Let's introduce multi-reference pclusters at runtime. In details,
if one pcluster is requested by multiple extents at almost the same
time (even belong to different files), the longest extent will be
decompressed as representative and the other extents are actually
copied from the longest one in one round.
After this patch, fully-referenced extents can be correctly handled
and the full decoding check needs to be bypassed for
partial-referenced extents.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-17-hsiangkao@linux.alibaba.com
Currently, `pcl->length' records the longest decompressed length
as long as the pcluster itself isn't reclaimed. However, such
number is unneeded for the general cases since it doesn't indicate
the exact decompressed size in this round.
Instead, let's record the decompressed size for this round instead,
thus `pcl->nr_pages' can be completely dropped and pageofs_out is
also designed to be kept in sync with `pcl->length'.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-16-hsiangkao@linux.alibaba.com
For the most cases, small pclusters can be decompressed with page
arrays on stack.
Try to leave both (de)compressed_pages on stack if possible as before.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-14-hsiangkao@linux.alibaba.com
Let's introduce struct z_erofs_decompress_backend in order to pass
on the decompression backend context between helper functions more
easier and avoid too many arguments.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-13-hsiangkao@linux.alibaba.com
In order to introduce multi-reference pclusters for compressed data
deduplication, let's get rid of the global page array for now since
it needs to be re-designed then at least.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-12-hsiangkao@linux.alibaba.com
`enum z_erofs_collectmode' is really ambiguous, but I'm not quite
sure if there are better naming, basically it's used to judge whether
inplace I/O can be used due to the current status of pclusters in
the chain.
Rename it as `enum z_erofs_pclustermode' instead.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-11-hsiangkao@linux.alibaba.com
Since all decompressed offsets have been integrated to bvecs[], this
patch avoids all sub-indexes so that page->private only includes a
part count and an eio flag, thus in the future folio->private can have
the same meaning.
In addition, PG_error will not be used anymore after this patch and
we're heading to use page->private (later folio->private) and
page->mapping (later folio->mapping) only.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-9-hsiangkao@linux.alibaba.com
Convert compressed_pages[] to bufvec in order to avoid using
page->private to keep onlinepage_index (decompressed offset)
for inplace I/O pages.
In the future, we only rely on folio->private to keep a countdown
to unlock folios and set folio_uptodate.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-8-hsiangkao@linux.alibaba.com
`z_erofs_decompress_pcluster()' is too long therefore it'd be better
to introduce another helper to parse compressed pages (or laterly,
compressed bvecs.)
BTW, since `compressed_bvecs' is too long as a part of the function
name, `in_bvecs' is used here instead.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-7-hsiangkao@linux.alibaba.com
Remove the old pagevec approach but keep z_erofs_page_type for now.
It will be reworked in the following commits as well.
Also rename Z_EROFS_NR_INLINE_PAGEVECS as Z_EROFS_INLINE_BVECS with
the new value 2 since it's actually enough to bootstrap.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-6-hsiangkao@linux.alibaba.com
For each pcluster, the total compressed buffers are determined in
advance, yet the number of decompressed buffers actually vary. Too
many decompressed pages can be recorded if one pcluster is highly
compressed or its pcluster size is large. That takes extra memory
footprints compared to uncompressed filesystems, especially a lot of
I/O in flight on low-ended devices.
Therefore, similar to inplace I/O, pagevec was introduced to reuse
page cache to store these pointers in the time-sharing way since
these pages are actually unused before decompressing.
In order to make it more flexable, a cleaner bufvec is used to
replace the old pagevec stuffs so that
- Decompressed offsets can be stored inline, thus it can be used
for the upcoming feature like compressed data deduplication.
It's calculated by `page_offset(page) - map->m_la';
- Towards supporting large folios for compressed inodes since
our final goal is to completely avoid page->private but use
folio->private only for all page cache pages.
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-5-hsiangkao@linux.alibaba.com
`z_erofs_decompress_pcluster()' is too long therefore it'd be better
to introduce another helper to parse decompressed pages (or laterly,
decompressed bvecs.)
BTW, since `decompressed_bvecs' is too long as a part of the function
name, `out_bvecs' is used instead.
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-4-hsiangkao@linux.alibaba.com
Since commit 5c6dcc57e2 ("erofs: get rid of
`struct z_erofs_collector'"), these arguments can be dropped as well.
No logic changes.
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220715154203.48093-2-hsiangkao@linux.alibaba.com
- Leave compressed inodes unsupported in fscache mode for now;
- Avoid crash when using tracepoint cachefiles_prep_read;
- Fix `backmost' behavior due to a recent cleanup;
- Update documentation for better description of recent new features;
- Several decompression cleanups w/o logical change.
