linux/include
David Hildenbrand 3dfde97800 mm: add get_and_clear_ptes() and clear_ptes()
Patch series "Optimizations for khugepaged", v4.

If the underlying folio mapped by the ptes is large, we can process those
ptes in a batch using folio_pte_batch().

For arm64 specifically, this results in a 16x reduction in the number of
ptep_get() calls, since on a contig block, ptep_get() on arm64 will
iterate through all 16 entries to collect a/d bits.  Next, ptep_clear()
will cause a TLBI for every contig block in the range via
contpte_try_unfold().  Instead, use clear_ptes() to only do the TLBI at
the first and last contig block of the range.

For split folios, there will be no pte batching; the batch size returned
by folio_pte_batch() will be 1.  For pagetable split folios, the ptes will
still point to the same large folio; for arm64, this results in the
optimization described above, and for other arches, a minor improvement is
expected due to a reduction in the number of function calls and batching
atomic operations.


This patch (of 3):

Let's add variants to be used where "full" does not apply -- which will
be the majority of cases in the future. "full" really only applies if
we are about to tear down a full MM.

Use get_and_clear_ptes() in existing code, clear_ptes() users will
be added next.

Link: https://lkml.kernel.org/r/20250724052301.23844-2-dev.jain@arm.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Barry Song <baohua@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-08-02 12:06:10 -07:00
..
acpi
asm-generic mm: drop hugetlb_free_pgd_range() 2025-07-24 19:12:32 -07:00
clocksource
crypto Crypto library fix for v6.16-rc4 2025-06-27 17:32:30 -07:00
cxl
drm drm/sched: Increment job count before swapping tail spsc queue 2025-07-01 16:14:47 -07:00
dt-bindings USB/Thunderbolt changes for 6.16-rc1 2025-06-06 12:45:35 -07:00
hyperv hyperv-next for v6.16 2025-06-03 08:39:20 -07:00
keys
kunit I've recently moved computers (among other things) so I'm sending this from a 2025-05-30 09:15:40 -07:00
kvm KVM: arm64: Resolve vLPI by host IRQ in vgic_v4_unset_forwarding() 2025-05-30 09:11:29 +01:00
linux mm: add get_and_clear_ptes() and clear_ptes() 2025-08-02 12:06:10 -07:00
math-emu
media
memory
misc
net Bluetooth: hci_core: Fix use-after-free in vhci_flush() 2025-06-23 10:59:29 -04:00
pcmcia
ras
rdma
rv
scsi SCSI misc on 20250529 2025-05-29 22:17:52 -07:00
soc - The 3 patch series "hung_task: extend blocking task stacktrace dump to 2025-05-31 19:12:53 -07:00
sound USB/Thunderbolt changes for 6.16-rc1 2025-06-06 12:45:35 -07:00
target
trace mm/page_alloc: remove trace_mm_alloc_contig_migrate_range_info() 2025-07-26 15:08:22 -07:00
uapi block-6.16-20250626 2025-06-27 09:02:33 -07:00
ufs
vdso
video fbdev: atyfb: Remove unused PCI vendor ID 2025-05-31 10:24:01 +02:00
xen
Kbuild