From: Rik van Riel <riel@xxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx> Reviewed-by: Yang Shi <shy828301@xxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Christopher Lameter <cl@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- This patch was applied to v6.1, but was reverted due to a regression report. However it turned out the regression was not due to this patch. I ping'ed Andrew to reapply this patch, Andrew may forget it. This patch helps promote THP, so I rebased it onto the latest mm-unstable. 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); -- 2.41.0
