This API is no longer used.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
include/qemu/stats64.h | 199 -----------------------------------------
util/stats64.c | 148 ------------------------------
util/meson.build | 1 -
3 files changed, 348 deletions(-)
delete mode 100644 include/qemu/stats64.h
delete mode 100644 util/stats64.c
diff --git a/include/qemu/stats64.h b/include/qemu/stats64.h
deleted file mode 100644
index 99b5cb724a..0000000000
--- a/include/qemu/stats64.h
+++ /dev/null
@@ -1,199 +0,0 @@
-/*
- * Atomic operations on 64-bit quantities.
- *
- * Copyright (C) 2017 Red Hat, Inc.
- *
- * Author: Paolo Bonzini <pbonzini@redhat.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- */
-
-#ifndef QEMU_STATS64_H
-#define QEMU_STATS64_H
-
-#include "qemu/atomic.h"
-
-/* This provides atomic operations on 64-bit type, using a reader-writer
- * spinlock on architectures that do not have 64-bit accesses. Even on
- * those architectures, it tries hard not to take the lock.
- */
-
-typedef struct Stat64 {
-#ifdef CONFIG_ATOMIC64
- aligned_uint64_t value;
-#else
- uint32_t low, high;
- uint32_t lock;
-#endif
-} Stat64;
-
-#ifdef CONFIG_ATOMIC64
-static inline void stat64_init(Stat64 *s, uint64_t value)
-{
- /* This is not guaranteed to be atomic! */
- *s = (Stat64) { value };
-}
-
-static inline uint64_t stat64_get(const Stat64 *s)
-{
- return qatomic_read__nocheck(&s->value);
-}
-
-static inline void stat64_set(Stat64 *s, uint64_t value)
-{
- qatomic_set__nocheck(&s->value, value);
-}
-
-static inline void stat64_add(Stat64 *s, uint64_t value)
-{
- qatomic_add(&s->value, value);
-}
-
-static inline void stat64_min(Stat64 *s, uint64_t value)
-{
- uint64_t orig = qatomic_read__nocheck(&s->value);
- while (orig > value) {
- orig = qatomic_cmpxchg__nocheck(&s->value, orig, value);
- }
-}
-
-static inline void stat64_max(Stat64 *s, uint64_t value)
-{
- uint64_t orig = qatomic_read__nocheck(&s->value);
- while (orig < value) {
- orig = qatomic_cmpxchg__nocheck(&s->value, orig, value);
- }
-}
-#else
-uint64_t stat64_get(const Stat64 *s);
-void stat64_set(Stat64 *s, uint64_t value);
-bool stat64_min_slow(Stat64 *s, uint64_t value);
-bool stat64_max_slow(Stat64 *s, uint64_t value);
-bool stat64_add32_carry(Stat64 *s, uint32_t low, uint32_t high);
-
-static inline void stat64_init(Stat64 *s, uint64_t value)
-{
- /* This is not guaranteed to be atomic! */
- *s = (Stat64) { .low = value, .high = value >> 32, .lock = 0 };
-}
-
-static inline void stat64_add(Stat64 *s, uint64_t value)
-{
- uint32_t low, high;
- high = value >> 32;
- low = (uint32_t) value;
- if (!low) {
- if (high) {
- qatomic_add(&s->high, high);
- }
- return;
- }
-
- for (;;) {
- uint32_t orig = s->low;
- uint32_t result = orig + low;
- uint32_t old;
-
- if (result < low || high) {
- /* If the high part is affected, take the lock. */
- if (stat64_add32_carry(s, low, high)) {
- return;
- }
- continue;
- }
-
- /* No carry, try with a 32-bit cmpxchg. The result is independent of
- * the high 32 bits, so it can race just fine with stat64_add32_carry
- * and even stat64_get!
- */
- old = qatomic_cmpxchg(&s->low, orig, result);
- if (orig == old) {
- return;
- }
- }
-}
-
-static inline void stat64_min(Stat64 *s, uint64_t value)
-{
- uint32_t low, high;
- uint32_t orig_low, orig_high;
-
- high = value >> 32;
- low = (uint32_t) value;
- do {
- orig_high = qatomic_read(&s->high);
- if (orig_high < high) {
- return;
- }
-
- if (orig_high == high) {
- /* High 32 bits are equal. Read low after high, otherwise we
- * can get a false positive (e.g. 0x1235,0x0000 changes to
- * 0x1234,0x8000 and we read it as 0x1234,0x0000). Pairs with
- * the write barrier in stat64_min_slow.
- */
- smp_rmb();
- orig_low = qatomic_read(&s->low);
- if (orig_low <= low) {
- return;
- }
-
- /* See if we were lucky and a writer raced against us. The
- * barrier is theoretically unnecessary, but if we remove it
- * we may miss being lucky.
- */
- smp_rmb();
- orig_high = qatomic_read(&s->high);
- if (orig_high < high) {
- return;
- }
- }
-
- /* If the value changes in any way, we have to take the lock. */
- } while (!stat64_min_slow(s, value));
-}
-
-static inline void stat64_max(Stat64 *s, uint64_t value)
-{
- uint32_t low, high;
- uint32_t orig_low, orig_high;
-
- high = value >> 32;
- low = (uint32_t) value;
- do {
- orig_high = qatomic_read(&s->high);
- if (orig_high > high) {
- return;
- }
-
- if (orig_high == high) {
- /* High 32 bits are equal. Read low after high, otherwise we
- * can get a false positive (e.g. 0x1234,0x8000 changes to
- * 0x1235,0x0000 and we read it as 0x1235,0x8000). Pairs with
- * the write barrier in stat64_max_slow.
