99b86c9b07
[ Upstream commit c3235e2dd6956448a562d6b1112205eeebc8ab43 ] The shadow gmap tracks memory of nested guests (guest-3). In certain scenarios, the shadow gmap needs to be rebuilt, which is a costly operation since it involves a SIE exit into guest-1 for every entry in the respective shadow level. Add kvm stat counters when new shadow structures are created at various levels. Also add a counter gmap_shadow_create when a completely fresh shadow gmap is created as well as a counter gmap_shadow_reuse when an existing gmap is being reused. Note that when several levels are shadowed at once, counters on all affected levels will be increased. Also note that not all page table levels need to be present and a ASCE can directly point to e.g. a segment table. In this case, a new segment table will always be equivalent to a new shadow gmap and hence will be counted as gmap_shadow_create and not as gmap_shadow_segment. Signed-off-by: Nico Boehr <nrb@linux.ibm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Link: https://lore.kernel.org/r/20231009093304.2555344-2-nrb@linux.ibm.com Message-Id: <20231009093304.2555344-2-nrb@linux.ibm.com> Stable-dep-of: fe752331d4b3 ("KVM: s390: vsie: fix race during shadow creation") Signed-off-by: Sasha Levin <sashal@kernel.org>
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.