From a1023326b5895f2820424f96612c2fd945d5f424 Mon Sep 17 00:00:00 2001 From: "Chao Li (Evan)" Date: Mon, 14 Sep 2026 15:16:20 +0800 Subject: [PATCH v1] Avoid extra shared-memory page in CalculateShmemSize() CalculateShmemSize() rounds the requested shared-memory size up to a multiple of 8192 bytes. When the size is already aligned, however, the calculation adds another 8192 bytes unnecessarily. Only add the padding when the size is not already a multiple of 8192. Author: Chao Li --- src/backend/storage/ipc/ipci.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c index e149a738c8d..3a221b88f37 100644 --- a/src/backend/storage/ipc/ipci.c +++ b/src/backend/storage/ipc/ipci.c @@ -73,8 +73,9 @@ CalculateShmemSize(void) /* include additional requested shmem from preload libraries */ size = add_size(size, total_addin_request); - /* might as well round it off to a multiple of a typical page size */ - size = add_size(size, 8192 - (size % 8192)); + if (size % 8192 != 0) + /* might as well round it off to a multiple of a typical page size */ + size = add_size(size, 8192 - (size % 8192)); return size; } -- 2.50.1 (Apple Git-155)