linux/drivers/virt
Matthew Wilcox (Oracle) f9bff0e318 minmax: add in_range() macro
Patch series "New page table range API", v6.

This patchset changes the API used by the MM to set up page table entries.
The four APIs are:

    set_ptes(mm, addr, ptep, pte, nr)
    update_mmu_cache_range(vma, addr, ptep, nr)
    flush_dcache_folio(folio) 
    flush_icache_pages(vma, page, nr)

flush_dcache_folio() isn't technically new, but no architecture
implemented it, so I've done that for them.  The old APIs remain around
but are mostly implemented by calling the new interfaces.

The new APIs are based around setting up N page table entries at once. 
The N entries belong to the same PMD, the same folio and the same VMA, so
ptep++ is a legitimate operation, and locking is taken care of for you. 
Some architectures can do a better job of it than just a loop, but I have
hesitated to make too deep a change to architectures I don't understand
well.

One thing I have changed in every architecture is that PG_arch_1 is now a
per-folio bit instead of a per-page bit when used for dcache clean/dirty
tracking.  This was something that would have to happen eventually, and it
makes sense to do it now rather than iterate over every page involved in a
cache flush and figure out if it needs to happen.

The point of all this is better performance, and Fengwei Yin has measured
improvement on x86.  I suspect you'll see improvement on your architecture
too.  Try the new will-it-scale test mentioned here:
https://lore.kernel.org/linux-mm/20230206140639.538867-5-fengwei.yin@intel.com/
You'll need to run it on an XFS filesystem and have
CONFIG_TRANSPARENT_HUGEPAGE set.

This patchset is the basis for much of the anonymous large folio work
being done by Ryan, so it's received quite a lot of testing over the last
few months.


This patch (of 38):

Determine if a value lies within a range more efficiently (subtraction +
comparison vs two comparisons and an AND).  It also has useful (under some
circumstances) behaviour if the range exceeds the maximum value of the
type.  Convert all the conflicting definitions of in_range() within the
kernel; some can use the generic definition while others need their own
definition.

Link: https://lkml.kernel.org/r/20230802151406.3735276-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230802151406.3735276-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-08-24 16:20:18 -07:00
..
acrn minmax: add in_range() macro 2023-08-24 16:20:18 -07:00
coco virt: sevguest: Add CONFIG_CRYPTO dependency 2023-06-09 15:53:07 +02:00
nitro_enclaves kunit: fix Kconfig for build-in tests USB4 and Nitro Enclaves 2022-09-01 13:00:48 -06:00
vboxguest virt: vbox: Remove unproper information 2022-09-09 10:19:18 +02:00
fsl_hypervisor.c virt: fsl: Use of_property_present() for testing DT property presence 2023-04-21 09:20:56 -05:00
Kconfig virt: Add TDX guest driver 2022-11-17 11:04:23 -08:00
Makefile virt: Add TDX guest driver 2022-11-17 11:04:23 -08:00
vmgenid.c virt: vmgenid: recognize new CID added by Hyper-V 2022-03-25 08:49:40 -06:00