Commit 0ba09b17 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Revert "mm: align larger anonymous mappings on THP boundaries" 



This reverts commit f35b5d7d.

It has been reported to cause huge performance regressions on some loads
(will-it-scale.per_process_ops, but also building the kernel with
clang).

The commit did speed up gcc builds by a small amount, so it's not an
unambiguous regression, but until the big regressions are understood,
let's revert it.

Reported-by: default avatarkernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/r/202210181535.7144dd15-yujie.liu@intel.com


Reported-by: default avatarNathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/lkml/Y1DNQaoPWxE%2BrGce@dev-arch.thelio-3990X/


Cc: Huang, Ying <ying.huang@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23393c64

mm/mmap.c

+0 −3
Original line number Diff line number Diff line
@@ -1779,9 +1779,6 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 
		 */

		pgoff = 0;

		get_area = shmem_get_unmapped_area;

	} else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {

		/* Ensures that larger anonymous mappings are THP aligned. */

		get_area = thp_get_unmapped_area;

	}



	addr = get_area(file, addr, len, pgoff, flags);