From: Chao Yu <chao@kernel.org>
To: Gao Xiang <hsiangkao@aol.com>, Chao Yu <yuchao0@huawei.com>,
devel@driverdev.osuosl.org
Cc: Gao Xiang <gaoxiang25@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-erofs@lists.ozlabs.org, Miao Xie <miaoxie@huawei.com>,
LKML <linux-kernel@vger.kernel.org>, Du Wei <weidu.du@huawei.com>
Subject: Re: [PATCH 4/6] staging: erofs: cleanup `z_erofs_vle_normalaccess_readpages'
Date: Wed, 19 Sep 2018 23:45:43 +0800 [thread overview]
Message-ID: <37b566ea-273b-8d81-7428-06bd35d60092@kernel.org> (raw)
In-Reply-To: <fc0f977f-b1c3-41a9-a058-bca4261bf9ea@aol.com>
Hi Xiang,
On 2018/9/19 23:32, Gao Xiang wrote:
> Hi Chao,
>
> On 2018/9/19 23:26, Chao Yu wrote:
>> Hi Xiang,
>>
>> On 2018/9/19 13:49, Gao Xiang wrote:
>>> This patch introduces `__should_decompress_synchronously' to
>>> cleanup `z_erofs_vle_normalaccess_readpages'.
>>>
>>> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
>>> ---
>>> drivers/staging/erofs/internal.h | 11 +++++++++++
>>> drivers/staging/erofs/super.c | 5 +++++
>>> drivers/staging/erofs/unzip_vle.c | 20 ++++++--------------
>>> 3 files changed, 22 insertions(+), 14 deletions(-)
>>>
>>> diff --git a/drivers/staging/erofs/internal.h b/drivers/staging/erofs/internal.h
>>> index cfcc6db..c84eb97 100644
>>> --- a/drivers/staging/erofs/internal.h
>>> +++ b/drivers/staging/erofs/internal.h
>>> @@ -95,6 +95,9 @@ struct erofs_sb_info {
>>> /* the dedicated workstation for compression */
>>> struct radix_tree_root workstn_tree;
>>>
>>> + /* threshold for decompression synchronously */
>>> + unsigned int max_sync_decompress_pages;
>>> +
>>> #ifdef EROFS_FS_HAS_MANAGED_CACHE
>>> struct inode *managed_cache;
>>> #endif
>>> @@ -273,6 +276,14 @@ extern int erofs_try_to_free_cached_page(struct address_space *mapping,
>>> struct page *page);
>>> #endif
>>>
>>> +#define DEFAULT_MAX_SYNC_DECOMPRESS_PAGES 4
>>> +
>>> +static inline bool __should_decompress_synchronously(struct erofs_sb_info *sbi,
>>> + unsigned int nr)
>>> +{
>>> + return nr <= sbi->max_sync_decompress_pages;
>> - nr_pages < 4 /* sync */);
>>
>> There is a little bit changed except cleanup, IIUC, would it be any difference
>> of performance around boundary of four pages?
>
> No.. Once synchronous decompression is applied for 1,2,3 pages for no special reasons.
> But I think it could be better to adjust it to the power of two --- 1,2,3,4 is preferred.
> Since I have no idea to measure which is better or what value is best for all platform or use cases...
>
> Therefore I tune it in this patch since I don't like the number
> DEFAULT_MAX_SYNC_DECOMPRESS_PAGES == 3 ...
Yeah, how about adding one more patch to tune this magic number first? as that
change would not be part of cleanup thing. I guess later maybe we could export a
sysfs node to provider tuning ability on that threshold.
Thanks,
>
> Thanks,
> Gao Xiang
>
>>
>> Thanks,
>>
next prev parent reply other threads:[~2018-09-19 15:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-19 5:49 [PATCH 1/6] staging: erofs: remove redundant CONFIG_EROFS_FS_XATTRs Gao Xiang
2018-09-19 5:49 ` [PATCH 2/6] staging: erofs: fold in `__update_workgrp_llen' Gao Xiang
2018-09-19 15:14 ` Chao Yu
2018-09-19 5:49 ` [PATCH 3/6] staging: erofs: drop multiref support temporarily Gao Xiang
2018-09-19 15:20 ` Chao Yu
2018-09-19 5:49 ` [PATCH 4/6] staging: erofs: cleanup `z_erofs_vle_normalaccess_readpages' Gao Xiang
2018-09-19 15:26 ` Chao Yu
2018-09-19 15:32 ` Gao Xiang
2018-09-19 15:40 ` Gao Xiang
2018-09-19 15:45 ` Chao Yu [this message]
2018-09-19 15:51 ` Gao Xiang
2018-09-19 16:06 ` [PATCH v2 " Gao Xiang
2018-09-20 1:29 ` Chao Yu
2018-09-19 5:49 ` [PATCH 5/6] staging: erofs: add some comments for xattr subsystem Gao Xiang
2018-09-19 15:27 ` Chao Yu
2018-09-19 5:49 ` [PATCH 6/6] staging: erofs: simplify return value of `xattr_foreach' Gao Xiang
2018-09-19 15:28 ` Chao Yu
2018-09-19 15:07 ` [PATCH 1/6] staging: erofs: remove redundant CONFIG_EROFS_FS_XATTRs Chao Yu
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