From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66AA5C4167B for ; Wed, 6 Dec 2023 08:59:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377114AbjLFI7u (ORCPT ); Wed, 6 Dec 2023 03:59:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53408 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbjLFI7t (ORCPT ); Wed, 6 Dec 2023 03:59:49 -0500 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A0A91736 for ; Wed, 6 Dec 2023 00:59:49 -0800 (PST) Received: by verein.lst.de (Postfix, from userid 2407) id 161D4227A8E; Wed, 6 Dec 2023 09:59:46 +0100 (CET) Date: Wed, 6 Dec 2023 09:59:45 +0100 From: Christoph Hellwig To: Daniel Wagner Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, Keith Busch , Christoph Hellwig , Sagi Grimberg , Hannes Reinecke Subject: Re: [PATCH v3 4/4] nvme: add csi, ms and nuse to sysfs Message-ID: <20231206085945.GC24484@lst.de> References: <20231206081244.32733-1-dwagner@suse.de> <20231206081244.32733-5-dwagner@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231206081244.32733-5-dwagner@suse.de> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 06, 2023 at 09:12:44AM +0100, Daniel Wagner wrote: > libnvme is using the sysfs for enumarating the nvme resources. Though > there are few missing attritbutes in the sysfs. For these libnvme issues > commands during discovering. > > As the kernel already knows all these attributes and we would like to > avoid libnvme to issue commands all the time, expose these missing > attributes. > > The nuse value is updated on request because the nuse is a volatile > value. Since any user can read the sysfs attribute, a very simple rate > limit is added (update max every 5 seconds). A more sophisticated update > strategy can be added later if there is actually a need for it. > > Signed-off-by: Daniel Wagner > --- > drivers/nvme/host/core.c | 28 ++++++++++++++++++++++++++++ > drivers/nvme/host/nvme.h | 2 ++ > drivers/nvme/host/sysfs.c | 31 +++++++++++++++++++++++++++++++ > 3 files changed, 61 insertions(+) > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index caa52c2f57c8..e7dd64ee1653 100644 > --- a/drivers/nvme/host/core.c > +++ b/drivers/nvme/host/core.c > @@ -1663,6 +1663,33 @@ static void nvme_ns_release(struct nvme_ns *ns) > nvme_put_ns(ns); > } > > +int nvme_ns_update_nuse(struct nvme_ns_head *head) > +{ > + static DEFINE_RATELIMIT_STATE(_rs, 5 * HZ, 1); > + struct nvme_id_ns *id; > + struct nvme_ns *ns; > + int srcu_idx, ret = -EWOULDBLOCK; > + > + if (__ratelimit(&_rs)) > + return 0; Can you add a comment on the ratelimiting here? > + > + srcu_idx = srcu_read_lock(&head->srcu); > + ns = nvme_find_path(head); > + if (!ns) > + goto out_unlock; > + > + ret = nvme_identify_ns(ns->ctrl, head->ns_id, &id); > + if (ret) > + goto out_unlock; > + > + head->nuse = le64_to_cpu(id->nuse); This looks like the wrong thing to do for the non-multipath nodes, which should be able to go straight to the ns. I'd move this to sysfs.c, and then do a similar trick to say nvme_send_pr_command to directly use the ns for the non-multipath nodes, and do what you're doing here for the multipath nodes. > static struct attribute *nvme_ns_id_attrs[] = { And I duess the _id is not correct now, I'd just drop it.