8480ed9c2b
Today the Xen ballooning is done via delayed work in a workqueue. This
might result in workqueue hangups being reported in case of large
amounts of memory are being ballooned in one go (here 16GB):
BUG: workqueue lockup - pool cpus=6 node=0 flags=0x0 nice=0 stuck for 64s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=2/256 refcnt=3
in-flight: 229:balloon_process
pending: cache_reap
workqueue events_freezable_power_: flags=0x84
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: disk_events_workfn
workqueue mm_percpu_wq: flags=0x8
pwq 12: cpus=6 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_update
pool 12: cpus=6 node=0 flags=0x0 nice=0 hung=64s workers=3 idle: 2222 43
This can easily be avoided by using a dedicated kernel thread for doing
the ballooning work.
Reported-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210827123206.15429-1-jgross@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
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.