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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Gao Xiang <gaoxiang25@huawei.com>
Cc: devel@driverdev.osuosl.org, linux-erofs@lists.ozlabs.org,
	Chao Yu <yuchao0@huawei.com>, LKML <linux-kernel@vger.kernel.org>,
	weidu.du@huawei.com, Miao Xie <miaoxie@huawei.com>
Subject: Re: [PATCH 02/10] staging: erofs: fix race when the managed cache is enabled
Date: Thu, 22 Nov 2018 14:20:41 +0100	[thread overview]
Message-ID: <20181122132041.GA14300@kroah.com> (raw)
In-Reply-To: <fa61d737-216e-c644-5d23-28d520182262@huawei.com>

On Thu, Nov 22, 2018 at 08:41:15PM +0800, Gao Xiang wrote:
> Hi Greg,
> 
> On 2018/11/22 20:26, Greg Kroah-Hartman wrote:
> > Ugh, every page?  Ok, nevermind, I take back my objections.  You all are
> > crazy and need to do crazy things like this :)
> 
> ...Do you have some idea about this? ... I think it is fairly normal... :(
> 
> We have a large number of managed workgroups, the current use case is the 4k compressed size,
> each compressed page has a workgroup, but erofs also has reclaim paths to free them for low memory cases.
> 
> But since the structure (z_erofs_vle_workgroup, erofs_workgroup) is critical,
> I need to make it as small as possible.

I do not know "real" filesystems (i.e. ones that put stuff on disks),
only virtual ones (like sysfs/kernfs), so I do not know what to suggest
here, sorry.  I thought this was a much higner-level structure, if this
is per-compressed-page, then you are more than welcome to optimize for
this.  Good luck with your "fake" spinlocks though :)

thanks,

greg k-h

  reply	other threads:[~2018-11-22 13:20 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-20 14:34 [PATCH 00/10] staging: erofs: decompression stability enhancement Gao Xiang
2018-11-20 14:34 ` [PATCH 01/10] staging: erofs: fix `trace_erofs_readpage' position Gao Xiang
2018-11-22 10:19   ` Greg Kroah-Hartman
2018-11-22 10:49     ` Gao Xiang
2018-11-22 11:00       ` Greg Kroah-Hartman
2018-11-20 14:34 ` [PATCH 02/10] staging: erofs: fix race when the managed cache is enabled Gao Xiang
2018-11-22 10:17   ` Greg Kroah-Hartman
2018-11-22 10:42     ` Gao Xiang
2018-11-22 11:06       ` Greg Kroah-Hartman
2018-11-22 11:43         ` Gao Xiang
2018-11-22 12:26           ` Greg Kroah-Hartman
2018-11-22 12:41             ` Gao Xiang
2018-11-22 13:20               ` Greg Kroah-Hartman [this message]
2018-11-22 10:19   ` Greg Kroah-Hartman
2018-11-20 14:34 ` [PATCH 03/10] staging: erofs: atomic_cond_read_relaxed on ref-locked workgroup Gao Xiang
2018-11-22 10:20   ` Greg Kroah-Hartman
2018-11-20 14:34 ` [PATCH 04/10] staging: erofs: fix `erofs_workgroup_{try_to_freeze, unfreeze}' Gao Xiang
2018-11-22 10:21   ` Greg Kroah-Hartman
2018-11-22 10:29     ` Gao Xiang
2018-11-22 11:03       ` Greg Kroah-Hartman
2018-11-22 11:05       ` Greg Kroah-Hartman
2018-11-22 11:22         ` Gao Xiang
2018-11-20 14:34 ` [PATCH 05/10] staging: erofs: add a full barrier in erofs_workgroup_unfreeze Gao Xiang
2018-11-22 10:22   ` Greg Kroah-Hartman
2018-11-22 10:56     ` Gao Xiang
2018-11-22 18:50       ` Andrea Parri
2018-11-23  2:51         ` Gao Xiang
2018-11-23  9:51           ` Andrea Parri
2018-11-23 10:00             ` Gao Xiang
2018-11-20 14:34 ` [PATCH 06/10] staging: erofs: fix the definition of DBG_BUGON Gao Xiang
2018-11-20 14:34 ` [PATCH 07/10] staging: erofs: separate into init_once / always Gao Xiang
2018-11-22 10:23   ` Greg Kroah-Hartman
2018-11-22 10:34     ` Gao Xiang
2018-11-22 11:05       ` Greg Kroah-Hartman
2018-11-22 11:11         ` Gao Xiang
2018-11-22 11:26           ` Greg Kroah-Hartman
2018-11-22 11:37             ` Gao Xiang
2018-11-22 12:00             ` Gao Xiang
2018-11-22 13:01               ` Gao Xiang
2018-11-22 13:23                 ` Greg Kroah-Hartman
2018-11-22 13:59                   ` Gao Xiang
2018-11-20 14:34 ` [PATCH 08/10] staging: erofs: locked before registering for all new workgroups Gao Xiang
2018-11-22 10:24   ` Greg Kroah-Hartman
2018-11-22 10:35     ` Gao Xiang
2018-11-20 14:34 ` [PATCH 09/10] staging: erofs: decompress asynchronously if PG_readahead page at first Gao Xiang
2018-11-20 14:34 ` [PATCH 10/10] staging: erofs: rename strange variable names in z_erofs_vle_frontend Gao Xiang

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