On Tue, Mar 1, 2022 at 8:10 PM Nick Terrell <terrelln@xxxxxx> wrote: > > > > > On Feb 20, 2022, at 1:45 AM, Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote: > > > > On Tue, Nov 9, 2021 at 2:24 AM Nick Terrell <nickrterrell@xxxxxxxxx> wrote: > >> > >> From: Nick Terrell <terrelln@xxxxxx> > >> > >> Hi Linus, > >> > >> I am sending you a pull request to add myself as the maintainer of zstd and > >> update the zstd version in the kernel, which is now 4 years out of date, > >> to the latest zstd release. This includes bug fixes, much more extensive fuzzing, > >> and performance improvements. And generates the kernel zstd automatically > >> from upstream zstd, so it is easier to keep the zstd verison up to date, and we > >> don't fall so far out of date again. > >> > >> Thanks, > >> Nick Terrell > >> > >> The following changes since commit d2f38a3c6507b2520101f9a3807ed98f1bdc545a: > >> > >> Merge tag 'backlight-next-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight (2021-11-08 12:21:28 -0800) > >> > >> are available in the Git repository at: > >> > >> git@xxxxxxxxxx:terrelln/linux.git tags/zstd-for-linus-v5.16 > >> > >> for you to fetch changes up to 0a8ea235837cc39f27c45689930aa97ae91d5953: > >> > >> lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical (2021-11-08 16:55:38 -0800) > >> > >> ---------------------------------------------------------------- > >> Update to zstd-1.4.10 > >> > > > > Hi Nick, > > > > where is the official ZSTD version 1.4.10 (see below links)? > > Can you clarify on this, please? > > The upstream tag v1.4.10 [0] is what is imported into the kernel. > > > v1.4.19 seems to be faster than v1.4.18 in some benchmarks. > > The background of question is I wanted to request a new zstd version > > for Debian (currently v1.4.18). > > There is no v1.4.18 or v1.4.19, I believe you meant v1.4.8 and v1.4.9. > Hehe, yes. Mixed that up with kernel release versions, maybe. > The latest zstd versions is v1.5.2. We do expect speed improvements > in v1.5.2. However, we don't manage the zstd package in any package > manager, Debian included. So we don't have control over the version > of zstd in Debian. > Just read about the speed improvements (even post v1.4.8). I wanted to request a version bump to 1.4.10 via Debian's reportbug tool. There is nothing you shall do for me. Bumping from existing 1.4.8+dfsg-3 to the lasted v1.4x like 1.4.10 might be reasonable and easier to request. But I can ask for zstd v1.5.2 in another release branach like Debian/experimental. About DFSG see: https://wiki.debian.org/DFSGLicenses > > My second question: > > As your changes where accepted for upcoming Linux v5.17... > > Do you plan Git branches for... > > Linux v5.16 (is [6] up2date with changes in v5.17?)... > > ...or even Linux v5.15 LTS? > > These changes landed in v5.16. I'm not planning on backporting > these changes to any older kernel version myself. > Right - backporting to v5.15 was my real question as this is LTS. > But, I am hoping to update to the latest zstd in either v5.18 or > v5.19. I'm a bit busy currently, but I just got a tentative volunteer > to update the kernel to v1.5.2, and more importantly test the > update. > Nice plans. Keep me in CC. Just for the records: v1.4.10 was tagged 8 days ago. - Sedat - [1] https://github.com/facebook/zstd/tags [2] https://github.com/facebook/zstd/releases/tag/v1.4.10 > Best, > Nick Terrell > > [0] https://github.com/facebook/zstd/tree/v1.4.10 > > > Thanks. > > > > Regards, > > - Sedat - > > > > [1] https://github.com/facebook/zstd/releases > > [2] https://github.com/facebook/zstd/tags > > [3] https://github.com/facebook/zstd/releases/tag/v1.4.9 > > [4] https://packages.debian.org/zstd > > [5] https://github.com/terrelln/linux/branches > > [6] https://github.com/terrelln/linux/commits/zstd-1.4.10 > > > >> This PR includes 5 commits that update the zstd library version: > >> > >> 1. Adds a new kernel-style wrapper around zstd. This wrapper API > >> is functionally equivalent to the subset of the current zstd API that is > >> currently used. The wrapper API changes to be kernel style so that the symbols > >> don't collide with zstd's symbols. The update to zstd-1.4.10 maintains the same > >> API and preserves the semantics, so that none of the callers need to be > >> updated. All callers are updated in the commit, because there are zero > >> functional changes. > >> 2. Adds an indirection for `lib/decompress_unzstd.c` so it > >> doesn't depend on the layout of `lib/zstd/` to include every source file. > >> This allows the next patch to be automatically generated. > >> 3. Imports the zstd-1.4.10 source code. This commit is automatically generated > >> from upstream zstd (https://github.com/facebook/zstd). > >> 4. Adds me (terrelln@xxxxxx) as the maintainer of `lib/zstd`. > >> 5. Fixes a newly added build warning for clang. > >> > >> The discussion around this patchset has been pretty long, so I've included a > >> FAQ-style summary of the history of the patchset, and why we are taking this > >> approach. > >> > >> Why do we need to update? > >> ------------------------- > >> > >> The zstd version in the kernel is based off of zstd-1.3.1, which is was released > >> August 20, 2017. Since then zstd has seen many bug fixes and performance > >> improvements. And, importantly, upstream zstd is continuously fuzzed by OSS-Fuzz, > >> and bug fixes aren't backported to older versions. So the only way to sanely get > >> these fixes is to keep up to date with upstream zstd. There are no known security > >> issues that affect the kernel, but we need to be able to update in case there > >> are. And while there are no known security issues, there are relevant bug fixes. > >> For example the problem with large kernel decompression has been fixed upstream > >> for over 2 years https://lkml.org/lkml/2020/9/29/27. > >> > >> Additionally the performance improvements for kernel use cases are significant. > >> Measured for x86_64 on my Intel i9-9900k @ 3.6 GHz: > >> > >> - BtrFS zstd compression at levels 1 and 3 is 5% faster > >> - BtrFS zstd decompression+read is 15% faster > >> - SquashFS zstd decompression+read is 15% faster > >> - F2FS zstd compression+write at level 3 is 8% faster > >> - F2FS zstd decompression+read is 20% faster > >> - ZRAM decompression+read is 30% faster > >> - Kernel zstd decompression is 35% faster > >> - Initramfs zstd decompression+build is 5% faster > >> > >> On top of this, there are significant performance improvements coming down the > >> line in the next zstd release, and the new automated update patch generation > >> will allow us to pull them easily. > >> > >> How is the update patch generated? > >> ---------------------------------- > >> > >> The first two patches are preparation for updating the zstd version. Then the > >> 3rd patch in the series imports upstream zstd into the kernel. This patch is > >> automatically generated from upstream. A script makes the necessary changes and > >> imports it into the kernel. The changes are: > >> > >> - Replace all libc dependencies with kernel replacements and rewrite includes. > >> - Remove unncessary portability macros like: #if defined(_MSC_VER). > >> - Use the kernel xxhash instead of bundling it. > >> > >> This