Re: [PATCH v12 01/10] vfs, iomap: Fix generic_file_splice_read() to avoid reversion of ITER_PIPE

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, Feb 08, 2023 at 04:09:51PM +0000, David Howells wrote:
> How about one of two different solutions?
> 
>  (1) Repurpose the function I proposed for generic_file_splice_read() but only
>      for splicing from O_DIRECT files; reading from non-O_DIRECT files would
>      use an ITER_PIPE as upstream.

Given the amounts of problems we had with O_DIRECT vs splice, and the
fact that even doing this is a bit pointless that seems sensible to me.

>      for splicing from O_DIRECT files, as (1), but also replace the splice
>      from a buffered file with something like the patch below.  This uses
>      filemap_get_pages() to do the reading and to get a bunch of folios from
>      the pagecache that we can then splice into the pipe directly.

I defintively like the idea of killing ITER_PIPE.  Isn't the 16
folios in a folio tree often much less than what we could fit into
a single pipe buf?  Unless you have a file system that can use
huge folios for buffered I/O and actually does this might significantly
limit performance.

With that in mind I'll try to find some time to review your actual
patch, but I'm a little busy at the moment.



[Index of Archives]     [Linux RAID]     [Linux SCSI]     [Linux ATA RAID]     [IDE]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Device Mapper]

  Powered by Linux