From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1ABE72C3749; Mon, 27 Oct 2025 19:27:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761593252; cv=none; b=VoAzFwyHjYkQW1eeMQYk+M87bfUn5mbVhnoWovepTw04x6RfBMKIvJyBUoSt0thY7XsAKTAirQNzKIUyXYxgAgJv0+7/r83uv03YTwa0HxuirSzsNYmNOcz034LQ7wAXuYgHpPpXGz5pPC/IAb4Ydz68bPiLrVCr+3p5Q/RwN1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761593252; c=relaxed/simple; bh=zrE3bH5ZWtkgZY71rSyP8nHcEV82Gz61IBI7EmQC988=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=IyXvwAVcGpM2ZJBBhc133KXn+SKn1LcnPdf9YLD7AxcT+bHM5qO+qiJATOl0OxcTKxL2d43ttzbxuHSm3114DGQlinEFhGrtFOgr/lMzv7xiLcmGXmLwbVTzx1mj2DplG0n4gEgada6DCwoUAcNGxSkygXc+CevMBjpQo9HNnTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HML3bz+L; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="HML3bz+L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F6F1C4CEF1; Mon, 27 Oct 2025 19:27:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1761593252; bh=zrE3bH5ZWtkgZY71rSyP8nHcEV82Gz61IBI7EmQC988=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HML3bz+L4W9e9Y15WeW1rLl2RVgS37XnjXQtQ2Lfa1nt5gYmZRAxeEnLzfCGnU9tq uJ0v0fn5pids+3KuYL7Pb9cIAULcn4VUfZOij5QNFAZkJC6dm00C/rT83l18COifdF cYVwfbcseMbr3IlFncUN4ZQ1thyqUgyTVNVmrlFQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gabriel Krisman Bertazi , Jens Axboe Subject: [PATCH 6.17 069/184] io_uring/sqpoll: switch away from getrusage() for CPU accounting Date: Mon, 27 Oct 2025 19:35:51 +0100 Message-ID: <20251027183516.749654076@linuxfoundation.org> X-Mailer: git-send-email 2.51.1 In-Reply-To: <20251027183514.934710872@linuxfoundation.org> References: <20251027183514.934710872@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe commit 8ac9b0d33e5c0a995338ee5f25fe1b6ff7d97f65 upstream. getrusage() does a lot more than what the SQPOLL accounting needs, the latter only cares about (and uses) the stime. Rather than do a full RUSAGE_SELF summation, just query the used stime instead. Cc: stable@vger.kernel.org Fixes: 3fcb9d17206e ("io_uring/sqpoll: statistics of the true utilization of sq threads") Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/fdinfo.c | 8 ++++---- io_uring/sqpoll.c | 32 ++++++++++++++++++-------------- io_uring/sqpoll.h | 1 + 3 files changed, 23 insertions(+), 18 deletions(-) --- a/io_uring/fdinfo.c +++ b/io_uring/fdinfo.c @@ -59,7 +59,6 @@ static void __io_uring_show_fdinfo(struc { struct io_overflow_cqe *ocqe; struct io_rings *r = ctx->rings; - struct rusage sq_usage; unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1; unsigned int sq_head = READ_ONCE(r->sq.head); unsigned int sq_tail = READ_ONCE(r->sq.tail); @@ -150,14 +149,15 @@ static void __io_uring_show_fdinfo(struc * thread termination. */ if (tsk) { + u64 usec; + get_task_struct(tsk); rcu_read_unlock(); - getrusage(tsk, RUSAGE_SELF, &sq_usage); + usec = io_sq_cpu_usec(tsk); put_task_struct(tsk); sq_pid = sq->task_pid; sq_cpu = sq->sq_cpu; - sq_total_time = (sq_usage.ru_stime.tv_sec * 1000000 - + sq_usage.ru_stime.tv_usec); + sq_total_time = usec; sq_work_time = sq->work_time; } else { rcu_read_unlock(); --- a/io_uring/sqpoll.c +++ b/io_uring/sqpoll.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -169,6 +170,20 @@ static inline bool io_sqd_events_pending return READ_ONCE(sqd->state); } +u64 io_sq_cpu_usec(struct task_struct *tsk) +{ + u64 utime, stime; + + task_cputime_adjusted(tsk, &utime, &stime); + do_div(stime, 1000); + return stime; +} + +static void io_sq_update_worktime(struct io_sq_data *sqd, u64 usec) +{ + sqd->work_time += io_sq_cpu_usec(current) - usec; +} + static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) { unsigned int to_submit; @@ -255,26 +270,15 @@ static bool io_sq_tw_pending(struct llis return retry_list || !llist_empty(&tctx->task_list); } -static void io_sq_update_worktime(struct io_sq_data *sqd, struct rusage *start) -{ - struct rusage end; - - getrusage(current, RUSAGE_SELF, &end); - end.ru_stime.tv_sec -= start->ru_stime.tv_sec; - end.ru_stime.tv_usec -= start->ru_stime.tv_usec; - - sqd->work_time += end.ru_stime.tv_usec + end.ru_stime.tv_sec * 1000000; -} - static int io_sq_thread(void *data) { struct llist_node *retry_list = NULL; struct io_sq_data *sqd = data; struct io_ring_ctx *ctx; - struct rusage start; unsigned long timeout = 0; char buf[TASK_COMM_LEN] = {}; DEFINE_WAIT(wait); + u64 start; /* offload context creation failed, just exit */ if (!current->io_uring) { @@ -317,7 +321,7 @@ static int io_sq_thread(void *data) } cap_entries = !list_is_singular(&sqd->ctx_list); - getrusage(current, RUSAGE_SELF, &start); + start = io_sq_cpu_usec(current); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { int ret = __io_sq_thread(ctx, cap_entries); @@ -333,7 +337,7 @@ static int io_sq_thread(void *data) if (sqt_spin || !time_after(jiffies, timeout)) { if (sqt_spin) { - io_sq_update_worktime(sqd, &start); + io_sq_update_worktime(sqd, start); timeout = jiffies + sqd->sq_thread_idle; } if (unlikely(need_resched())) { --- a/io_uring/sqpoll.h +++ b/io_uring/sqpoll.h @@ -29,6 +29,7 @@ void io_sq_thread_unpark(struct io_sq_da void io_put_sq_data(struct io_sq_data *sqd); void io_sqpoll_wait_sq(struct io_ring_ctx *ctx); int io_sqpoll_wq_cpu_affinity(struct io_ring_ctx *ctx, cpumask_var_t mask); +u64 io_sq_cpu_usec(struct task_struct *tsk); static inline struct task_struct *sqpoll_task_locked(struct io_sq_data *sqd) {