#
4922f092 |
| 14-Dec-2021 |
Jason Gunthorpe <jgg@nvidia.com> |
Merge tag 'v5.16-rc5' into rdma.git for-next
Required due to dependencies in following patches.
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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Revision tags: v5.15.8 |
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#
6773cc31 |
| 13-Dec-2021 |
Ingo Molnar <mingo@kernel.org> |
Merge tag 'v5.16-rc5' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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#
a7fb920b |
| 10-Dec-2021 |
Jonathan Corbet <corbet@lwn.net> |
Merge tag 'v5.16-rc4' into docs-next
I have a couple of fixes for warnings introduced after -rc1; catch up to -rc4 so that the fixes have something to fix.
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#
86329873 |
| 09-Dec-2021 |
Daniel Lezcano <daniel.lezcano@linaro.org> |
Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next
"Add optional variant of of_reset_control_get_exclusive(). If the requested reset is not
Merge branch 'reset/of-get-optional-exclusive' of git://git.pengutronix.de/pza/linux into timers/drivers/next
"Add optional variant of of_reset_control_get_exclusive(). If the requested reset is not specified in the device tree, this function returns NULL instead of an error."
This dependency is needed for the Generic Timer Module (a.k.a OSTM) support for RZ/G2L.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
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Revision tags: v5.15.7 |
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#
4383cfa1 |
| 07-Dec-2021 |
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> |
Merge tag 'v5.16-rc4' into media_tree
Linux 5.16-rc4
* tag 'v5.16-rc4': (984 commits) Linux 5.16-rc4 KVM: SVM: Do not terminate SEV-ES guests on GHCB validation failure KVM: SEV: Fall back to
Merge tag 'v5.16-rc4' into media_tree
Linux 5.16-rc4
* tag 'v5.16-rc4': (984 commits) Linux 5.16-rc4 KVM: SVM: Do not terminate SEV-ES guests on GHCB validation failure KVM: SEV: Fall back to vmalloc for SEV-ES scratch area if necessary KVM: SEV: Return appropriate error codes if SEV-ES scratch setup fails parisc: Mark cr16 CPU clocksource unstable on all SMP machines parisc: Fix "make install" on newer debian releases sched/uclamp: Fix rq->uclamp_max not set on first enqueue preempt/dynamic: Fix setup_preempt_mode() return value cifs: avoid use of dstaddr as key for fscache client cookie cifs: add server conn_id to fscache client cookie cifs: wait for tcon resource_id before getting fscache super cifs: fix missed refcounting of ipc tcon x86/xen: Add xenpv_restore_regs_and_return_to_usermode() x86/entry: Use the correct fence macro after swapgs in kernel CR3 fget: check that the fd still exists after getting a ref to it x86/entry: Add a fence for kernel entry SWAPGS in paranoid_entry() x86/sev: Fix SEV-ES INS/OUTS instructions for word, dword, and qword powercap: DTPM: Drop unused local variable from init_dtpm() io-wq: don't retry task_work creation failure on fatal conditions serial: 8250_bcm7271: UART errors after resuming from S2 ...
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#
83b965d1 |
| 06-Dec-2021 |
Rob Clark <robdclark@chromium.org> |
Merge remote-tracking branch 'drm/drm-next' into msm-next-staging
Backmerge drm-next to pull in:
8f59ee9a570c ("drm/msm/dsi: Adjust probe order")
Signed-off-by: Rob Clark <robdclark@chromium.org>
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Revision tags: v5.15.6 |
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#
4d012040 |
| 29-Nov-2021 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
Merge 5.16-rc3 into usb-next
We need the USB driver fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
24cd7197 |
| 29-Nov-2021 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
Merge 5.16-rc3 into staging-next
We need the staging driver fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
5d331b59 |
| 29-Nov-2021 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
Merge 5.16-rc3 into char-misc-next
We need the char/misc fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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#
2448eab4 |
| 26-Nov-2021 |
Linus Walleij <linus.walleij@linaro.org> |
Merge tag 'v5.16-rc2' into devel
Linux 5.16-rc2 is needed because nonurgent fixes headed for next are strongly textually dependent on a fix that was applied for rc2.
