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envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::62f; envelope-from=paolo.bonzini@gmail.com; helo=mail-ej1-x62f.google.com X-Spam_score_int: -14 X-Spam_score: -1.5 X-Spam_bar: - X-Spam_report: (-1.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: eesposit@redhat.com, stefanha@redhat.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Right now, rate limiting is protected by the AioContext mutex, which is taken for example both by the block jobs and by qmp_block_job_set_speed (via find_block_job). We would like to remove the dependency of block layer code on the AioContext mutex, since most drivers and the core I/O code are already not relying on it. However, there is no existing lock that can easily be taken by both ratelimit_set_speed and ratelimit_calculate_delay, especially because the latter might run in coroutine context (and therefore under a CoMutex) but the former will not. Since concurrent calls to ratelimit_calculate_delay are not possible, one idea could be to use a seqlock to get a snapshot of slice_ns and slice_quota. But for now keep it simple, and just add a mutex to the RateLimit struct; block jobs are generally not performance critical to the point of optimizing the clock cycles spent in synchronization. This also requires the introduction of init/destroy functions, so add them to the two users of ratelimit.h. Signed-off-by: Paolo Bonzini Reviewed-by: Emanuele Giuseppe Esposito Reviewed-by: Stefan Hajnoczi Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/block-copy.c | 2 ++ blockjob.c | 3 +++ include/qemu/ratelimit.h | 14 ++++++++++++++ 3 files changed, 19 insertions(+) diff --git a/block/block-copy.c b/block/block-copy.c index 39ae481c8b..9b4af00614 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -230,6 +230,7 @@ void block_copy_state_free(BlockCopyState *s) return; } =20 + ratelimit_destroy(&s->rate_limit); bdrv_release_dirty_bitmap(s->copy_bitmap); shres_destroy(s->mem); g_free(s); @@ -289,6 +290,7 @@ BlockCopyState *block_copy_state_new(BdrvChild *source,= BdrvChild *target, s->copy_size =3D MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER); } =20 + ratelimit_init(&s->rate_limit); QLIST_INIT(&s->tasks); QLIST_INIT(&s->calls); =20 diff --git a/blockjob.c b/blockjob.c index 207e8c7fd9..46f15befe8 100644 --- a/blockjob.c +++ b/blockjob.c @@ -87,6 +87,7 @@ void block_job_free(Job *job) =20 block_job_remove_all_bdrv(bjob); blk_unref(bjob->blk); + ratelimit_destroy(&bjob->limit); error_free(bjob->blocker); } =20 @@ -435,6 +436,8 @@ void *block_job_create(const char *job_id, const BlockJ= obDriver *driver, assert(job->job.driver->free =3D=3D &block_job_free); assert(job->job.driver->user_resume =3D=3D &block_job_user_resume); =20 + ratelimit_init(&job->limit); + job->blk =3D blk; =20 job->finalize_cancelled_notifier.notify =3D block_job_event_cancelled; diff --git a/include/qemu/ratelimit.h b/include/qemu/ratelimit.h index 01da8d63f1..003ea6d5a3 100644 --- a/include/qemu/ratelimit.h +++ b/include/qemu/ratelimit.h @@ -14,9 +14,11 @@ #ifndef QEMU_RATELIMIT_H #define QEMU_RATELIMIT_H =20 +#include "qemu/lockable.h" #include "qemu/timer.h" =20 typedef struct { + QemuMutex lock; int64_t slice_start_time; int64_t slice_end_time; uint64_t slice_quota; @@ -40,6 +42,7 @@ static inline int64_t ratelimit_calculate_delay(RateLimit= *limit, uint64_t n) int64_t now =3D qemu_clock_get_ns(QEMU_CLOCK_REALTIME); double delay_slices; =20 + QEMU_LOCK_GUARD(&limit->lock); assert(limit->slice_quota && limit->slice_ns); =20 if (limit->slice_end_time < now) { @@ -65,9 +68,20 @@ static inline int64_t ratelimit_calculate_delay(RateLimi= t *limit, uint64_t n) return limit->slice_end_time - now; } =20 +static inline void ratelimit_init(RateLimit *limit) +{ + qemu_mutex_init(&limit->lock); +} + +static inline void ratelimit_destroy(RateLimit *limit) +{ + qemu_mutex_destroy(&limit->lock); +} + static inline void ratelimit_set_speed(RateLimit *limit, uint64_t speed, uint64_t slice_ns) { + QEMU_LOCK_GUARD(&limit->lock); limit->slice_ns =3D slice_ns; limit->slice_quota =3D MAX(((double)speed * slice_ns) / 1000000000ULL,= 1); } --=20 2.30.1