* Kalesh Singh firstname.lastname@example.org wrote:
HAVE_MOVE_PUD enables remapping pages at the PUD level if both the source and destination addresses are PUD-aligned.
With HAVE_MOVE_PUD enabled it can be inferred that there is approximately a 13x improvement in performance on x86. (See data below).
------- Test Results ---------
The following results were obtained using a 5.4 kernel, by remapping a PUD-aligned, 1GB sized region to a PUD-aligned destination. The results from 10 iterations of the test are given below:
Total mremap times for 1GB data on x86. All times are in nanoseconds.
180394 15089 235728 14056 238931 25741 187330 13838 241742 14187 177925 14778 182758 14728 160872 14418 205813 15107 245722 13998
205721.5 15594 <-- Mean time in nanoseconds
A 1GB mremap completion time drops from ~205 microseconds to ~15 microseconds on x86. (~13x speed up).
Signed-off-by: Kalesh Singh email@example.com Acked-by: Kirill A. Shutemov firstname.lastname@example.org Cc: Andrew Morton email@example.com Cc: Thomas Gleixner firstname.lastname@example.org Cc: Ingo Molnar email@example.com Cc: Borislav Petkov firstname.lastname@example.org Cc: H. Peter Anvin email@example.com
Assuming it's all correct code:
Acked-by: Ingo Molnar firstname.lastname@example.org