>From 0e34f41ac611cf0f4e5bdc3428b71e0f81d33cb0 Mon Sep 17 00:00:00 2001 From: Takashi Menjo Date: Mon, 10 Feb 2020 17:53:16 +0900 Subject: [msync 5/5] Allocate WAL segments to utilize hugepage See also https://nvdimm.wiki.kernel.org/2mib_fs_dax --- src/backend/access/transam/xlog.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 9b3caa63a4..d3ef7bf6e5 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -2904,8 +2904,21 @@ XLogFileInit(XLogSegNo logsegno, bool *use_existent, bool use_lock) memset(zbuffer.data, 0, XLOG_BLCKSZ); pgstat_report_wait_start(WAIT_EVENT_WAL_INIT_WRITE); - save_errno = 0; - if (wal_init_zero) + + /* + * Allocate the file by posix_allocate(3) to utilize hugepage and reduce + * overhead of page fault. Note that posix_fallocate(3) do not set errno + * on error. Instead, it returns an error number directly. + */ + save_errno = posix_fallocate(fd, 0, wal_segment_size); + + if (save_errno) + { + /* + * Do nothing on error. Go to pgstat_report_wait_end(). + */ + } + else if (wal_init_zero) { XLogCtlInsert *Insert = &XLogCtl->Insert; XLogPageHeader NewPage = (XLogPageHeader) zbuffer.data; -- 2.20.1