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Message-ID: <20231214223423.1133074-1-yang@os.amperecomputing.com>
Date: Thu, 14 Dec 2023 14:34:23 -0800
From: Yang Shi <yang@...amperecomputing.com>
To: riel@...riel.com,
shy828301@...il.com,
willy@...radead.org,
cl@...ux.com,
akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Subject: [RESEND PATCH] mm: align larger anonymous mappings on THP boundaries
From: Rik van Riel <riel@...riel.com>
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 <riel@...riel.com>
Reviewed-by: Yang Shi <shy828301@...il.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Christopher Lameter <cl@...ux.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
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
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