mainlining shenanigans
c6425702f2
A customer reported rcu stalls and softlockup warnings on a computer with many CPU cores and many many more IO threads trying to write to a filesystem that is totally out of space. Subsequent analysis pointed to the many many IO threads calling xfs_flush_inodes -> sync_inodes_sb, which causes a lot of wb_writeback_work to be queued. The writeback worker spends so much time trying to wake the many many threads waiting for writeback completion that it trips the softlockup detector, and (in this case) the system automatically reboots. In addition, they complain that the lengthy xfs_flush_inodes scan traps all of those threads in uninterruptible sleep, which hampers their ability to kill the program or do anything else to escape the situation. If there's thousands of threads trying to write to files on a full filesystem, each of those threads will start separate copies of the inode flush scan. This is kind of pointless since we only need one scan, so rate limit the inode flush. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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.