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 A42FA192D0F; Wed, 13 Mar 2024 17:02:58 +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=1710349378; cv=none; b=nkTIjJtJyEE93v7ssIGcka1QjNbElu2HmFXyb1X+ZmPMpttJcOmNo+jeBiFTZjHn8R/SbJh7rm+w7/F6kZ6cRpGUC5GGKWUB3wUFsxi269L48Ve2irmtD3ZmHyTI18jipk7X+VoDqq37DPsFuGq6ukdr2cPbqTp7Xja228utz8Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710349378; c=relaxed/simple; bh=+czO4uXifLZKrI1l9b4XlYCb9idK67Z0Gjf3er/VpVA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c9ZFBGY+zIV/uAjLGTClK2c/NsSvYD/tVbVFvh4DZKPJg7sNxw/I92BosPw5RgtrumYxbCgUKBdIZSx4uNKcK87j41BQGtyHmF4Uw4RakBkDC2bZM2K3XgsV/sRTDCldFKLZvJT3/YEO431gnv6sxFc1FpTRDJ017ir3/92lIeI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=S2CPLAyr; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="S2CPLAyr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A15BEC43399; Wed, 13 Mar 2024 17:02:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710349378; bh=+czO4uXifLZKrI1l9b4XlYCb9idK67Z0Gjf3er/VpVA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S2CPLAyr3Wir1AF64U7YCQP+ov0XLGJpTxwgMH96Xm9jV2y8uEhQRihnCG5uTZGs/ 6RPMkaYd6GgegMEYdx7tB1U3tRrHhi+gpIpharZR7692rmEuCIKOm6BGSv9HVe57dO ConF5QoPIK29kwC8iYnu9X/KyMOLgMXHt3a3mBjmEaYZ4wv3bLPG0Dh3GCgmjEL3CS cY7zXmKwJIAfrKzcF++G+ht7Erv4DtLFz0dfKlct7AwHJ8z9WDN47AxvPea47ttHSc rl2VqqHbY5mF0KI47nYNi7/YFIUVRiGoY988gQS+qxL+dnfuLMe5p635IKzRhcrOXk UNxLsiDUKMI/w== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Oleg Nesterov , Dylan Hatch , "Eric W . Biederman" , Andrew Morton , Sasha Levin Subject: [PATCH 5.4 40/51] getrusage: move thread_group_cputime_adjusted() outside of lock_task_sighand() Date: Wed, 13 Mar 2024 13:02:01 -0400 Message-ID: <20240313170212.616443-41-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240313170212.616443-1-sashal@kernel.org> References: <20240313170212.616443-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.4.272-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.4.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.4.272-rc1 X-KernelTest-Deadline: 2024-03-15T17:02+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit From: Oleg Nesterov [ Upstream commit daa694e4137571b4ebec330f9a9b4d54aa8b8089 ] Patch series "getrusage: use sig->stats_lock", v2. This patch (of 2): 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. This is also preparation for the next patch which changes getrusage() to use stats_lock instead of siglock, thread_group_cputime() takes the same lock. With the current implementation recursive read_seqbegin_or_lock() is fine, thread_group_cputime() can't enter the slow mode if the caller holds stats_lock, yet this looks more safe and better performance-wise. Link: https://lkml.kernel.org/r/20240122155023.GA26169@redhat.com Link: https://lkml.kernel.org/r/20240122155050.GA26205@redhat.com Signed-off-by: Oleg Nesterov Reported-by: Dylan Hatch Tested-by: Dylan Hatch Cc: Eric W. Biederman Cc: Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- kernel/sys.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/kernel/sys.c b/kernel/sys.c index 76b601d56c027..b53ad9e50e465 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1711,17 +1711,19 @@ void getrusage(struct task_struct *p, int who, struct rusage *r) struct task_struct *t; unsigned long flags; u64 tgutime, tgstime, utime, stime; - unsigned long maxrss = 0; + unsigned long maxrss; + struct mm_struct *mm; struct signal_struct *sig = p->signal; - memset((char *)r, 0, sizeof (*r)); + memset(r, 0, sizeof(*r)); utime = stime = 0; + maxrss = 0; if (who == RUSAGE_THREAD) { task_cputime_adjusted(current, &utime, &stime); accumulate_thread_rusage(p, r); maxrss = sig->maxrss; - goto out; + goto out_thread; } if (!lock_task_sighand(p, &flags)) @@ -1745,9 +1747,6 @@ void getrusage(struct task_struct *p, int who, struct rusage *r) /* fall through */ case RUSAGE_SELF: - thread_group_cputime_adjusted(p, &tgutime, &tgstime); - utime += tgutime; - stime += tgstime; r->ru_nvcsw += sig->nvcsw; r->ru_nivcsw += sig->nivcsw; r->ru_minflt += sig->min_flt; @@ -1767,19 +1766,24 @@ void getrusage(struct task_struct *p, int who, struct rusage *r) } unlock_task_sighand(p, &flags); -out: - r->ru_utime = ns_to_kernel_old_timeval(utime); - r->ru_stime = ns_to_kernel_old_timeval(stime); + if (who == RUSAGE_CHILDREN) + goto out_children; - if (who != RUSAGE_CHILDREN) { - struct mm_struct *mm = get_task_mm(p); + thread_group_cputime_adjusted(p, &tgutime, &tgstime); + utime += tgutime; + stime += tgstime; - if (mm) { - setmax_mm_hiwater_rss(&maxrss, mm); - mmput(mm); - } +out_thread: + mm = get_task_mm(p); + if (mm) { + setmax_mm_hiwater_rss(&maxrss, mm); + mmput(mm); } + +out_children: r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ + r->ru_utime = ns_to_kernel_old_timeval(utime); + r->ru_stime = ns_to_kernel_old_timeval(stime); } SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) -- 2.43.0