Message-ID: <20240805132459.ndyofuoyyojqctgt@quentin>
Date: Mon, 5 Aug 2024 13:24:59 +0000
From: "Pankaj Raghav (Samsung)" <kernel@...kajraghav.com>
To: willy@...radead.org
Cc: yang@...amperecomputing.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, john.g.garry@...cle.com,
	linux-fsdevel@...r.kernel.org, hare@...e.de, p.raghav@...sung.com,
	mcgrof@...nel.org, gost.dev@...sung.com, cl@...amperecomputing.com,
	linux-xfs@...r.kernel.org, ryan.roberts@....com, hch@....de,
	Zi Yan <ziy@...dia.com>, david@...morbit.com,
	chandan.babu@...cle.com, djwong@...nel.org, brauner@...nel.org,
	akpm@...ux-foundation.org
Subject: Re: [PATCH v11 00/10] enable bs > ps in XFS

@willy

The following patches that relevant to you but are missing your RVB. 
Do you think you can take a look when you have time?

readahead: allocate folios with mapping_min_order in readahead
mm: split a folio in minimum folio order chunks

--
Pankaj

> From: Pankaj Raghav <p.raghav@...sung.com>
> 
> This is the 11th version of the series that enables block size > page size
> (Large Block Size) in XFS.
> The context and motivation can be seen in cover letter of the RFC v1 [0].
> We also recorded a talk about this effort at LPC [1], if someone would
> like more context on this effort.
> 
> A lot of emphasis has been put on testing using kdevops, starting with an XFS
> baseline [3]. The testing has been split into regression and progression.
> 
> Regression testing:
> In regression testing, we ran the whole test suite to check for regressions on
> existing profiles due to the page cache changes.
> 
> I also ran split_huge_page_test selftest on XFS filesystem to check for
> huge page splits in min order chunks is done correctly.
> 
> No regressions were found with these patches added on top.
> 
> Progression testing:
> For progression testing, we tested for 8k, 16k, 32k and 64k block sizes.  To
> compare it with existing support, an ARM VM with 64k base page system (without
> our patches) was used as a reference to check for actual failures due to LBS
> support in a 4k base page size system.
> 
> There are some tests that assumes block size < page size that needs to be fixed.
> We have a tree with fixes for xfstests [4], most of the changes have been posted
> already, and only a few minor changes need to be posted. Already part of these
> changes has been upstreamed to fstests, and new tests have also been written and
> are out for review, namely for mmap zeroing-around corner cases, compaction
> and fsstress races on mm, and stress testing folio truncation on file mapped
> folios.
> 
> No new failures were found with the LBS support.
> 
> We've done some preliminary performance tests with fio on XFS on 4k block size
> against pmem and NVMe with buffered IO and Direct IO on vanilla Vs + these
> patches applied, and detected no regressions.
> 
> We also wrote an eBPF tool called blkalgn [5] to see if IO sent to the device
> is aligned and at least filesystem block size in length.
> 
> For those who want this in a git tree we have this up on a kdevops
> large-block-minorder-for-next-v11 tag [6].
> 
> [0] https://lore.kernel.org/lkml/20230915183848.1018717-1-kernel@pankajraghav.com/
> [1] https://www.youtube.com/watch?v=ar72r5Xf7x4
> [2] https://lkml.kernel.org/r/20240501153120.4094530-1-willy@infradead.org
> [3] https://github.com/linux-kdevops/kdevops/blob/master/docs/xfs-bugs.md
> 489 non-critical issues and 55 critical issues. We've determined and reported
> that the 55 critical issues have all fall into 5 common  XFS asserts or hung
> tasks  and 2 memory management asserts.
> [4] https://github.com/linux-kdevops/fstests/tree/lbs-fixes
> [5] https://github.com/iovisor/bcc/pull/4813
> [6] https://github.com/linux-kdevops/linux/
> [7] https://lore.kernel.org/linux-kernel/Zl20pc-YlIWCSy6Z@casper.infradead.org/#t
> 
> Changes since v10:
> - Revert back to silent clamping in mapping_set_folio_range().
> - Moved mapping_max_folio_size_supported() to patch 10.
> - Collected RVB from Darrick.
> 
> Dave Chinner (1):
>   xfs: use kvmalloc for xattr buffers
> 
> Luis Chamberlain (1):
>   mm: split a folio in minimum folio order chunks
> 
> Matthew Wilcox (Oracle) (1):
>   fs: Allow fine-grained control of folio sizes
> 
> Pankaj Raghav (7):
>   filemap: allocate mapping_min_order folios in the page cache
>   readahead: allocate folios with mapping_min_order in readahead
>   filemap: cap PTE range to be created to allowed zero fill in
>     folio_map_range()
>   iomap: fix iomap_dio_zero() for fs bs > system page size
>   xfs: expose block size in stat
>   xfs: make the calculation generic in xfs_sb_validate_fsb_count()
>   xfs: enable block size larger than page size support
> 
>  fs/iomap/buffered-io.c        |   4 +-
>  fs/iomap/direct-io.c          |  45 +++++++++++--
>  fs/xfs/libxfs/xfs_attr_leaf.c |  15 ++---
>  fs/xfs/libxfs/xfs_ialloc.c    |   5 ++
>  fs/xfs/libxfs/xfs_shared.h    |   3 +
>  fs/xfs/xfs_icache.c           |   6 +-
>  fs/xfs/xfs_iops.c             |   2 +-
>  fs/xfs/xfs_mount.c            |   8 ++-
>  fs/xfs/xfs_super.c            |  28 +++++---
>  include/linux/huge_mm.h       |  14 ++--
>  include/linux/pagemap.h       | 122 ++++++++++++++++++++++++++++++----
>  mm/filemap.c                  |  36 ++++++----
>  mm/huge_memory.c              |  59 ++++++++++++++--
>  mm/readahead.c                |  83 +++++++++++++++++------
>  14 files changed, 345 insertions(+), 85 deletions(-)
> 
> 
> base-commit: 2347b4c79f5e6cd3f4996e80c2d3c15f53006bf5
> -- 
> 2.44.1
> 

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