From nobody Wed Dec 24 23:33:27 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 9B42E657B2 for ; Tue, 23 Jan 2024 15:35:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706024117; cv=none; b=Qqz4j96+YMQpwx2XJvNV2n8h7yUdjXBHOYpCbNRnXOUrxMFZutw5t6YmmDYXn94hJhs/wf7H9U7YNZCFd1nojV3DqafZ9UAcKUlcyNVFdXdFdzzutlNpXlqaIdsmWfqfU3HCwgS0ecu49eEvuHdTy1CaelIWa6seUKjI0UbIj2Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706024117; c=relaxed/simple; bh=D9S/w+5o+A62Nxx/ISEz51lECzS059pBiYjXyW/CbrY=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=hLck8Gz4iKCBs4KDaSI6HY1fAttyERu39oSnxG7OFqI0Pfz8eVIWRSQMfLK+cOthvL/34ZkF3S+J7zH31fvk7rXxxybf/15YmM5rhR//a/Q/A7V0alH8mCJX3RjcNetclEEDoQRinPMEvyw9caH1XAUbDXxCbETqSzI4o8lEy4E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=MGJ0vJKf; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MGJ0vJKf" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706024114; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to; bh=bIcROdxOGKA/fk6m4Nxqn1gTa+sWPdKk6gCIL7a7N7s=; b=MGJ0vJKfGNKt5plbWSJ+UfxBy5khqHkF6eqhFkijFpJ6UynryjPBAKjKVZbeGVZ870r14o x7zMu4cehtcPs4EVIezg/JL09t8OJhXvwBngiKS3xEc3wK/AHIC64A7rDw35zwQ7w+vJQg 9GHDuN5ttHYGapZ5JpjYXMEjoxS2xps= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-201-Eh1mlGpsPxWje1pyXNOMIA-1; Tue, 23 Jan 2024 10:35:10 -0500 X-MC-Unique: Eh1mlGpsPxWje1pyXNOMIA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 089FD185A785; Tue, 23 Jan 2024 15:35:10 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.197]) by smtp.corp.redhat.com (Postfix) with SMTP id D83BD40C1430; Tue, 23 Jan 2024 15:35:08 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Tue, 23 Jan 2024 16:33:56 +0100 (CET) Date: Tue, 23 Jan 2024 16:33:55 +0100 From: Oleg Nesterov To: Andrew Morton Cc: "Eric W. Biederman" , Dylan Hatch , linux-kernel@vger.kernel.org Subject: [PATCH 1/3] fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand() Message-ID: <20240123153355.GA21854@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240123153313.GA21832@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" thread_group_cputime() does its own locking, we can safely shift thread_group_cputime_adjusted() which does another for_each_thread loop outside of ->siglock protected section. Not only this removes for_each_thread() from the critical section with irqs disabled, this removes another case when stats_lock is taken with siglock held. We want to remove this dependency, then we can change the users of stats_lock to not disable irqs. Signed-off-by: Oleg Nesterov --- fs/proc/array.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index ff08a8957552..45ba91863808 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -511,7 +511,7 @@ static int do_task_stat(struct seq_file *m, struct pid_= namespace *ns, =20 sigemptyset(&sigign); sigemptyset(&sigcatch); - cutime =3D cstime =3D utime =3D stime =3D 0; + cutime =3D cstime =3D 0; cgtime =3D gtime =3D 0; =20 if (lock_task_sighand(task, &flags)) { @@ -546,7 +546,6 @@ static int do_task_stat(struct seq_file *m, struct pid_= namespace *ns, =20 min_flt +=3D sig->min_flt; maj_flt +=3D sig->maj_flt; - thread_group_cputime_adjusted(task, &utime, &stime); gtime +=3D sig->gtime; =20 if (sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_STOP_STOPPED)) @@ -562,10 +561,13 @@ static int do_task_stat(struct seq_file *m, struct pi= d_namespace *ns, =20 if (permitted && (!whole || num_threads < 2)) wchan =3D !task_is_running(task); - if (!whole) { + + if (whole) { + thread_group_cputime_adjusted(task, &utime, &stime); + } else { + task_cputime_adjusted(task, &utime, &stime); min_flt =3D task->min_flt; maj_flt =3D task->maj_flt; - task_cputime_adjusted(task, &utime, &stime); gtime =3D task_gtime(task); } =20 --=20 2.25.1.362.g51ebf55