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From: Yang Shi <>
To: Christoph Hellwig <>
Subject: Re: [RFC PATCH] fs: introduce ST_HUGE flag and set it to tmpfs and hugetlbfs
Date: Thu, 19 Apr 2018 17:18:20 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On 4/19/18 1:28 AM, Christoph Hellwig wrote:
> On Wed, Apr 18, 2018 at 11:18:25AM -0700, Yang Shi wrote:
>> Yes, thanks for the suggestion. I did think about it before I went with the
>> new flag. Not like hugetlb, THP will *not* guarantee huge page is used all
>> the time, it may fallback to regular 4K page or may get split. I'm not sure
>> how the applications use f_bsize field, it might break existing applications
>> and the value might be abused by applications to have counter optimization.
>> So, IMHO, a new flag may sound safer.
> But st_blksize isn't the block size, that is why I suggested it.  It is
> the preferred I/O size, and various file systems can report way
> larger values than the block size already.

Thanks. If it is safe to applications, It definitely can return huge 
page size via st_blksize.

Is it safe to return huge page size via statfs->f_bsize? It sounds it 
has not to be the physical block size too. The man page says it is 
"Optimal transfer block size".


  parent reply	other threads:[~2018-04-20  0:18 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-17 21:08 Yang Shi
2018-04-17 21:31 ` Andrew Morton
2018-04-17 21:51   ` Yang Shi
2018-04-17 23:22 ` Matthew Wilcox
2018-04-17 23:37   ` Yang Shi
2018-04-18 10:27 ` Christoph Hellwig
2018-04-18 18:18   ` Yang Shi
2018-04-19  8:28     ` Christoph Hellwig
2018-04-19  9:05       ` Kirill A. Shutemov
2018-04-20  0:18       ` Yang Shi [this message]
2018-04-18 20:26 ` Mike Kravetz
2018-04-18 20:53   ` Yang Shi
2018-04-19  9:01   ` Kirill A. Shutemov

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