Signed-off-by: Linus Walleij <l
Merge tag 'v5.16-rc2' into devel
Linux 5.16-rc2 is needed because nonurgent fixes headed for next are strongly textually dependent on a fix that was applied for rc2.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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#
93d5404e |
| 26-Nov-2021 |
Jakub Kicinski <kuba@kernel.org> |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/ipa/ipa_main.c 8afc7e471ad3 ("net: ipa: separate disabling setup from modem stop") 76b5fbcd6b47 ("net: ipa: kill ipa_mo
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
drivers/net/ipa/ipa_main.c 8afc7e471ad3 ("net: ipa: separate disabling setup from modem stop") 76b5fbcd6b47 ("net: ipa: kill ipa_modem_init()")
Duplicated include, drop one.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Revision tags: v5.15.5 |
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#
448cc2fb |
| 22-Nov-2021 |
Jani Nikula <jani.nikula@intel.com> |
Merge drm/drm-next into drm-intel-next
Sync up with drm-next to get v5.16-rc2.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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#
8626afb1 |
| 22-Nov-2021 |
Tvrtko Ursulin <tvrtko.ursulin@intel.com> |
Merge drm/drm-next into drm-intel-gt-next
Thomas needs the dma_resv_for_each_fence API for i915/ttm async migration work.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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Revision tags: v5.15.4 |
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#
4c388a8e |
| 18-Nov-2021 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'zstd-for-linus-5.16-rc1' of git://github.com/terrelln/linux
Pull zstd fixes from Nick Terrell: "Fix stack usage on parisc & improve code size bloat
This contains three commits:
1.
Merge tag 'zstd-for-linus-5.16-rc1' of git://github.com/terrelln/linux
Pull zstd fixes from Nick Terrell: "Fix stack usage on parisc & improve code size bloat
This contains three commits:
1. Fixes a minor unused variable warning reported by Kernel test robot [0].
2. Improves the reported code bloat (-88KB / 374KB) [1] by outlining some functions that are unlikely to be used in performance sensitive workloads.
3. Fixes the reported excess stack usage on parisc [2] by removing -O3 from zstd's compilation flags. -O3 triggered bugs in the hppa-linux-gnu gcc-8 compiler. -O2 performance is acceptable: neutral compression, about -1% decompression speed. We also reduce code bloat (-105KB / 374KB).
After this our code bloat is cut from 374KB to 105KB with gcc-11. If we wanted to cut the remaining 105KB we'd likely have to trade signicant performance, so I want to say that this is enough for now.
We should be able to get further gains without sacrificing speed, but that will take some significant optimization effort, and isn't suitable for a quick fix. I've opened an upstream issue [3] to track the code size, and try to avoid future regressions, and improve it in the long term"
Link: https://lore.kernel.org/linux-mm/202111120312.833wII4i-lkp@intel.com/T/ [0] Link: https://lkml.org/lkml/2021/11/15/710 [1] Link: https://lkml.org/lkml/2021/11/14/189 [2] Link: https://github.com/facebook/zstd/issues/2867 [3] Link: https://lore.kernel.org/r/20211117014949.1169186-1-nickrterrell@gmail.com/ Link: https://lore.kernel.org/r/20211117201459.1194876-1-nickrterrell@gmail.com/
* tag 'zstd-for-linus-5.16-rc1' of git://github.com/terrelln/linux: lib: zstd: Don't add -O3 to cflags lib: zstd: Don't inline functions in zstd_opt.c lib: zstd: Fix unused variable warning
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Revision tags: v5.15.3 |
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#
1974990c |
| 15-Nov-2021 |
Nick Terrell <terrelln@fb.com> |
lib: zstd: Don't inline functions in zstd_opt.c
`zstd_opt.c` contains the match finder for the highest compression levels. These levels are already very slow, and are unlikely to be used in the kern
lib: zstd: Don't inline functions in zstd_opt.c
`zstd_opt.c` contains the match finder for the highest compression levels. These levels are already very slow, and are unlikely to be used in the kernel. If they are used, they shouldn't be used in latency sensitive workloads, so slowing them down shouldn't be a big deal.
This saves 188 KB of the 288 KB regression reported by Geert Uytterhoeven [0]. I've also opened an issue upstream [1] so that we can properly tackle the code size issue in `zstd_opt.c` for all users, and can hopefully remove this hack in the next zstd version we import.
