Proxmox-Port/zfs
1
0
Fork 0
mirror of https://github.com/openzfs/zfs.git synced 2025-08-15 12:33:21 +00:00
Code Issues Actions 6 Packages Projects Releases Wiki Activity
master
zfs/module/zstd
History
Brian Behlendorf 152e34822b
Silence zstd large allocation warning 
Allow zstd_mempool_init() to allocate using vmem_alloc() instead
of kmem_alloc() to silence the large allocation warning on Linux
during module load when the system has a large number of CPUs.

It's not at all clear to me that scaling the allocation size with
the number of CPUs is beneficial and that should be evaluated.
But for the moment this should resolve the warning without
introducing any unexpected side effects.

Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Rob Norris <robn@despairlabs.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #17620
Closes #11557
2025-08-12 13:38:08 -07:00
..
include SPDX: license tags: BSD-3-Clause 2025-03-13 17:56:50 -07:00
lib SPDX: license tags: BSD-3-Clause OR GPL-2.0-only 2025-03-13 17:57:17 -07:00
README.md linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
zfs_zstd.c Silence zstd large allocation warning 2025-08-12 13:38:08 -07:00
zstd_sparc.c Fix cross-endian interoperability of zstd 2021-08-30 14:13:46 -07:00
zstd-in.c SPDX: license tags: BSD-3-Clause 2025-03-13 17:56:50 -07:00

README.md

ZSTD-On-ZFS Library Manual

Introduction

This subtree contains the ZSTD library used in ZFS. It is heavily cut-down by dropping any unneeded files, and combined into a single file, but otherwise is intentionally unmodified. Please do not alter the file containing the zstd library, besides upgrading to a newer ZSTD release.

Tree structure:

  • zfs_zstd.c are the actual zfs kernel module hooks.
  • lib/ contains the unmodified version of the Zstandard library
  • zstd-in.c is our template file for generating the single-file library
  • include/: This directory contains supplemental includes for platform compatibility, which are not expected to be used by ZFS elsewhere in the future. Thus we keep them private to ZSTD.

Updating ZSTD

To update ZSTD the following steps need to be taken:

  1. Grab the latest release of ZSTD.
  2. Copy the files output by the following script to module/zstd/lib/: grep include [path to zstd]/contrib/single_file_libs/zstd-in.c | awk '{ print $2 }'
  3. Remove debug.c, threading.c, and zstdmt_compress.c.
  4. Update Makefiles with resulting file lists.
  5. Follow symbol renaming notes in include/zstd_compat_wrapper.h

Altering ZSTD and breaking changes

If ZSTD made changes that break compatibility or you need to make breaking changes to the way we handle ZSTD, it is required to maintain backwards compatibility.

We already save the ZSTD version number within the block header to be used to add future compatibility checks and/or fixes. However, currently it is not actually used in such a way.