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 <mdcal...@gmail.com> Reviewed-by: "Burd, Greg" <g...@burd.me> Reviewed-by: Jim Nasby <jna...@upgrade.com> Discussion: https://postgr.es/m/cafbpf8oa44_ug+ryjcwh9wjf7e3ga6gka3gvh6nsrsnee9h...@mail.gmail.com Backpatch-through: 18 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/f54af9f2679d5987b4680e742ac9bd585260e620 Modified Files -------------- configure | 17 +++ configure.ac | 7 + meson.build | 6 + src/backend/storage/aio/method_io_uring.c | 210 +++++++++++++++++++++++++++++- src/include/pg_config.h.in | 3 + src/tools/pgindent/typedefs.list | 1 + 6 files changed, 238 insertions(+), 6 deletions(-)