Bloat-o-meter output on x86-64:
``` > ../scripts/bloat-o-meter vmlinux.old vmlinux add/remove: 6/5 grow/shrink: 1/9 up/down: 16673/-209939 (-193266) Function old new delta ZSTD_compressBlock_opt_generic.constprop - 7559 +7559 ZSTD_insertBtAndGetAllMatches - 6304 +6304 ZSTD_insertBt1 - 1731 +1731 ZSTD_storeSeq - 693 +693 ZSTD_BtGetAllMatches - 255 +255 ZSTD_updateRep - 128 +128 ZSTD_updateTree 96 99 +3 ZSTD_insertAndFindFirstIndexHash3 81 - -81 ZSTD_setBasePrices.constprop 98 - -98 ZSTD_litLengthPrice.constprop 138 - -138 ZSTD_count 362 181 -181 ZSTD_count_2segments 1407 938 -469 ZSTD_insertBt1.constprop 2689 - -2689 ZSTD_compressBlock_btultra2 19990 423 -19567 ZSTD_compressBlock_btultra 19633 15 -19618 ZSTD_initStats_ultra 19825 - -19825 ZSTD_compressBlock_btopt 20374 12 -20362 ZSTD_compressBlock_btopt_extDict 29984 12 -29972 ZSTD_compressBlock_btultra_extDict 30718 15 -30703 ZSTD_compressBlock_btopt_dictMatchState 32689 12 -32677 ZSTD_compressBlock_btultra_dictMatchState 33574 15 -33559 Total: Before=6611828, After=6418562, chg -2.92% ```
[0] https://lkml.org/lkml/2021/11/14/189 [1] https://github.com/facebook/zstd/issues/2862
Link: https://lore.kernel.org/r/20211117014949.1169186-3-nickrterrell@gmail.com/ Link: https://lore.kernel.org/r/20211117201459.1194876-3-nickrterrell@gmail.com/
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Nick Terrell <terrelln@fb.com>
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#
50fc2494 |
| 18-Nov-2021 |
Jakub Kicinski <kuba@kernel.org> |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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#
a713ca23 |
| 18-Nov-2021 |
Thomas Zimmermann <tzimmermann@suse.de> |
Merge drm/drm-next into drm-misc-next
Backmerging from drm/drm-next for v5.16-rc1.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
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#
467dd91e |
| 16-Nov-2021 |
Maxime Ripard <maxime@cerno.tech> |
Merge drm/drm-fixes into drm-misc-fixes
We need -rc1 to address a breakage in drm/scheduler affecting panfrost.
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
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#
c8c10954 |
| 13-Nov-2021 |
Linus Torvalds <torvalds@linux-foundation.org> |
Merge tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux
Pull zstd update from Nick Terrell: "Update to zstd-1.4.10.
Add myself as the maintainer of zstd and update the zstd version i
Merge tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux
Pull zstd update from Nick Terrell: "Update to zstd-1.4.10.
Add myself as the maintainer of zstd and update the zstd version in the kernel, which is now 4 years out of date, to a much more recent 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.
This includes 5 commits that update the zstd library version:
- 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.
- 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.
- Imports the zstd-1.4.10 source code. This commit is automatically generated from upstream zstd (https://github.com/facebook/zstd).
- Adds me (terrelln@fb.com) as the maintainer of `lib/zstd`.
- 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 [1]
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.
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 below. 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"
Link: https://lkml.org/lkml/2020/9/29/27 [1] Link: https://www.spinics.net/lists/linux-crypto/msg58189.html [v12] Link: https://lore.kernel.org/linux-btrfs/20210430013157.747152-1-nickrterrell@gmail.com/ [v11] Link: https://lore.kernel.org/lkml/20210426234621.870684-2-nickrterrell@gmail.com/ [v10] Link: https://lore.kernel.org/linux-btrfs/20210330225112.496213-1-nickrterrell@gmail.com/ [v9] Link: https://lore.kernel.org/linux-f2fs-devel/20210326191859.1542272-1-nickrterrell@gmail.com/ [v8] Link: https://lkml.org/lkml/2020/12/3/1195 [v7] Link: https://lkml.org/lkml/2020/12/2/1245 [v6] Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v5] Link: https://www.spinics.net/lists/linux-btrfs/msg105783.html [v4] Link: https://lkml.org/lkml/2020/9/23/1074 [v3] Link: https://www.spinics.net/lists/linux-btrfs/msg105505.html [v2] Link: https://lore.kernel.org/linux-btrfs/20200916034307.2092020-1-nickrterrell@gmail.com/ [v1] Signed-off-by: Nick Terrell <terrelln@fb.com> Tested By: Paul Jones <paul@pauljones.id.au> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64 Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
* tag 'zstd-for-linus-v5.16' of git://github.com/terrelln/linux: lib: zstd: Add cast to silence clang's -Wbitwise-instead-of-logical MAINTAINERS: Add maintainer entry for zstd lib: zstd: Upgrade to latest upstream zstd version 1.4.10 lib: zstd: Add decompress_sources.h for decompress_unzstd lib: zstd: Add kernel-specific API
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Revision tags: v5.15.2, v5.15.1, v5.15, v5.14.14, v5.14.13, v5.14.12, v5.14.11, v5.14.10, v5.14.9, v5.14.8, v5.14.7, v5.14.6, v5.10.67, v5.10.66, v5.14.5, v5.14.4, v5.10.65, v5.14.3, v5.10.64, v5.14.2, v5.10.63, v5.14.1, v5.10.62, v5.14, v5.10.61, v5.10.60, v5.10.53, v5.10.52, v5.10.51, v5.10.50, v5.10.49, v5.13, v5.10.46, v5.10.43, v5.10.42, v5.10.41, v5.10.40, v5.10.39, v5.4.119, v5.10.36, v5.10.35, v5.10.34, v5.4.116, v5.10.33, v5.12, v5.10.32, v5.10.31, v5.10.30, v5.10.27, v5.10.26, v5.10.25, v5.10.24, v5.10.23, v5.10.22, v5.10.21, v5.10.20, v5.10.19, v5.4.101, v5.10.18, v5.10.17, v5.11, v5.10.16, v5.10.15, v5.10.14, v5.10, v5.8.17, v5.8.16, v5.8.15, v5.9, v5.8.14, v5.8.13, v5.8.12, v5.8.11, v5.8.10, v5.8.9 |
|
#
e0c1b49f |
| 11-Sep-2020 |
Nick Terrell <terrelln@fb.com> |
lib: zstd: Upgrade to latest upstream zstd version 1.4.10
Upgrade to the latest upstream zstd version 1.4.10.
