From 00234f5a0c14e2569ac1e7dab89907196f3ca9e1 Mon Sep 17 00:00:00 2001 From: Justin Pryzby Date: Mon, 23 Jan 2023 18:33:51 -0600 Subject: [PATCH v8] add GUC: huge_pages_active This is useful to show the current state of huge pages when huge_pages=try. The effective status is not otherwise visible without OS level tools like gdb or /proc/N/smaps. https://www.postgresql.org/message-id/flat/TU4PR8401MB1152EBB0D271F827E2E37A01EECC9@TU4PR8401MB1152.NAMPRD84.PROD.OUTLOOK.COM --- doc/src/sgml/config.sgml | 21 ++++++++++++++++++++- src/backend/port/sysv_shmem.c | 10 ++++++++++ src/backend/port/win32_shmem.c | 5 +++++ src/backend/storage/ipc/ipci.c | 7 +++++++ src/backend/utils/misc/guc_tables.c | 20 ++++++++++++++++++++ src/include/storage/pg_shmem.h | 5 +++-- 6 files changed, 65 insertions(+), 3 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 6262cb7bb2f..e69afae71bf 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -1727,7 +1727,8 @@ include_dir 'conf.d' server will try to request huge pages, but fall back to the default if that fails. With on, failure to request huge pages will prevent the server from starting up. With off, - huge pages will not be requested. + huge pages will not be requested. The actual state of huge pages is + indicated by the server variable . @@ -10738,6 +10739,24 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir' + + huge_pages_status (enum) + + huge_pages_status configuration parameter + + + + + Reports the state of huge pages in the current instance: + on, off, or (if displayed with + postgres -C) unknown. + This parameter is useful to determine whether allocation of huge pages + was successful when huge_pages=try. + See for more information. + + + + integer_datetimes (boolean) diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c index eaba244bc9c..0e710237ea1 100644 --- a/src/backend/port/sysv_shmem.c +++ b/src/backend/port/sysv_shmem.c @@ -627,6 +627,10 @@ CreateAnonymousSegment(Size *size) } #endif + /* Report whether huge pages are in use */ + SetConfigOption("huge_pages_status", ptr == MAP_FAILED ? "off" : "on", + PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT); + if (ptr == MAP_FAILED && huge_pages != HUGE_PAGES_ON) { /* @@ -737,8 +741,14 @@ PGSharedMemoryCreate(Size size, sysvsize = sizeof(PGShmemHeader); } else + { sysvsize = size; + /* huge pages are only available with mmap */ + SetConfigOption("huge_pages_status", "off", + PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT); + } + /* * Loop till we find a free IPC key. Trust CreateDataDirLockFile() to * ensure no more than one postmaster per data directory can enter this diff --git a/src/backend/port/win32_shmem.c b/src/backend/port/win32_shmem.c index 62e08074770..87f0b001915 100644 --- a/src/backend/port/win32_shmem.c +++ b/src/backend/port/win32_shmem.c @@ -327,6 +327,11 @@ retry: Sleep(1000); continue; } + + /* Report whether huge pages are in use */ + SetConfigOption("huge_pages_status", (flProtect & SEC_LARGE_PAGES) ? + "on" : "off", PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT); + break; } diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c index 8f1ded7338f..5901a3bd8eb 100644 --- a/src/backend/storage/ipc/ipci.c +++ b/src/backend/storage/ipc/ipci.c @@ -190,6 +190,13 @@ CreateSharedMemoryAndSemaphores(void) */ seghdr = PGSharedMemoryCreate(size, &shim); + /* + * Make sure that huge pages are never reported as "unknown" + * while the server is running. + */ + Assert(strcmp("unknown", + GetConfigOption("huge_pages_status", false, false)) != 0); + InitShmemAccess(seghdr); /* diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c index 977027ec8cb..37a97696dd5 100644 --- a/src/backend/utils/misc/guc_tables.c +++ b/src/backend/utils/misc/guc_tables.c @@ -365,6 +365,13 @@ static const struct config_enum_entry huge_pages_options[] = { {NULL, 0, false} }; +static const struct config_enum_entry huge_pages_status_options[] = { + {"off", HUGE_PAGES_OFF, false}, + {"on", HUGE_PAGES_ON, false}, + {"unknown", HUGE_PAGES_UNKNOWN, false}, + {NULL, 0, false} +}; + static const struct config_enum_entry recovery_prefetch_options[] = { {"off", RECOVERY_PREFETCH_OFF, false}, {"on", RECOVERY_PREFETCH_ON, false}, @@ -551,6 +558,8 @@ int ssl_renegotiation_limit; int huge_pages = HUGE_PAGES_TRY; int huge_page_size; +int huge_pages_status = HUGE_PAGES_UNKNOWN; + /* * These variables are all dummies that don't do anything, except in some * cases provide the value for SHOW to display. The real state is elsewhere @@ -4893,6 +4902,17 @@ struct config_enum ConfigureNamesEnum[] = NULL, NULL, NULL }, + { + {"huge_pages_status", PGC_INTERNAL, PRESET_OPTIONS, + gettext_noop("Indicates the status of huge pages."), + NULL, + GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE + }, + &huge_pages_status, + HUGE_PAGES_UNKNOWN, huge_pages_status_options, + NULL, NULL, NULL + }, + { {"recovery_prefetch", PGC_SIGHUP, WAL_RECOVERY, gettext_noop("Prefetch referenced blocks during recovery."), diff --git a/src/include/storage/pg_shmem.h b/src/include/storage/pg_shmem.h index 4dd05f156d5..bfda42b0b26 100644 --- a/src/include/storage/pg_shmem.h +++ b/src/include/storage/pg_shmem.h @@ -46,12 +46,13 @@ extern PGDLLIMPORT int shared_memory_type; extern PGDLLIMPORT int huge_pages; extern PGDLLIMPORT int huge_page_size; -/* Possible values for huge_pages */ +/* Possible values for huge_pages/huge_pages_status */ typedef enum { HUGE_PAGES_OFF, HUGE_PAGES_ON, - HUGE_PAGES_TRY + HUGE_PAGES_TRY, /* only for huge_pages */ + HUGE_PAGES_UNKNOWN /* only for huge_pages_status */ } HugePagesType; /* Possible values for shared_memory_type */ -- 2.34.1