- */
- smp_rmb();
- orig_low = qatomic_read(&s->low);
- if (orig_low >= low) {
- return;
- }
-
- /* See if we were lucky and a writer raced against us. The
- * barrier is theoretically unnecessary, but if we remove it
- * we may miss being lucky.
- */
- smp_rmb();
- orig_high = qatomic_read(&s->high);
- if (orig_high > high) {
- return;
- }
- }
-
- /* If the value changes in any way, we have to take the lock. */
- } while (!stat64_max_slow(s, value));
-}
-
-#endif
-
-#endif
diff --git a/util/stats64.c b/util/stats64.c
deleted file mode 100644
index 09736014ec..0000000000
--- a/util/stats64.c
+++ /dev/null
@@ -1,148 +0,0 @@
-/*
- * Atomic operations on 64-bit quantities.
- *
- * Copyright (C) 2017 Red Hat, Inc.
- *
- * Author: Paolo Bonzini <pbonzini@redhat.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- */
-
-#include "qemu/osdep.h"
-#include "qemu/atomic.h"
-#include "qemu/stats64.h"
-#include "qemu/processor.h"
-
-#ifndef CONFIG_ATOMIC64
-static inline void stat64_rdlock(Stat64 *s)
-{
- /* Keep out incoming writers to avoid them starving us. */
- qatomic_add(&s->lock, 2);
-
- /* If there is a concurrent writer, wait for it. */
- while (qatomic_read(&s->lock) & 1) {
- cpu_relax();
- }
-}
-
-static inline void stat64_rdunlock(Stat64 *s)
-{
- qatomic_sub(&s->lock, 2);
-}
-
-static inline bool stat64_wrtrylock(Stat64 *s)
-{
- return qatomic_cmpxchg(&s->lock, 0, 1) == 0;
-}
-
-static inline void stat64_wrunlock(Stat64 *s)
-{
- qatomic_dec(&s->lock);
-}
-
-uint64_t stat64_get(const Stat64 *s)
-{
- uint32_t high, low;
-
- stat64_rdlock((Stat64 *)s);
-
- /* 64-bit writes always take the lock, so we can read in
- * any order.
- */
- high = qatomic_read(&s->high);
- low = qatomic_read(&s->low);
- stat64_rdunlock((Stat64 *)s);
-
- return ((uint64_t)high << 32) | low;
-}
-
-void stat64_set(Stat64 *s, uint64_t val)
-{
- while (!stat64_wrtrylock(s)) {
- cpu_relax();
- }
-
- qatomic_set(&s->high, val >> 32);
- qatomic_set(&s->low, val);
- stat64_wrunlock(s);
-}
-
-bool stat64_add32_carry(Stat64 *s, uint32_t low, uint32_t high)
-{
- uint32_t old;
-
- if (!stat64_wrtrylock(s)) {
- cpu_relax();
- return false;
- }
-
- /* 64-bit reads always take the lock, so they don't care about the
- * order of our update. By updating s->low first, we can check
- * whether we have to carry into s->high.
- */
- old = qatomic_fetch_add(&s->low, low);
- high += (old + low) < old;
- qatomic_add(&s->high, high);
- stat64_wrunlock(s);
- return true;
-}
-
-bool stat64_min_slow(Stat64 *s, uint64_t value)
-{
- uint32_t high, low;
- uint64_t orig;
-
- if (!stat64_wrtrylock(s)) {
- cpu_relax();
- return false;
- }
-
- high = qatomic_read(&s->high);
- low = qatomic_read(&s->low);
-
- orig = ((uint64_t)high << 32) | low;
- if (value < orig) {
- /* We have to set low before high, just like stat64_min reads
- * high before low. The value may become higher temporarily, but
- * stat64_get does not notice (it takes the lock) and the only ill
- * effect on stat64_min is that the slow path may be triggered
- * unnecessarily.
- */
- qatomic_set(&s->low, (uint32_t)value);
- smp_wmb();
- qatomic_set(&s->high, value >> 32);
- }
- stat64_wrunlock(s);
- return true;
-}
-
-bool stat64_max_slow(Stat64 *s, uint64_t value)
-{
- uint32_t high, low;
- uint64_t orig;
-
- if (!stat64_wrtrylock(s)) {
- cpu_relax();
- return false;
- }
-
- high = qatomic_read(&s->high);
- low = qatomic_read(&s->low);
-
- orig = ((uint64_t)high << 32) | low;
- if (value > orig) {
- /* We have to set low before high, just like stat64_max reads
- * high before low. The value may become lower temporarily, but
- * stat64_get does not notice (it takes the lock) and the only ill
- * effect on stat64_max is that the slow path may be triggered
- * unnecessarily.
- */
- qatomic_set(&s->low, (uint32_t)value);
- smp_wmb();
- qatomic_set(&s->high, value >> 32);
- }
- stat64_wrunlock(s);
- return true;
-}
-#endif
diff --git a/util/meson.build b/util/meson.build
index 35029380a3..d7d6b213f6 100644
--- a/util/meson.build
+++ b/util/meson.build
@@ -59,7 +59,6 @@ util_ss.add(files('qht.c'))
util_ss.add(files('qsp.c'))
util_ss.add(files('range.c'))
util_ss.add(files('reserved-region.c'))
-util_ss.add(files('stats64.c'))
util_ss.add(files('systemd.c'))
util_ss.add(files('transactions.c'))
util_ss.add(files('guest-random.c'))
--
2.43.0