On October 10, 2017 2:22:42 PM PDT, Nick Terrell <terre...@fb.com> wrote: >Hi, > >This patch set adds support for a ZSTD-compressed kernel and ramdisk >images in the kernel boot process. It only integrates the support with >x86, though the first patch is generic to all architectures. > >Zstandard requires slightly more memory during the kernel decompression >on x86 (192 KB vs 64 KB), and the memory usage is independent of the >window size. > >Zstandard requires memory proprortional to the window size used during >compression for decompressing the ramdisk image, since streaming mode >is >used. Newer versions of zstd (1.3.2+) list the window size of a file >with `zstd -lv <file>'. The absolute maximum amount of memory required >is just over 8 MB. > >Thanks, >Nick Terrell > >Nick Terrell (2): > lib: Add support for ZSTD-compressed kernel > x86: Add support for ZSTD-compressed kernel > > Documentation/x86/boot.txt | 6 +- > arch/x86/Kconfig | 1 + > arch/x86/boot/compressed/Makefile | 5 +- > arch/x86/boot/compressed/misc.c | 4 + > arch/x86/boot/header.S | 8 +- > arch/x86/include/asm/boot.h | 6 +- > include/linux/decompress/unzstd.h | 26 +++ > init/Kconfig | 14 +- > lib/Kconfig | 4 + > lib/Makefile | 1 + > lib/decompress.c | 5 + >lib/decompress_unzstd.c | 341 >++++++++++++++++++++++++++++++++++++++ > lib/xxhash.c | 21 ++- > lib/zstd/decompress.c | 2 + > lib/zstd/fse_decompress.c | 9 +- > scripts/Makefile.lib | 15 ++ > usr/Kconfig | 22 +++ > 17 files changed, 465 insertions(+), 25 deletions(-) > create mode 100644 include/linux/decompress/unzstd.h > create mode 100644 lib/decompress_unzstd.c
And, pray tell, what are the actual results? What is the trade-off of kernel size versus decompression performance versus the other algorithms that we already support? Adding algorithms for their own sake is a bad thing not a good thing. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
