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 16EAF1A28D for ; Thu, 27 Mar 2025 17:19:05 +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=1743095945; cv=none; b=sHpYLD7AQF/OJYTY5VKnjrt5uZSDDRiBIPyjGgxW+tdtuDiFvmn0pluGsMtzLoK8OebKwWsB3HWLebrA7yE95c30c0PHBcmscURj/whKHJ3OpshrbJQpesjcPU47vi21UhGK/leZhYRaxQ7pEcGj+o8Dcwyl7EaeUL8IOMY7kfA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743095945; c=relaxed/simple; bh=obhnZ94S9tmTE49IzNlDGIP5YjR1w9PDoJHTDx1VrWY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o6rJEGQHIPsNuYwCkNw4GUd8WRvDSULX5VY81rDr7jWSB7G9x2+0f0lmAq1UXkgJVRXEE30oNShHJrpYKK9PjaxbnJ/OSuPwN6Ftj7ZjIeG/wukire1OicfS9HtG84gGFdRWwzIm7KNPr8jLtw1MBAElu6/nclDQxgpBUNJT7gg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HLYgfl2V; 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="HLYgfl2V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D00FBC4CEDD; Thu, 27 Mar 2025 17:19:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743095945; bh=obhnZ94S9tmTE49IzNlDGIP5YjR1w9PDoJHTDx1VrWY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HLYgfl2VHleXyg0r3nySfB4zyxiAXgX85cfy1bi/FAAIfMqA7gGNhtQ5Rrz8ZdmQz /jyqKWZyTm+gwnVwJBKxAaw6J7wPeKJrFTcrhtQV/MhIH31/xcrZuHvoPbA1fJPqpV HflKOVP0Q5kpDNLN4FTkHjGB4ky95c1VxJkbtC6RswiAAuOsVSLU5nzMRKpmpGuCUv 3zz9vtjOtf/T0/3eXtCTnRFr+dDe8xM4DJ45ainh2GLXI/xQZt07isJpuO8gqZcvUS QDz57jiMkabDdgvTQyGi2TtoDYYA2VJF7toa3kah5zDerll9u4u/57kyJPlLRDtiAY FqzOwcsKtrg2g== Date: Thu, 27 Mar 2025 07:19:03 -1000 From: Tejun Heo To: Andrea Righi Cc: David Vernet , Changwoo Min , Joel Fernandes , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched_ext: Fix missing rq lock in scx_bpf_cpuperf_set() Message-ID: References: <20250325140021.73570-1-arighi@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hello, On Thu, Mar 27, 2025 at 06:15:09PM +0100, Andrea Righi wrote: > > If we don't want to do locked rq tracking, we can always use > > schedule_deferred() when any rq is locked too. That's a bit more expensive > > tho. > > Yeah, I'm a bit worried that locked rq tracking might introduce overhead to > all the scx callbacks, just to address this issue. All operaitons are already wrapped with SCX_CALL_OP() and updating per-cpu state (kf flags). It's unlikely that another percpu variable update is going to be noticeable. Thanks. -- tejun