From f54af9f2679d5987b4680e742ac9bd585260e620 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Mon, 7 Jul 2025 21:03:16 -0400 Subject: aio: Combine io_uring memory mappings, if supported By default io_uring creates a shared memory mapping for each io_uring instance, leading to a large number of memory mappings. Unfortunately a large number of memory mappings slows things down, backend exit is particularly affected. To address that, newer kernels (6.5) support using user-provided memory for the memory. By putting the relevant memory into shared memory we don't need any additional mappings. On a system with a new enough kernel and liburing, there is no discernible overhead when doing a pgbench -S -C anymore. Reported-by: MARK CALLAGHAN Reviewed-by: "Burd, Greg" Reviewed-by: Jim Nasby Discussion: https://postgr.es/m/CAFbpF8OA44_UG+RYJcWH9WjF7E3GA6gka3gvH6nsrSnEe9H0NA@mail.gmail.com Backpatch-through: 18 --- configure | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'configure') diff --git a/configure b/configure index 16ef5b58d1a..cfaf3757dd7 100755 --- a/configure +++ b/configure @@ -13309,6 +13309,23 @@ fi fi +if test "$with_liburing" = yes; then + _LIBS="$LIBS" + LIBS="$LIBURING_LIBS $LIBS" + for ac_func in io_uring_queue_init_mem +do : + ac_fn_c_check_func "$LINENO" "io_uring_queue_init_mem" "ac_cv_func_io_uring_queue_init_mem" +if test "x$ac_cv_func_io_uring_queue_init_mem" = xyes; then : + cat >>confdefs.h <<_ACEOF +#define HAVE_IO_URING_QUEUE_INIT_MEM 1 +_ACEOF + +fi +done + + LIBS="$_LIBS" +fi + if test "$with_lz4" = yes ; then { $as_echo "$as_me:${as_lineno-$LINENO}: checking for LZ4_compress_default in -llz4" >&5 $as_echo_n "checking for LZ4_compress_default in -llz4... " >&6; } -- cgit v1.2.3