From f35b5d7d676e59e401690b678cd3cfec5e785c23 Mon Sep 17 00:00:00 2001 From: Rik van Riel Date: Tue, 9 Aug 2022 14:24:57 -0400 Subject: [PATCH] mm: align larger anonymous mappings on THP boundaries Align larger anonymous memory mappings on THP boundaries by going through thp_get_unmapped_area if THPs are enabled for the current process. With this patch, larger anonymous mappings are now THP aligned. When a malloc library allocates a 2MB or larger arena, that arena can now be mapped with THPs right from the start, which can result in better TLB hit rates and execution time. Link: https://lkml.kernel.org/r/20220809142457.4751229f@imladris.surriel.com Signed-off-by: Rik van Riel Reviewed-by: Yang Shi Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/mmap.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 9d780f415be3..dd25a2aa94f7 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2232,6 +2232,9 @@ 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);