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[Xen-devel] [For Xen-4.10 PATCH 0/3] Reduce unnecessary icache maintenance operations


This series was previously posted as an RFC[0]. An issue was discovered
in the RFC related to delaying icache invalidations when the domain is
active. Accordingly, Patch 3 has been modified to avoid per-page
icache invalidations only during domain creation.

Changes from RFC:

* Fixed coding style issue in Patch 1
* Added reviewed-by tags
* Re-worked Patch 3 to defer icache optimisation only during domain creation

Patch 1 adds a parameter to flush_page_to_ram() to prevent performing
icache maintenance per page. Current calls to flush_page_to_ram() loop
over pages and performing a full icache flush for each page is

Patch 2 hoists icache maintenance from flush_page_to_ram() to

Patch 3 introduces a new MEMF_ flag to indicate to alloc_heap_pages()
that icache maintenance will be performed by the caller. The icache
maintenance operations are performed in populate_physmap() during
domain creation. As I couldn't find icache maintenance operations for
x86, an empty helper is introduced.


[0] https://www.mail-archive.com/xen-devel@xxxxxxxxxxxxx/msg102934.html

Punit Agrawal (3):
  Allow control of icache invalidations when calling flush_page_to_ram()
  arm: p2m: Prevent redundant icache flushes
  Avoid excess icache flushes in populate_physmap() before domain has
    been created

 xen/arch/arm/mm.c              |  5 +++--
 xen/arch/arm/p2m.c             |  4 +++-
 xen/common/memory.c            | 31 ++++++++++++++++++++++---------
 xen/common/page_alloc.c        |  2 +-
 xen/include/asm-arm/page.h     |  2 +-
 xen/include/asm-x86/flushtlb.h |  2 +-
 xen/include/asm-x86/page.h     |  4 ++++
 xen/include/xen/mm.h           |  2 ++
 8 files changed, 37 insertions(+), 15 deletions(-)


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