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Merge tag 'erofs-for-5.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull more erofs updates from Gao Xiang:
"This is a follow-up to the main updates, including some fixes of
fscache mode related to compressed inodes and a cachefiles tracepoint.
There is also a patch to fix an unexpected decompression strategy
change due to a cleanup in the past. All the fixes are quite small.
Apart from these, documentation is also updated for a better
description of recent new features.
In addition, this has some trivial cleanups without actual code logic
changes, so I could have a more recent codebase to work on folios and
avoiding the PG_error page flag for the next cycle.
Summary:
- Leave compressed inodes unsupported in fscache mode for now
- Avoid crash when using tracepoint cachefiles_prep_read
- Fix `backmost' behavior due to a recent cleanup
- Update documentation for better description of recent new features
- Several decompression cleanups w/o logical change"
* tag 'erofs-for-5.19-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: fix 'backmost' member of z_erofs_decompress_frontend
erofs: simplify z_erofs_pcluster_readmore()
erofs: get rid of label `restart_now'
erofs: get rid of `struct z_erofs_collection'
erofs: update documentation
erofs: fix crash when enable tracepoint cachefiles_prep_read
erofs: leave compressed inodes unsupported in fscache mode for now
It was incompletely introduced for deduplication between different
logical extents backed with the same pcluster.
We will have a better in-memory representation in the next release
cycle for this, as well as partial memory folios support. So get rid
of it instead.
No logic changes.
Link: https://lore.kernel.org/r/20220529055425.226363-2-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
This is a "weak" conversion which converts straight back to using pages.
A full conversion should be performed at some point, hopefully by
someone familiar with the filesystem.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
- Avoid using page structure directly for all uncompressed paths;
- Fix a double-free issue when sysfs initialization fails;
- Complete DAX description for erofs;
- Use mtime instead since there's no (easy) way for users to control
ctime;
- Several code cleanups.
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Merge tag 'erofs-for-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs updates from Gao Xiang:
"In this cycle, we continue converting to use meta buffers for all
remaining uncompressed paths to prepare for the upcoming subpage,
folio and fscache features.
We also fixed a double-free issue when sysfs initialization fails,
which was reported by syzbot.
Besides, in order for the userspace to control per-file timestamp
easier, we now switch to record mtime instead of ctime with a
compatible feature marked. And there are also some code cleanups and
documentation update as usual.
Summary:
- Avoid using page structure directly for all uncompressed paths
- Fix a double-free issue when sysfs initialization fails
- Complete DAX description for erofs
- Use mtime instead since there's no (easy) way for users to control
ctime
- Several code cleanups"
* tag 'erofs-for-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: rename ctime to mtime
erofs: use meta buffers for inode lookup
erofs: use meta buffers for reading directories
fs: erofs: add sanity check for kobject in erofs_unregister_sysfs
erofs: refine managed inode stuffs
erofs: clean up z_erofs_extent_lookback
erofs: silence warnings related to impossible m_plen
Documentation/filesystem/dax: update DAX description on erofs
erofs: clean up preload_compressed_pages()
erofs: get rid of `struct z_erofs_collector'
erofs: use meta buffers for erofs_read_superblock()
Rename preload_compressed_pages() as z_erofs_bind_cache()
since we're trying to prepare for adapting folios.
Also, add a comment for the gfp setting. No logic changes.
Link: https://lore.kernel.org/r/20220301194951.106227-2-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Avoid `struct z_erofs_collector' since there is another context
structure called "struct z_erofs_decompress_frontend".
No logic changes.
Link: https://lore.kernel.org/r/20220301194951.106227-1-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@coolpad.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Pass the block_device and operation that we plan to use this bio for to
bio_alloc to optimize the assignment. NULL/0 can be passed, both for the
passthrough case on a raw request_queue and to temporarily avoid
refactoring some nasty code.
Also move the gfp_mask argument after the nr_vecs argument for a much
more logical calling convention matching what most of the kernel does.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-18-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Get rid of old erofs_get_meta_page() within zmap operations by
using on-stack meta buffers in order to prepare subpage and folio
features.
Finally, erofs_get_meta_page() is useless. Get rid of it!
Link: https://lore.kernel.org/r/20220102040017.51352-6-hsiangkao@linux.alibaba.com
Reviewed-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Currently, we have already support tail-packing inline for
uncompressed file, let's also implement this for compressed
files to save I/Os and storage space.