automation gets tested every commit by upstream's continuous integration. > >> When we cut a new zstd release, we will submit a patch to the kernel to update > >> the zstd version in the kernel. > >> > >> The automated process makes it easy to keep the kernel version of zstd up to > >> date. The current zstd in the kernel shares the guts of the code, but has a lot > >> of API and minor changes to work in the kernel. This is because at the time > >> upstream zstd was not ready to be used in the kernel envrionment as-is. But, > >> since then upstream zstd has evolved to support being used in the kernel as-is. > >> > >> Why are we updating in one big patch? > >> ------------------------------------- > >> > >> The 3rd patch in the series is very large. This is because it is restructuring > >> the code, so it both deletes the existing zstd, and re-adds the new structure. > >> Future updates will be directly proportional to the changes in upstream zstd > >> since the last import. They will admittidly be large, as zstd is an actively > >> developed project, and has hundreds of commits between every release. However, > >> there is no other great alternative. > >> > >> One option ruled out is to replay every upstream zstd commit. This is not feasible > >> for several reasons: > >> - There are over 3500 upstream commits since the zstd version in the kernel. > >> - The automation to automatically generate the kernel update was only added recently, > >> so older commits cannot easily be imported. > >> - Not every upstream zstd commit builds. > >> - Only zstd releases are "supported", and individual commits may have bugs that were > >> fixed before a release. > >> > >> Another option to reduce the patch size would be to first reorganize to the new > >> file structure, and then apply the patch. However, the current kernel zstd is formatted > >> with clang-format to be more "kernel-like". But, the new method imports zstd as-is, > >> without additional formatting, to allow for closer correlation with upstream, and > >> easier debugging. So the patch wouldn't be any smaller. > >> > >> It also doesn't make sense to import upstream zstd commit by commit going > >> forward. Upstream zstd doesn't support production use cases running of the > >> development branch. We have a lot of post-commit fuzzing that catches many bugs, > >> so indiviudal commits may be buggy, but fixed before a release. So going forward, > >> I intend to import every (important) zstd release into the Kernel. > >> > >> So, while it isn't ideal, updating in one big patch is the only patch I see forward. > >> > >> Who is responsible for this code? > >> --------------------------------- > >> > >> I am. This patchset adds me as the maintainer for zstd. Previously, there was no tree > >> for zstd patches. Because of that, there were several patches that either got ignored, > >> or took a long time to merge, since it wasn't clear which tree should pick them up. > >> I'm officially stepping up as maintainer, and setting up my tree as the path through > >> which zstd patches get merged. I'll make sure that patches to the kernel zstd get > >> ported upstream, so they aren't erased when the next version update happens. > >> > >> How is this code tested? > >> ------------------------ > >> > >> I tested every caller of zstd on x86_64 (BtrFS, ZRAM, SquashFS, F2FS, Kernel, > >> InitRAMFS). I also tested Kernel & InitRAMFS on i386 and aarch64. I checked both > >> performance and correctness. > >> > >> Also, thanks to many people in the community who have tested these patches locally. > >> If you have tested the patches, please