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| author | Emilio G. Cota | 2018-08-19 11:13:35 +0200 |
|---|---|---|
| committer | Paolo Bonzini | 2018-08-23 18:46:25 +0200 |
| commit | 068a5ea02f62853116788a2c42d8851a94bb7567 (patch) | |
| tree | 0e7c635241a440b1aeee6dd853077fad928a40d4 /include/qom | |
| parent | spapr: do not use CPU_FOREACH_REVERSE (diff) | |
| download | qemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.gz qemu-068a5ea02f62853116788a2c42d8851a94bb7567.tar.xz qemu-068a5ea02f62853116788a2c42d8851a94bb7567.zip | |
qom: convert the CPU list to RCU
Iterating over the list without using atomics is undefined behaviour,
since the list can be modified concurrently by other threads (e.g.
every time a new thread is created in user-mode).
Fix it by implementing the CPU list as an RCU QTAILQ. This requires
a little bit of extra work to traverse list in reverse order (see
previous patch), but other than that the conversion is trivial.
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20180819091335.22863-12-cota@braap.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include/qom')
| -rw-r--r-- | include/qom/cpu.h | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/include/qom/cpu.h b/include/qom/cpu.h index ecf6ed556a..dc130cd307 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -26,6 +26,7 @@ #include "exec/memattrs.h" #include "qapi/qapi-types-run-state.h" #include "qemu/bitmap.h" +#include "qemu/rcu_queue.h" #include "qemu/queue.h" #include "qemu/thread.h" @@ -442,13 +443,11 @@ struct CPUState { QTAILQ_HEAD(CPUTailQ, CPUState); extern struct CPUTailQ cpus; -#define CPU_NEXT(cpu) QTAILQ_NEXT(cpu, node) -#define CPU_FOREACH(cpu) QTAILQ_FOREACH(cpu, &cpus, node) +#define first_cpu QTAILQ_FIRST_RCU(&cpus) +#define CPU_NEXT(cpu) QTAILQ_NEXT_RCU(cpu, node) +#define CPU_FOREACH(cpu) QTAILQ_FOREACH_RCU(cpu, &cpus, node) #define CPU_FOREACH_SAFE(cpu, next_cpu) \ - QTAILQ_FOREACH_SAFE(cpu, &cpus, node, next_cpu) -#define CPU_FOREACH_REVERSE(cpu) \ - QTAILQ_FOREACH_REVERSE(cpu, &cpus, CPUTailQ, node) -#define first_cpu QTAILQ_FIRST(&cpus) + QTAILQ_FOREACH_SAFE_RCU(cpu, &cpus, node, next_cpu) extern __thread CPUState *current_cpu; |