Different from normal pclusters, compressed data is available
in advance because of other metadata I/Os. Therefore, they
directly move into the bypass queue without extra I/O submission.
It's the last compression feature before folio/subpage support.
Link: https://lore.kernel.org/r/20211228232919.21413-1-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Although readpage is a synchronous path, there will be no additional
kworker scheduling overhead in non-atomic contexts together with
dm-verity.
Let's add a sysfs node to disable sync decompression as an option.
Link: https://lore.kernel.org/r/20211206143552.8384-1-huangjianan@oppo.com
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Huang Jianan <huangjianan@oppo.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
- fix unsafe pagevec reuse which could cause unexpected behaviors;
- get rid of the unused DELAYEDALLOC strategy.
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Merge tag 'erofs-for-5.16-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs
Pull erofs fixes from Gao Xiang:
- fix unsafe pagevec reuse which could cause unexpected behaviors
- get rid of the unused DELAYEDALLOC strategy that has been replaced by
TRYALLOC
* tag 'erofs-for-5.16-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
erofs: remove useless cache strategy of DELAYEDALLOC
erofs: fix unsafe pagevec reuse of hooked pclusters
After commit 1825c8d7ce ("erofs: force inplace I/O under low
memory scenario") and TRYALLOC is widely used, DELAYEDALLOC won't
be used anymore. Remove related dead code. Also, remove the blank
line at the end of zdata.h.
Link: https://lore.kernel.org/r/20211106082315.25781-1-huyue2@yulong.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <xiang@kernel.org>
There are pclusters in runtime marked with Z_EROFS_PCLUSTER_TAIL
before actual I/O submission. Thus, the decompression chain can be
extended if the following pcluster chain hooks such tail pcluster.
As the related comment mentioned, if some page is made of a hooked
pcluster and another followed pcluster, it can be reused for in-place
I/O (since I/O should be submitted anyway):
_______________________________________________________________
| tail (partial) page | head (partial) page |
|_____PRIMARY_HOOKED___|____________PRIMARY_FOLLOWED____________|
However, it's by no means safe to reuse as pagevec since if such
PRIMARY_HOOKED pclusters finally move into bypass chain without I/O
submission. It's somewhat hard to reproduce with LZ4 and I just found
it (general protection fault) by ro_fsstressing a LZMA image for long
time.
I'm going to actively clean up related code together with multi-page
folio adaption in the next few months. Let's address it directly for
easier backporting for now.
Call trace for reference:
z_erofs_decompress_pcluster+0x10a/0x8a0 [erofs]
z_erofs_decompress_queue.isra.36+0x3c/0x60 [erofs]
z_erofs_runqueue+0x5f3/0x840 [erofs]
z_erofs_readahead+0x1e8/0x320 [erofs]
read_pages+0x91/0x270
page_cache_ra_unbounded+0x18b/0x240
filemap_get_pages+0x10a/0x5f0
filemap_read+0xa9/0x330
new_sync_read+0x11b/0x1a0
vfs_read+0xf1/0x190
Link: https://lore.kernel.org/r/20211103182006.4040-1-xiang@kernel.org
Fixes: 3883a79abd ("staging: erofs: introduce VLE decompression support")
Cc: <stable@vger.kernel.org> # 4.19+
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Currently, ->lru is a way to arrange non-LRU pages and has some
in-kernel users. In order to minimize noticable issues of page
reclaim and cache thrashing under high memory presure, limited
temporary pages were all chained with ->lru and can be reused
during the request. However, it seems that ->lru could be removed
when folio is landing.
Let's use page->private to chain temporary pages for now instead
and transform EROFS formally after the topic of the folio / file
page design is finalized.
Link: https://lore.kernel.org/r/20211022090120.14675-1-hsiangkao@linux.alibaba.com
Cc: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Add MicroLZMA support in order to maximize compression ratios for
specific scenarios. For example, it's useful for low-end embedded
boards and as a secondary algorithm in a file for specific access
patterns.
MicroLZMA is a new container format for raw LZMA1, which was created
by Lasse Collin aiming to minimize old LZMA headers and get rid of
unnecessary EOPM (end of payload marker) as well as to enable
fixed-sized output compression, especially for 4KiB pclusters.
Similar to LZ4, inplace I/O approach is used to minimize runtime
memory footprint when dealing with I/O. Overlapped decompression is
handled with 1) bounced buffer for data under processing or 2) extra
short-lived pages from the on-stack pagepool which will be shared in
the same read request (128KiB for example).
Link: https://lore.kernel.org/r/20211010213145.17462-8-xiang@kernel.org
Acked-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Previously, the readahead window was strictly followed by EROFS
decompression strategy in order to minimize extra memory footprint.
