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Linus Torvalds 4c388a8e74 zstd fixes for v5.16-rc1
Fix stack usage on parisc & improve code size bloat
 
 This PR contains 3 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 commit 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.
 
 [0] https://lore.kernel.org/linux-mm/202111120312.833wII4i-lkp@intel.com/T/
 [1] https://lkml.org/lkml/2021/11/15/710
 [2] https://lkml.org/lkml/2021/11/14/189
 [3] https://github.com/facebook/zstd/issues/2867
 
 Link: https://lore.kernel.org/r/20211117014949.1169186-1-nickrterrell@gmail.com/
 Link: https://lore.kernel.org/r/20211117201459.1194876-1-nickrterrell@gmail.com/
 
 Signed-off-by: Nick Terrell <terrelln@fb.com>
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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
2021-11-18 17:09:05 -08:00
arch parisc bug and warning fixes and wire up futex_waitv 2021-11-18 12:13:24 -08:00
block blk-mq: fix filesystem I/O request allocation 2021-11-12 09:31:13 -07:00
certs certs: Add support for using elliptic curve keys for signing modules 2021-08-23 19:55:42 +03:00
crypto Update to zstd-1.4.10 2021-11-13 15:32:30 -08:00
Documentation Power management fixes for 5.16-rc2 2021-11-18 14:46:28 -08:00
drivers Thermal control fixes for 5.16-rc2 2021-11-18 14:52:24 -08:00
fs for-5.16-rc1-tag 2021-11-18 12:41:14 -08:00
include Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
init kbuild: Fix -Wimplicit-fallthrough=5 error for GCC 5.x and 6.x 2021-11-14 18:59:49 -08:00
ipc ipc/ipc_sysctl.c: remove fallback for !CONFIG_PROC_SYSCTL 2021-11-09 10:02:53 -08:00
kernel Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
lib zstd fixes for v5.16-rc1 2021-11-18 17:09:05 -08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm Revert "mm: shmem: don't truncate page if memory failure happens" 2021-11-13 12:03:03 -08:00
net Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
samples samples/bpf: Fix build error due to -isystem removal 2021-11-15 20:37:20 -08:00
scripts coccinelle patches for 5.16-rc1 2021-11-13 10:45:17 -08:00
security net,lsm,selinux: revert the security_sctp_assoc_established() hook 2021-11-14 12:21:53 +00:00
sound sound fixes for 5.16-rc1 2021-11-12 12:17:30 -08:00
tools Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
usr initramfs: Check timestamp to prevent broken cpio archive 2021-10-24 13:48:40 +09:00
virt Merge branch 'kvm-5.16-fixes' into kvm-master 2021-11-18 02:11:57 -05:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap Merge branch 'akpm' (patches from Andrew) 2021-11-09 10:11:53 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Networking fixes for 5.16-rc2, including fixes from bpf, mac80211. 2021-11-18 12:54:24 -08:00
Makefile Linux 5.16-rc1 2021-11-14 13:56:52 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.