Hello,
Here is v2 of the mremap start address optimization / fix for exec warning.
v1->v2: 1. Trigger the optimization for mremaps smaller than a PMD. I tested by tracing that it works correctly.
2. Fix issue with bogus return value found by Linus if we broke out of the above loop for the first PMD itself.
Description of patches: These patches optimizes the start addresses in move_page_tables() and tests the changes. It addresses a warning [1] that occurs due to a downward, overlapping move on a mutually-aligned offset within a PMD during exec. By initiating the copy process at the PMD level when such alignment is present, we can prevent this warning and speed up the copying process at the same time. Linus Torvalds suggested this idea.
Please check the individual patches for more details.
thanks,
- Joel
[1] https://lore.kernel.org/all/ZB2GTBD%2FLWTrkOiO@dhcp22.suse.cz/
Joel Fernandes (Google) (4): mm/mremap: Optimize the start addresses in move_page_tables() selftests: mm: Fix failure case when new remap region was not found selftests: mm: Add a test for mutually aligned moves > PMD size selftests: mm: Add a test for remapping to area immediately after existing mapping
mm/mremap.c | 56 +++++++++++++++++++ tools/testing/selftests/mm/mremap_test.c | 69 +++++++++++++++++++++--- 2 files changed, 119 insertions(+), 6 deletions(-)
-- 2.40.1.698.g37aff9b760-goog