From c45a6aa1453c4b1bde59fb96ef93e2d94ac72a06 Mon Sep 17 00:00:00 2001 From: Nathan Bossart Date: Fri, 23 Feb 2024 14:43:50 -0600 Subject: [PATCH v3 2/2] Convert archiver's force_dir_scan variable to an atomic variable. Commit XXXXXXXXXX introduced new atomic read/write functions with full barrier semantics, which are intended to ease converting non- performance-critical code to use atomic variables. This commit demonstrates one such conversion. Reviewed-by: Yong Li Discussion: https://postgr.es/m/20231110205128.GB1315705%40nathanxps13 --- src/backend/postmaster/pgarch.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c index 9c18e4b3ef..a8ec76ab81 100644 --- a/src/backend/postmaster/pgarch.c +++ b/src/backend/postmaster/pgarch.c @@ -45,7 +45,6 @@ #include "storage/proc.h" #include "storage/procsignal.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "utils/guc.h" #include "utils/memutils.h" #include "utils/ps_status.h" @@ -83,11 +82,9 @@ typedef struct PgArchData int pgprocno; /* pgprocno of archiver process */ /* - * Forces a directory scan in pgarch_readyXlog(). Protected by arch_lck. + * Forces a directory scan in pgarch_readyXlog(). */ - bool force_dir_scan; - - slock_t arch_lck; + pg_atomic_uint32 force_dir_scan; } PgArchData; char *XLogArchiveLibrary = ""; @@ -174,7 +171,7 @@ PgArchShmemInit(void) /* First time through, so initialize */ MemSet(PgArch, 0, PgArchShmemSize()); PgArch->pgprocno = INVALID_PGPROCNO; - SpinLockInit(&PgArch->arch_lck); + pg_atomic_init_u32(&PgArch->force_dir_scan, false); } } @@ -545,18 +542,12 @@ pgarch_readyXlog(char *xlog) char XLogArchiveStatusDir[MAXPGPATH]; DIR *rldir; struct dirent *rlde; - bool force_dir_scan; /* * If a directory scan was requested, clear the stored file names and * proceed. */ - SpinLockAcquire(&PgArch->arch_lck); - force_dir_scan = PgArch->force_dir_scan; - PgArch->force_dir_scan = false; - SpinLockRelease(&PgArch->arch_lck); - - if (force_dir_scan) + if (pg_atomic_exchange_u32(&PgArch->force_dir_scan, false)) arch_files->arch_files_size = 0; /* @@ -707,9 +698,7 @@ ready_file_comparator(Datum a, Datum b, void *arg) void PgArchForceDirScan(void) { - SpinLockAcquire(&PgArch->arch_lck); - PgArch->force_dir_scan = true; - SpinLockRelease(&PgArch->arch_lck); + pg_atomic_write_membarrier_u32(&PgArch->force_dir_scan, true); } /* -- 2.25.1