reply with a Tested-By so I can collect them > >> for the PR I will send to Linus. > >> > >> Lastly, this code will bake in linux-next before being merged into v5.16. > >> > >> Why update to zstd-1.4.10 when zstd-1.5.0 has been released? > >> ------------------------------------------------------------ > >> > >> This patchset has been outstanding since 2020, and zstd-1.4.10 was the latest > >> release when it was created. Since the update patch is automatically generated > >> from upstream, I could generate it from zstd-1.5.0. However, there were some > >> large stack usage regressions in zstd-1.5.0, and are only fixed in the latest > >> development branch. And the latest development branch contains some new code that > >> needs to bake in the fuzzer before I would feel comfortable releasing to the > >> kernel. > >> > >> Once this patchset has been merged, and we've released zstd-1.5.1, we can update > >> the kernel to zstd-1.5.1, and exercise the update process. > >> > >> You may notice that zstd-1.4.10 doesn't exist upstream. This release is an > >> artifical release based off of zstd-1.4.9, with some fixes for the kernel > >> backported from the development branch. I will tag the zstd-1.4.10 release after > >> this patchset is merged, so the Linux Kernel is running a known version of zstd > >> that can be debugged upstream. > >> > >> Why was a wrapper API added? > >> ---------------------------- > >> > >> The first versions of this patchset migrated the kernel to the upstream zstd > >> API. It first added a shim API that supported the new upstream API with the old > >> code, then updated callers to use the new shim API, then transitioned to the > >> new code and deleted the shim API. However, Cristoph Hellwig suggested that we > >> transition to a kernel style API, and hide zstd's upstream API behind that. > >> This is because zstd's upstream API is supports many other use cases, and does > >> not follow the kernel style guide, while the kernel API is focused on the > >> kernel's use cases, and follows the kernel style guide. > >> > >> Where is the previous discussion? > >> --------------------------------- > >> > >> Links for the discussions of the previous versions of the patch set. > >> The largest changes in the design of the patchset are driven by the discussions > >> in V11, V5, and V1. Sorry for the mix of links, I couldn't find most of the the > >> threads on lkml.org. > >> > >> V12: https://www.spinics.net/lists/linux-crypto/msg58189.html > >> V11: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@xxxxxxxxx/ > >> V10: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@xxxxxxxxx/ > >> V9: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@xxxxxxxxx/ > >> V8: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@xxxxxxxxx/ > >> V7: https://lkml.org/lkml/2020/12/3/1195 > >> V6: https://lkml.org/lkml/2020/12/2/1245 > >> V5: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@xxxxxxxxx/ > >> V4: https://www.spinics.net/lists/linux-btrfs/msg105783.html > >> V3: https://lkml.org/lkml/2020/9/23/1074 > >> V2: https://www.spinics.net/lists/linux-btrfs/msg105505.html > >> V1: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@xxxxxxxxx/ > >> > >> Signed-off-by: Nick Terrell <terrelln@xxxxxx> > >> Tested By: Paul Jones <paul@xxxxxxxxxxxxxxx> > >> Tested-by: Oleksandr Natalenko <oleksandr@xxxxxxxxxxxxxx> > >> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> # LLVM/Clang v13.0.0 on x86-64 > >> Tested-by: Jean-Denis Girard <jd.girard@xxxxxxxxx> > >> > >> ---------------------------------------------------------------- > >> Nathan Chancellor (1): > >> lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical > >> > >> Nick Terrell (4): > >> lib: zstd: Add kernel-specific API > >> lib: zstd: Add decompress_sources.h for decompress_unzstd > >> lib: zstd: Upgrade to latest upstream zstd version 1.4.10 > >> MAINTAINERS: Add maintainer entry for zstd > >> > >> MAINTAINERS | 12 + > >> crypto/zstd.c | 28 +- > >> fs/btrfs/zstd.c | 68 +- > >> fs/f2fs/compress.c | 56 +- > >> fs/f2fs/super.c | 2 +- > >> fs/pstore/platform.c | 2 +- > >> fs/squashfs/zstd_wrapper.c | 16 +- > >> include/linux/zstd.h | 1252 ++---- > >> include/linux/zstd_errors.h | 77 + > >> include/linux/zstd_lib.h | 2432 +++++++++++ > >> lib/decompress_unzstd.c | 48 +- > >> lib/zstd/Makefile | 46 +- > >> lib/zstd/bitstream.h | 380 -- > >> lib/zstd/common/bitstream.h | 437 ++ > >> lib/zstd/common/compiler.h | 170 + > >> lib/zstd/common/cpu.h | 194 + > >> lib/zstd/common/debug.c | 24 + > >> lib/zstd/common/debug.h | 101 + > >> lib/zstd/common/entropy_common.c | 357 ++ > >> lib/zstd/common/error_private.c | 56 + > >> lib/zstd/common/error_private.h | 66 + > >> lib/zstd/common/fse.h | 710 ++++ > >> lib/zstd/common/fse_decompress.c | 390 ++ > >> lib/zstd/common/huf.h | 356 ++ > >> lib/zstd/common/mem.h | 259 ++ > >> lib/zstd/common/zstd_common.c | 83 + > >> lib/zstd/common/zstd_deps.h | 125 + > >> lib/zstd/common/zstd_internal.h | 450 +++ > >> lib/zstd/compress.c | 3485 ---------------- > >> lib/zstd/compress/fse_compress.c | 625 +++ > >> lib/zstd/compress/hist.c | 165 + > >> lib/zstd/compress/hist.h | 75 + > >> lib/zstd/compress/huf_compress.c | 905 +++++ > >> lib/zstd/compress/zstd_compress.c | 5109 ++++++++++++++++++++++++ > >> lib/zstd/compress/zstd_compress_internal.h | 1188 ++++++ > >> lib/zstd/compress/zstd_compress_literals.c | 158 + > >> lib/zstd/compress/zstd_compress_literals.h | 29 + > >> lib/zstd/compress/zstd_compress_sequences.c | 439 ++ > >> lib/zstd/compress/zstd_compress_sequences.h | 54 + > >> lib/zstd/compress/zstd_compress_superblock.c | 850 ++++ > >> lib/zstd/compress/zstd_compress_superblock.h | 32 + > >> lib/zstd/compress/zstd_cwksp.h | 482 +++ > >> lib/zstd/compress/zstd_double_fast.c | 519 +++ > >> lib/zstd/compress/zstd_double_fast.h | 32 + > >> lib/zstd/compress/zstd_fast.c | 496 +++ > >> lib/zstd/compress/zstd_fast.h | 31 + > >> lib/zstd/compress/zstd_lazy.c | 1414 +++++++ > >> lib/zstd/compress/zstd_lazy.h | 81 + > >> lib/zstd/compress/zstd_ldm.c | 686 ++++ > >> lib/zstd/compress/zstd_ldm.h | 110 + > >> lib/zstd/compress/zstd_ldm_geartab.h | 103 + > >> lib/zstd/compress/zstd_opt.c | 1346 +++++++ > >> lib/zstd/compress/zstd_opt.h | 50 + > >> lib/zstd/decompress.c | 2531 ------------ > >> lib/zstd/decompress/huf_decompress.c | 1206 ++++++ > >> lib/zstd/decompress/zstd_ddict.c | 241 ++ > >> lib/zstd/decompress/zstd_ddict.h | 44 + > >> lib/zstd/decompress/zstd_decompress.c | 2085 ++++++++++ > >> lib/zstd/decompress/zstd_decompress_block.c | 1540 +++++++ > >> lib/zstd/decompress/zstd_decompress_block.h | 62 + > >> lib/zstd/decompress/zstd_decompress_internal.h | 202 + > >> lib/zstd/decompress_sources.h | 28 + > >> lib/zstd/entropy_common.c | 243 -- > >> lib/zstd/error_private.h | 53 - > >> lib/zstd/fse.h | 575 --- > >> lib/zstd/fse_compress.c | 795 ---- > >> lib/zstd/fse_decompress.c | 325 -- > >> lib/zstd/huf.h | 212 - > >> lib/zstd/huf_compress.c | 773 ---- > >> lib/zstd/huf_decompress.c | 960 ----- > >> lib/zstd/mem.h | 151 - > >> lib/zstd/zstd_common.c | 75 - > >> lib/zstd/zstd_compress_module.c | 160 + > >> lib/zstd/zstd_decompress_module.c | 105 + > >> lib/zstd/zstd_internal.h | 273 -- > >> lib/zstd/zstd_opt.h | 1014 ----- > >> 76 files