This patch is 100% generated from upstream zstd commit 20821a46f412 [0].
This patch is
lib: zstd: Upgrade to latest upstream zstd version 1.4.10
Upgrade to the latest upstream zstd version 1.4.10.
This patch is 100% generated from upstream zstd commit 20821a46f412 [0].
This patch is very large because it is transitioning from the custom kernel zstd to using upstream directly. The new zstd follows upstreams file structure which is different. Future update patches will be much smaller because they will only contain the changes from one upstream zstd release.
As an aid for review I've created a commit [1] that shows the diff between upstream zstd as-is (which doesn't compile), and the zstd code imported in this patch. The verion of zstd in this patch is generated from upstream with changes applied by automation to replace upstreams libc dependencies, remove unnecessary portability macros, replace `/**` comments with `/*` comments, and use the kernel's xxhash instead of bundling it.
The benefits of this patch are as follows: 1. Using upstream directly with automated script to generate kernel code. This allows us to update the kernel every upstream release, so the kernel gets the latest bug fixes and performance improvements, and doesn't get 3 years out of date again. The automation and the translated code are tested every upstream commit to ensure it continues to work. 2. Upgrades from a custom zstd based on 1.3.1 to 1.4.10, getting 3 years of performance improvements and bug fixes. On x86_64 I've measured 15% faster BtrFS and SquashFS decompression+read speeds, 35% faster kernel decompression, and 30% faster ZRAM decompression+read speeds. 3. Zstd-1.4.10 supports negative compression levels, which allow zstd to match or subsume lzo's performance. 4. Maintains the same kernel-specific wrapper API, so no callers have to be modified with zstd version updates.
One concern that was brought up was stack usage. Upstream zstd had already removed most of its heavy stack usage functions, but I just removed the last functions that allocate arrays on the stack. I've measured the high water mark for both compression and decompression before and after this patch. Decompression is approximately neutral, using about 1.2KB of stack space. Compression levels up to 3 regressed from 1.4KB -> 1.6KB, and higher compression levels regressed from 1.5KB -> 2KB. We've added unit tests upstream to prevent further regression. I believe that this is a reasonable increase, and if it does end up causing problems, this commit can be cleanly reverted, because it only touches zstd.
I chose the bulk update instead of replaying upstream commits because there have been ~3500 upstream commits since the 1.3.1 release, zstd wasn't ready to be used in the kernel as-is before a month ago, and not all upstream zstd commits build. The bulk update preserves bisectablity because bugs can be bisected to the zstd version update. At that point the update can be reverted, and we can work with upstream to find and fix the bug.
Note that upstream zstd release 1.4.10 doesn't exist yet. I have cut a staging branch at 20821a46f412 [0] and will apply any changes requested to the staging branch. Once we're ready to merge this update I will cut a zstd release at the commit we merge, so we have a known zstd release in the kernel.
The implementation of the kernel API is contained in zstd_compress_module.c and zstd_decompress_module.c.
[0] https://github.com/facebook/zstd/commit/20821a46f4122f9abd7c7b245d28162dde8129c9 [1] https://github.com/terrelln/linux/commit/e0fa481d0e3df26918da0a13749740a1f6777574
Signed-off-by: Nick Terrell <terrelln@fb.com> Tested By: Paul Jones <paul@pauljones.id.au> Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM/Clang v13.0.0 on x86-64 Tested-by: Jean-Denis Girard <jd.girard@sysnux.pf>
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