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 8B120C25B4E for ; Fri, 20 Jan 2023 09:01:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbjATJA7 (ORCPT ); Fri, 20 Jan 2023 04:00:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229489AbjATJA6 (ORCPT ); Fri, 20 Jan 2023 04:00:58 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D06C540DF; Fri, 20 Jan 2023 01:00:56 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 83F31228D8; Fri, 20 Jan 2023 09:00:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1674205255; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bqzOV/Iv6aZGmhpj9C+RqWOJmqu+Ctue2fjtEzP4yH4=; b=velkg0L7SxjsHBOqYT+6tMAKhONYwZ3ifUwnZVFNT0JXcsFyvdoySKvCW1k7nAwD8iEWHt Ff040TOvcRxOW3pk4PH5QmxTqoQ2NxENgeMg/6McancT7UEffC6JBa+gTeQ3ypA8R1R6jP Wv3yUlFQm3vwApsY5ZoDiUsbulR62is= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1674205255; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bqzOV/Iv6aZGmhpj9C+RqWOJmqu+Ctue2fjtEzP4yH4=; b=niSXmgnKh0jSdn+019P+rsXUDASphFEl10alKXPUnPSIyW8rBNF8fokRUohcM5mD3JED/f cCVmj7+BwHW2PKDg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 0A91913251; Fri, 20 Jan 2023 09:00:54 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id yxXJOUZYymMkIwAAMHmgww (envelope-from ); Fri, 20 Jan 2023 09:00:54 +0000 Date: Fri, 20 Jan 2023 10:00:53 +0100 From: Andreas Herrmann To: Christoph Hellwig Cc: Jens Axboe , Tejun Heo , Josef Bacik , linux-block@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH 05/15] blk-cgroup: store a gendisk to throttle in struct task_struct Message-ID: References: <20230117081257.3089859-1-hch@lst.de> <20230117081257.3089859-6-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230117081257.3089859-6-hch@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jan 17, 2023 at 09:12:47AM +0100, Christoph Hellwig wrote: > Switch from a request_queue pointer and reference to a gendisk once > for the throttle information in struct task_struct. > > Move the check for the dead disk to the latest place now that is is ^^ it > unboundled from the reference grab. ^^^^^^^^^^ unbundled > > Signed-off-by: Christoph Hellwig > --- > block/blk-cgroup.c | 37 +++++++++++++++++++------------------ > include/linux/sched.h | 2 +- > kernel/fork.c | 2 +- > mm/swapfile.c | 2 +- > 4 files changed, 22 insertions(+), 21 deletions(-) Looks good to me. Feel free to add Reviewed-by: Andreas Herrmann > diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c > index f5a634ed098db0..603e911d1350db 100644 > --- a/block/blk-cgroup.c > +++ b/block/blk-cgroup.c > @@ -1334,9 +1334,9 @@ static void blkcg_bind(struct cgroup_subsys_state *root_css) > > static void blkcg_exit(struct task_struct *tsk) > { > - if (tsk->throttle_queue) > - blk_put_queue(tsk->throttle_queue); > - tsk->throttle_queue = NULL; > + if (tsk->throttle_disk) > + put_disk(tsk->throttle_disk); > + tsk->throttle_disk = NULL; > } > > struct cgroup_subsys io_cgrp_subsys = { > @@ -1778,29 +1778,32 @@ static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay) > * > * This is only called if we've been marked with set_notify_resume(). Obviously > * we can be set_notify_resume() for reasons other than blkcg throttling, so we > - * check to see if current->throttle_queue is set and if not this doesn't do > + * check to see if current->throttle_disk is set and if not this doesn't do > * anything. This should only ever be called by the resume code, it's not meant > * to be called by people willy-nilly as it will actually do the work to > * throttle the task if it is setup for throttling. > */ > void blkcg_maybe_throttle_current(void) > { > - struct request_queue *q = current->throttle_queue; > + struct gendisk *disk = current->throttle_disk; > struct blkcg *blkcg; > struct blkcg_gq *blkg; > bool use_memdelay = current->use_memdelay; > > - if (!q) > + if (!disk) > return; > > - current->throttle_queue = NULL; > + current->throttle_disk = NULL; > current->use_memdelay = false; > > + if (test_bit(GD_DEAD, &disk->state)) > + goto out_put_disk; > + > rcu_read_lock(); > blkcg = css_to_blkcg(blkcg_css()); > if (!blkcg) > goto out; > - blkg = blkg_lookup(blkcg, q); > + blkg = blkg_lookup(blkcg, disk->queue); > if (!blkg) > goto out; > if (!blkg_tryget(blkg)) > @@ -1809,11 +1812,12 @@ void blkcg_maybe_throttle_current(void) > > blkcg_maybe_throttle_blkg(blkg, use_memdelay); > blkg_put(blkg); > - blk_put_queue(q); > + put_disk(disk); > return; > out: > rcu_read_unlock(); > - blk_put_queue(q); > +out_put_disk: > + put_disk(disk); > } > > /** > @@ -1835,18 +1839,15 @@ void blkcg_maybe_throttle_current(void) > */ > void blkcg_schedule_throttle(struct gendisk *disk, bool use_memdelay) > { > - struct request_queue *q = disk->queue; > - > if (unlikely(current->flags & PF_KTHREAD)) > return; > > - if (current->throttle_queue != q) { > - if (!blk_get_queue(q)) > - return; > + if (current->throttle_disk != disk) { > + get_device(disk_to_dev(disk)); > > - if (current->throttle_queue) > - blk_put_queue(current->throttle_queue); > - current->throttle_queue = q; > + if (current->throttle_disk) > + put_disk(current->throttle_disk); > + current->throttle_disk = disk; > } > > if (use_memdelay) > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 853d08f7562bda..6f6ce9ca709798 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -1436,7 +1436,7 @@ struct task_struct { > #endif > > #ifdef CONFIG_BLK_CGROUP > - struct request_queue *throttle_queue; > + struct gendisk *throttle_disk; > #endif > > #ifdef CONFIG_UPROBES > diff --git a/kernel/fork.c b/kernel/fork.c > index 9f7fe354189785..d9c97704b7c9a4 100644 > --- a/kernel/fork.c > +++ b/kernel/fork.c > @@ -1044,7 +1044,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) > #endif > > #ifdef CONFIG_BLK_CGROUP > - tsk->throttle_queue = NULL; > + tsk->throttle_disk = NULL; > tsk->use_memdelay = 0; > #endif > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 908a529bca12c9..3e0a742fb7bbff 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -3642,7 +3642,7 @@ void __cgroup_throttle_swaprate(struct page *page, gfp_t gfp_mask) > * We've already scheduled a throttle, avoid taking the global swap > * lock. > */ > - if (current->throttle_queue) > + if (current->throttle_disk) > return; > > spin_lock(&swap_avail_lock); > -- > 2.39.0 > -- Regards, Andreas SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nürnberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Martje Boudien Moerman (HRB 36809, AG Nürnberg)