Received-SPF: pass (google.com: domain of linux-kernel+bounces-33009-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
From: Naohiro Aota <Naohiro.Aota@wdc.com>
To: Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
CC: Josef Bacik <josef@toxicpanda.com>, David Sterba <dsterba@suse.com>,
	"linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Damien Le Moal
	<dlemoal@kernel.org>
Subject: Re: [PATCH 2/2] btrfs: zoned: wake up cleaner sooner if needed
Thread-Topic: [PATCH 2/2] btrfs: zoned: wake up cleaner sooner if needed
Thread-Index: AQHaTSDvOd+kWBN8wkSOr2ka96SkX7DlwQgA
Date: Mon, 22 Jan 2024 12:22:20 +0000
Message-ID: <x6bi4u2u65q37tde3s357lzhce4wglpobfgp7qgzhun4iadg3m@2pewiu6xuts4>
References: <20240122-reclaim-fix-v1-0-761234a6d005@wdc.com>
 <20240122-reclaim-fix-v1-2-761234a6d005@wdc.com>
In-Reply-To: <20240122-reclaim-fix-v1-2-761234a6d005@wdc.com>
Accept-Language: ja-JP, en-US
Content-Language: en-US
wdcipoutbound: EOP-TRUE
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0:
 =?us-ascii?Q?KxHE0a3NSV29MHt2LZXFQHMTIbWmFEv8jRtvwCcGjMBpz6lQoaW/Bxt/cFxb?=
 =?us-ascii?Q?1XNO+xkRmBDJruB3sRnHynRo0Lcj3T7ooaLVCqXDMi1zoCfhs2WwwY7yjKtn?=
 =?us-ascii?Q?EIhRQusZSpqDMkvvVPhxpTYlxmwwXxYyTQA6Foopso4fy+6frRMsESlLJgFw?=
 =?us-ascii?Q?BiiYohrTk3o/rStsvFiyzVRoB6tJ1QyX/jW1DuMe3jnnGMec8ZiXqoDvWGmI?=
 =?us-ascii?Q?+oslqpzuupl6HglvRyXN4jzyC36aJKt0D2T1L5YahRC54AJnKE4+2OuBdTDA?=
 =?us-ascii?Q?PS4yvhmtRCfs7me6TmrBiPLhYjvHpolkSB5LnoJ6bJHDmJV7fEHhNPIHyVDB?=
 =?us-ascii?Q?PIp7M9rsNGWiUQbmI2qh1TdNEiZDUtAKI0YttkvzE4s2AmU9wisykxBgh23S?=
 =?us-ascii?Q?I3ZwPYtsFXyJBP2PJuqgebbTV0z4GhdSerfmNwlQ218K+FWY3V+KyXNvEWtz?=
 =?us-ascii?Q?okb1nx/kv0a/D8Zjsvf6KSPI0Lui4aP8FCW/yApHvUHUR5udNgauYELH3v2t?=
 =?us-ascii?Q?Xqlv3t4Fiabp4G5AUBkelaJ6iHT6FGvedOkhbmWfpFo+vzpDXCS6F/08NFPs?=
 =?us-ascii?Q?OuoGMCmYg+rq9WRRIycFgRbdnyRCeEVjRSLjVvc67uRKUWBGDfsPRNStiZCK?=
 =?us-ascii?Q?5S+pNcACQR2J627JGGWFyof+elTNW0k6X25An9ucEWzJ6ojeoXdNFUh0XIWh?=
 =?us-ascii?Q?H6aWv+jvyBQXOzc7yXLBxCMqVhyAeurberXb6n7Zd2257vMK7/vASmzxEFY7?=
 =?us-ascii?Q?8keql0abnM6RzLvuP9uNeeVSIjyvRk+pcIwwOfg+lgnI6i6jHMvgh5LPiUzN?=
 =?us-ascii?Q?dir5B18hvXZNMVeCisS/ryLP5ecpbzjjTzG9MSYiF2wxKziK3DA/qTGuC+ep?=
 =?us-ascii?Q?wuJjNjRzIXp7wJ3v24JSVbxbLfXJp0XLRS8E+u9hbH7MFqCDLxWmUORFtaoG?=
 =?us-ascii?Q?QXKg3c0RoAtmoN+DhRXazpufGzEczhCB6PEj188VvHBfW/FRgZJaP+E4MjYY?=
 =?us-ascii?Q?cJoPMyabcHwxnF6PomGjXKobEHrxZBUesHOZft4/PHNkPgOWGXzRHCC677FL?=
 =?us-ascii?Q?6DAl4RJgpl2aJtj5OWzlnRUXt8ba7nv/Wj4nRF0A/f1R6654pvRxCLieLovv?=
 =?us-ascii?Q?4dUavoGoIww63dNzesLC9GeAyQZ71L5ekzW/cKnJpRnLUkX+HN313lVdHZLV?=
 =?us-ascii?Q?TRMAkg1EbJmlA+kdmfFQWE3uHeOyHCz69ITzeJOj31Q311sdzne2QJwvjvXw?=
 =?us-ascii?Q?4UyHZ4os/35xSXLIvHtv0VafzzrCv40eTojNnwcU9WNWmKe3lXugX3c55EoT?=
 =?us-ascii?Q?9PcB4pbQJlQetjXzK/3IXob9lY0VWKghIzmn7ipH0K0VPueXXetAJ1TYHFWK?=
 =?us-ascii?Q?PjQqtO/0/hOJk5yomNINEB6VEB5AeIaq5oRRNvwsve30qoQ0eYFnEgysYF6Q?=
 =?us-ascii?Q?x01x3e2+2SZ5EfPGTxvT2v7mv641UsO6qcc5scPvh+99O3vt4kJbba6mDiSs?=
 =?us-ascii?Q?cFWufF7E9FR90uWDDgZWWk9BCmoYkUKlOVabmb2DIVahvwBwzb4f+F9+wTnd?=
 =?us-ascii?Q?LKb4KncpOAzqqP/j2G9ZisnXmv53xRvW7BRbbbZ4RInrg8YPv1TlSa1kN2sA?=
 =?us-ascii?Q?ig=3D=3D?=
Content-Type: text/plain; charset="us-ascii"
Content-ID: <5D0E8357D88FAA42B0F5E56EEA5C6F27@namprd04.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
Precedence: bulk
X-Mailing-List: linux-kernel@vger.kernel.org
List-Id: <linux-kernel.vger.kernel.org>
List-Subscribe: <mailto:linux-kernel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:linux-kernel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0:
	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
X-OriginatorOrg: wdc.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SJ0PR04MB7776.namprd04.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 0da9fa64-57d7-4ac2-6a00-08dc1b44c806
X-MS-Exchange-CrossTenant-originalarrivaltime: 22 Jan 2024 12:22:20.6781
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: b61c8803-16f3-4c35-9b17-6f65f441df86
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: Mfyufsv2u4wIjmzDpsq4YMauy/n8JlNX6FMniKiTuMxU0/0ygpZ5lg4TBaUfji0Bcz4q8TTGIBBE8b7K/gY7Bg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA3PR04MB8929

