test "prev_write_sz < pending_sz" when making the signal decision. As a result, the guest can signal the host unnecessarily, and then the host can throttle the guest because the host thinks the guest is buggy or malicious; finally the user running stress test can perceive intermittent freeze of the guest. This patch brings back the test, and properly handles the in-place consumption APIs used by NetVSC (see get_next_pkt_raw(), put_pkt_raw() and commit_rd_index()). Fixes: a389fcfd2cb5 ("Drivers: hv: vmbus: Fix signaling logic in hv_need_to_signal_on_read()") Signed-off-by: Dexuan Cui <decui@microsoft.com> Reported-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Tested-by: Rolf Neugebauer <rolf.neugebauer@docker.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: K. Y. Srinivasan <kys@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/uapi/sound/hdspm.h')