However, it could become inefficient if just reading the partial
requested data for much big LZ4 pclusters and the upcoming LZMA
implementation.
Let's try to request the leading data in a pcluster without
triggering memory reclaiming instead for the LZ4 approach first
to boost up 100% randread of large big pclusters, and it has no real
impact on low memory scenarios.
It also introduces a way to expand read lengths in order to decompress
the whole pcluster, which is useful for LZMA since the algorithm
itself is relatively slow and causes CPU bound, but LZ4 is not.
Link: https://lore.kernel.org/r/20211008200839.24541-4-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Currently, z_erofs_map_blocks_iter() returns whether extents are
compressed or not, and the decompression frontend gets the specific
algorithms then.
It works but not quite well in many aspests, for example:
- The decompression frontend has to deal with whether extents are
compressed or not again and lookup the algorithms if compressed.
It's duplicated and too detailed about the on-disk mapping.
- A new secondary compression head will be introduced later so that
each file can have 2 compression algorithms at most for different
type of data. It could increase the complexity of the decompression
frontend if still handled in this way;
- A new readmore decompression strategy will be introduced to get
better performance for much bigger pcluster and lzma, which needs
the specific algorithm in advance as well.
Let's look up compression algorithms in z_erofs_map_blocks_iter()
directly instead.
Link: https://lore.kernel.org/r/20211008200839.24541-2-xiang@kernel.org
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
In order to support multi-layer container images, add multiple
device feature to EROFS. Two ways are available to use for now:
- Devices can be mapped into 32-bit global block address space;
- Device ID can be specified with the chunk indexes format.
Note that it assumes no extent would cross device boundary and mkfs
should take care of it seriously.
In the future, a dedicated device manager could be introduced then
thus extra devices can be automatically scanned by UUID as well.
Link: https://lore.kernel.org/r/20211014081010.43485-1-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Previously, EROFS mount options are all in the basic types, so
erofs_fs_context can be directly copied with assignment. However,
when the multiple device feature is introduced, it's hard to handle
multiple device information like the other basic mount options.
Let's separate basic mount option usage from fs_context, thus
multiple device information can be handled gracefully then.
No logic changes.
Link: https://lore.kernel.org/r/20211007070224.12833-1-hsiangkao@linux.alibaba.com
Reviewed-by: Chao Yu <chao@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
The mapping is not used at all, remove it and update related code.
Link: https://lore.kernel.org/r/20210810072416.1392-1-zbestahu@gmail.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
We already have the wrapper function to identify managed page.
Link: https://lore.kernel.org/r/20210810065450.1320-1-zbestahu@gmail.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yue Hu <huyue2@yulong.com>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
No any behavior to variable occupied in z_erofs_attach_page() which
is only caller to z_erofs_pagevec_enqueue().
Link: https://lore.kernel.org/r/20210419102623.2015-1-zbestahu@gmail.com
Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Gao Xiang <xiang@kernel.org>
Signed-off-by: Gao Xiang <xiang@kernel.org>
When picking up inplace I/O pages, it should be traversed in reverse
order in aligned with the traversal order of file-backed online pages.
Also, index should be updated together when preloading compressed pages.
Previously, only page-sized pclustersize was supported so no problem
at all. Also rename `compressedpages' to `icpage_ptr' to reflect its
functionality.
Link: https://lore.kernel.org/r/20210407043927.10623-5-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Since multiple pcluster sizes could be used at once, the number of
compressed pages will become a variable factor. It's necessary to
introduce slab pools rather than a single slab cache now.
This limits the pclustersize to 1M (Z_EROFS_PCLUSTER_MAX_SIZE), and
get rid of the obsolete EROFS_FS_CLUSTER_PAGE_LIMIT, which has no
use now.
Link: https://lore.kernel.org/r/20210407043927.10623-4-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
Formal big pcluster design is actually more powerful / flexable than
the previous thought whose pclustersize was fixed as power-of-2 blocks,
which was obviously inefficient and space-wasting. Instead, pclustersize
can now be set independently for each pcluster, so various pcluster
sizes can also be used together in one file if mkfs wants (for example,
according to data type and/or compression ratio).
Let's get rid of previous physical_clusterbits[] setting (also notice
that corresponding on-disk fields are still 0 for now). Therefore,
head1/2 can be used for at most 2 different algorithms in one file and
again pclustersize is now independent of these.
Link: https://lore.kernel.org/r/20210407043927.10623-2-xiang@kernel.org
Acked-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <hsiangkao@redhat.com>