changed, 27373 insertions(+), 12941 deletions(-) > >> create mode 100644 include/linux/zstd_errors.h > >> create mode 100644 include/linux/zstd_lib.h > >> delete mode 100644 lib/zstd/bitstream.h > >> create mode 100644 lib/zstd/common/bitstream.h > >> create mode 100644 lib/zstd/common/compiler.h > >> create mode 100644 lib/zstd/common/cpu.h > >> create mode 100644 lib/zstd/common/debug.c > >> create mode 100644 lib/zstd/common/debug.h > >> create mode 100644 lib/zstd/common/entropy_common.c > >> create mode 100644 lib/zstd/common/error_private.c > >> create mode 100644 lib/zstd/common/error_private.h > >> create mode 100644 lib/zstd/common/fse.h > >> create mode 100644 lib/zstd/common/fse_decompress.c > >> create mode 100644 lib/zstd/common/huf.h > >> create mode 100644 lib/zstd/common/mem.h > >> create mode 100644 lib/zstd/common/zstd_common.c > >> create mode 100644 lib/zstd/common/zstd_deps.h > >> create mode 100644 lib/zstd/common/zstd_internal.h > >> delete mode 100644 lib/zstd/compress.c > >> create mode 100644 lib/zstd/compress/fse_compress.c > >> create mode 100644 lib/zstd/compress/hist.c > >> create mode 100644 lib/zstd/compress/hist.h > >> create mode 100644 lib/zstd/compress/huf_compress.c > >> create mode 100644 lib/zstd/compress/zstd_compress.c > >> create mode 100644 lib/zstd/compress/zstd_compress_internal.h > >> create mode 100644 lib/zstd/compress/zstd_compress_literals.c > >> create mode 100644 lib/zstd/compress/zstd_compress_literals.h > >> create mode 100644 lib/zstd/compress/zstd_compress_sequences.c > >> create mode 100644 lib/zstd/compress/zstd_compress_sequences.h > >> create mode 100644 lib/zstd/compress/zstd_compress_superblock.c > >> create mode 100644 lib/zstd/compress/zstd_compress_superblock.h > >> create mode 100644 lib/zstd/compress/zstd_cwksp.h > >> create mode 100644 lib/zstd/compress/zstd_double_fast.c > >> create mode 100644 lib/zstd/compress/zstd_double_fast.h > >> create mode 100644 lib/zstd/compress/zstd_fast.c > >> create mode 100644 lib/zstd/compress/zstd_fast.h > >> create mode 100644 lib/zstd/compress/zstd_lazy.c > >> create mode 100644 lib/zstd/compress/zstd_lazy.h > >> create mode 100644 lib/zstd/compress/zstd_ldm.c > >> create mode 100644 lib/zstd/compress/zstd_ldm.h > >> create mode 100644 lib/zstd/compress/zstd_ldm_geartab.h > >> create mode 100644 lib/zstd/compress/zstd_opt.c > >> create mode 100644 lib/zstd/compress/zstd_opt.h > >> delete mode 100644 lib/zstd/decompress.c > >> create mode 100644 lib/zstd/decompress/huf_decompress.c > >> create mode 100644 lib/zstd/decompress/zstd_ddict.c > >> create mode 100644 lib/zstd/decompress/zstd_ddict.h > >> create mode 100644 lib/zstd/decompress/zstd_decompress.c > >> create mode 100644 lib/zstd/decompress/zstd_decompress_block.c > >> create mode 100644 lib/zstd/decompress/zstd_decompress_block.h > >> create mode 100644 lib/zstd/decompress/zstd_decompress_internal.h > >> create mode 100644 lib/zstd/decompress_sources.h > >> delete mode 100644 lib/zstd/entropy_common.c > >> delete mode 100644 lib/zstd/error_private.h > >> delete mode 100644 lib/zstd/fse.h > >> delete mode 100644 lib/zstd/fse_compress.c > >> delete mode 100644 lib/zstd/fse_decompress.c > >> delete mode 100644 lib/zstd/huf.h > >> delete mode 100644 lib/zstd/huf_compress.c > >> delete mode 100644 lib/zstd/huf_decompress.c > >> delete mode 100644 lib/zstd/mem.h > >> delete mode 100644 lib/zstd/zstd_common.c > >> create mode 100644 lib/zstd/zstd_compress_module.c > >> create mode 100644 lib/zstd/zstd_decompress_module.c > >> delete mode 100644 lib/zstd/zstd_internal.h > >> delete mode 100644 lib/zstd/zstd_opt.h >