On Mon, Jan 22, 2024 at 02:51:04AM -0800, Johannes Thumshirn wrote:
> On very fast but small devices, waiting for a transaction commit can be
> too long of a wait in order to wake up the cleaner kthread to remove unus=
ed
> and reclaimable block-groups.
>=20
> Check every time we're adding back free space to a block group, if we nee=
d
> to activate the cleaner kthread.
>=20
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> ---
>  fs/btrfs/free-space-cache.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>=20
> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
> index d372c7ce0e6b..2d98b9ca0e83 100644
> --- a/fs/btrfs/free-space-cache.c
> +++ b/fs/btrfs/free-space-cache.c
> @@ -30,6 +30,7 @@
>  #include "file-item.h"
>  #include "file.h"
>  #include "super.h"
> +#include "zoned.h"
> =20
>  #define BITS_PER_BITMAP		(PAGE_SIZE * 8UL)
>  #define MAX_CACHE_BYTES_PER_GIG	SZ_64K
> @@ -2694,6 +2695,7 @@ int __btrfs_add_free_space(struct btrfs_block_group=
 *block_group,
>  static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_=
group,
>  					u64 bytenr, u64 size, bool used)
>  {
> +	struct btrfs_fs_info *fs_info =3D block_group->fs_info;
>  	struct btrfs_space_info *sinfo =3D block_group->space_info;
>  	struct btrfs_free_space_ctl *ctl =3D block_group->free_space_ctl;
>  	u64 offset =3D bytenr - block_group->start;
> @@ -2745,6 +2747,10 @@ static int __btrfs_add_free_space_zoned(struct btr=
fs_block_group *block_group,
>  		btrfs_mark_bg_to_reclaim(block_group);
>  	}
> =20
> +	if (btrfs_zoned_should_reclaim(fs_info) &&
> +	    !test_bit(BTRFS_FS_CLEANER_RUNNING, &fs_info->flags))
> +		wake_up_process(fs_info->cleaner_kthread);
> +

Isn't it too costly to call btrfs_zoned_should_reclaim() every time
something updated? Can we wake up it in btrfs_mark_bg_to_reclaim and
btrfs_mark_bg_unused ?

Also, looking into btrfs_zoned_should_reclaim(), it sums device->bytes_used
for each fs_devices->devices. And, device->bytes_used is set at
create_chunk() or at btrfs_remove_chunk(). Isn't it feasible to do the
calculation only there?

>  	return 0;
>  }
> =20
>=20
> --=20
> 2.43.0
> =