Messages in this thread | | | Subject | Re: [RFC PATCH] fs: introduce ST_HUGE flag and set it to tmpfs and hugetlbfs | From | Yang Shi <> | Date | Thu, 19 Apr 2018 17:18:20 -0700 |
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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".
Yang
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