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 5A2B3C04FDF for ; Thu, 27 Jul 2023 08:48:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232064AbjG0Is1 (ORCPT ); Thu, 27 Jul 2023 04:48:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232598AbjG0IrW (ORCPT ); Thu, 27 Jul 2023 04:47:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3A92E59D1; Thu, 27 Jul 2023 01:30:13 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6A03F61DA8; Thu, 27 Jul 2023 08:30:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06711C433C7; Thu, 27 Jul 2023 08:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1690446606; bh=lgMwb11ItIJ27YCsuj2akQ0e0AMgpISaoiuOUrGiITY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Tr4M7HQ3pxhso0Q/eg4xKtwD0lUURtq4zUL2WnDxbX7YJArr/oNtVx0HKmYWbVJCj uZ3CjjOq76HigUmfxsBIfU5BJp2UCC8gXysiCMyY4oUiNa0NyuYtXgOb+GgYI2e2UD q/DMid3QMY2nJGias56vfjnyYrQ2kAGyvOg7az/lKKcQPYsllW1cAnQl1FfA/ktsaA ypQoOxGNqaMUpP2GFbXa8+1QKt5gSsrAShH7O9rxadTFuFxweU5IvbZDayprJj2afQ IGlbjA9TtQP0FcoHyTXu4yjcQ81VS0g2mOFp+HrXHsn6/kAwTiNlXyj4HVftm6tXbg kxbv5Cd7EwHzQ== Message-ID: Date: Thu, 27 Jul 2023 17:30:01 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3 28/49] dm zoned: dynamically allocate the dm-zoned-meta shrinker Content-Language: en-US To: Qi Zheng , akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru, vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org, brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu, steven.price@arm.com, cel@kernel.org, senozhatsky@chromium.org, yujie.liu@intel.com, gregkh@linuxfoundation.org, muchun.song@linux.dev Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-erofs@lists.ozlabs.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-mtd@lists.infradead.org, rcu@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Muchun Song References: <20230727080502.77895-1-zhengqi.arch@bytedance.com> <20230727080502.77895-29-zhengqi.arch@bytedance.com> From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <20230727080502.77895-29-zhengqi.arch@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 7/27/23 17:04, Qi Zheng wrote: > In preparation for implementing lockless slab shrink, use new APIs to > dynamically allocate the dm-zoned-meta shrinker, so that it can be freed > asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU > read-side critical section when releasing the struct dmz_metadata. > > Signed-off-by: Qi Zheng > Reviewed-by: Muchun Song > --- > drivers/md/dm-zoned-metadata.c | 28 ++++++++++++++++------------ > 1 file changed, 16 insertions(+), 12 deletions(-) > > diff --git a/drivers/md/dm-zoned-metadata.c b/drivers/md/dm-zoned-metadata.c > index 9d3cca8e3dc9..0bcb26a43578 100644 > --- a/drivers/md/dm-zoned-metadata.c > +++ b/drivers/md/dm-zoned-metadata.c > @@ -187,7 +187,7 @@ struct dmz_metadata { > struct rb_root mblk_rbtree; > struct list_head mblk_lru_list; > struct list_head mblk_dirty_list; > - struct shrinker mblk_shrinker; > + struct shrinker *mblk_shrinker; > > /* Zone allocation management */ > struct mutex map_lock; > @@ -615,7 +615,7 @@ static unsigned long dmz_shrink_mblock_cache(struct dmz_metadata *zmd, > static unsigned long dmz_mblock_shrinker_count(struct shrinker *shrink, > struct shrink_control *sc) > { > - struct dmz_metadata *zmd = container_of(shrink, struct dmz_metadata, mblk_shrinker); > + struct dmz_metadata *zmd = shrink->private_data; > > return atomic_read(&zmd->nr_mblks); > } > @@ -626,7 +626,7 @@ static unsigned long dmz_mblock_shrinker_count(struct shrinker *shrink, > static unsigned long dmz_mblock_shrinker_scan(struct shrinker *shrink, > struct shrink_control *sc) > { > - struct dmz_metadata *zmd = container_of(shrink, struct dmz_metadata, mblk_shrinker); > + struct dmz_metadata *zmd = shrink->private_data; > unsigned long count; > > spin_lock(&zmd->mblk_lock); > @@ -2936,19 +2936,23 @@ int dmz_ctr_metadata(struct dmz_dev *dev, int num_dev, > */ > zmd->min_nr_mblks = 2 + zmd->nr_map_blocks + zmd->zone_nr_bitmap_blocks * 16; > zmd->max_nr_mblks = zmd->min_nr_mblks + 512; > - zmd->mblk_shrinker.count_objects = dmz_mblock_shrinker_count; > - zmd->mblk_shrinker.scan_objects = dmz_mblock_shrinker_scan; > - zmd->mblk_shrinker.seeks = DEFAULT_SEEKS; > > /* Metadata cache shrinker */ > - ret = register_shrinker(&zmd->mblk_shrinker, "dm-zoned-meta:(%u:%u)", > - MAJOR(dev->bdev->bd_dev), > - MINOR(dev->bdev->bd_dev)); > - if (ret) { > - dmz_zmd_err(zmd, "Register metadata cache shrinker failed"); > + zmd->mblk_shrinker = shrinker_alloc(0, "dm-zoned-meta:(%u:%u)", > + MAJOR(dev->bdev->bd_dev), > + MINOR(dev->bdev->bd_dev)); > + if (!zmd->mblk_shrinker) { > + dmz_zmd_err(zmd, "Allocate metadata cache shrinker failed"); ret is not set here, so dmz_ctr_metadata() will return success. You need to add: ret = -ENOMEM; or something. > goto err; > } > > + zmd->mblk_shrinker->count_objects = dmz_mblock_shrinker_count; > + zmd->mblk_shrinker->scan_objects = dmz_mblock_shrinker_scan; > + zmd->mblk_shrinker->seeks = DEFAULT_SEEKS; > + zmd->mblk_shrinker->private_data = zmd; > + > + shrinker_register(zmd->mblk_shrinker); I fail to see how this new shrinker API is better... Why isn't there a shrinker_alloc_and_register() function ? That would avoid adding all this code all over the place as the new API call would be very similar to the current shrinker_register() call with static allocation. > + > dmz_zmd_info(zmd, "DM-Zoned metadata version %d", zmd->sb_version); > for (i = 0; i < zmd->nr_devs; i++) > dmz_print_dev(zmd, i); > @@ -2995,7 +2999,7 @@ int dmz_ctr_metadata(struct dmz_dev *dev, int num_dev, > */ > void dmz_dtr_metadata(struct dmz_metadata *zmd) > { > - unregister_shrinker(&zmd->mblk_shrinker); > + shrinker_free(zmd->mblk_shrinker); > dmz_cleanup_metadata(zmd); > kfree(zmd); > } -- Damien Le Moal Western Digital Research