diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 77a9303..e4ded7a 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1052,6 +1052,49 @@ include 'filename'
+
+ huge_tlb_pages (enum)
+
+ huge_tlb_pages configuration parameter
+
+
+
+ Enables/disables the use of huge TLB pages. Valid values are
+ try (the default), on,
+ and off.
+
+
+
+ At present, this feature is supported only on Linux. The setting
+ is ignored on other systems.
+
+
+
+ The use of huge TLB pages results in smaller page tables and
+ less CPU time spent on memory management. For more details, see
+ hugepages.txt
+ in the Linux kernel documentation.
+
+
+
+ With huge_tlb_pages set to try,
+ the server will try to use huge pages, but fall back to using
+ normal allocation if the first attempt fails.
+
+
+
+ With huge_tlb_pages set to on,
+ the server will try to use huge pages, and treat failure as a
+ FATAL error.
+
+
+
+ With huge_tlb_pages set to off,
+ the server will not try to use huge pages.
+
+
+
+
temp_buffers (integer)
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 707edf1..7d9d0a8 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -113,6 +113,7 @@
#shared_buffers = 32MB # min 128kB
# (change requires restart)
+#huge_tlb_pages = try # try to map memory with MAP_HUGETLB (on, off, try)
#temp_buffers = 8MB # min 800kB
#max_prepared_transactions = 0 # zero disables the feature
# (change requires restart)
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c
index b604407..34937b2 100644
--- a/src/backend/port/sysv_shmem.c
+++ b/src/backend/port/sysv_shmem.c
@@ -27,11 +27,15 @@
#ifdef HAVE_SYS_SHM_H
#include
#endif
+#ifdef MAP_HUGETLB
+#include
+#endif
#include "miscadmin.h"
#include "portability/mem.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
+#include "utils/guc.h"
typedef key_t IpcMemoryKey; /* shared memory key passed to shmget(2) */
@@ -318,6 +322,151 @@ PGSharedMemoryIsInUse(unsigned long id1, unsigned long id2)
}
+#ifdef MAP_HUGETLB
+#define HUGE_PAGE_INFO_DIR "/sys/kernel/mm/hugepages"
+
+/*
+ * long InternalGetFreeHugepagesCount(const char *name)
+ *
+ * Returns the number of free hugepages of a given size, as reported by
+ * /sys/kernel/mm/hugepages//free_hugepages. Will fail (return -1)
+ * if the file could not be opened or 0 if no free pages are available.
+ */
+static long
+InternalGetFreeHugepagesCount(const char *name)
+{
+ int fd;
+ char buff[1024];
+ size_t len;
+ long result;
+ char *ptr;
+
+ len = snprintf(buff, 1024, "%s/%s/free_hugepages", HUGE_PAGE_INFO_DIR, name);
+ if (len == 1024)
+ {
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Filename %s/%s/free_hugepages is too long", HUGE_PAGE_INFO_DIR, name),
+ errcontext("while checking hugepage size")));
+ return -1;
+ }
+
+ fd = open(buff, O_RDONLY);
+ if (fd <= 0)
+ {
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Could not open file %s: %s", buff, strerror(errno)),
+ errcontext("while checking hugepage size")));
+ return -1;
+ }
+
+ len = read(fd, buff, 1024);
+ if (len <= 0)
+ {
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Error reading from file %s: %s", buff, strerror(errno)),
+ errcontext("while checking hugepage size")));
+ close(fd);
+ return -1;
+ }
+ close(fd);
+
+ /*
+ * free_hugepages should contain the number of free hugepages of a
+ * given size. If we somehow read 1024 bytes from it above (which
+ * should never happen), we check 1023 bytes and ignore the rest.
+ */
+ if (len == 1024)
+ len = 1023;
+
+ buff[len] = 0;
+
+ result = strtol(buff, &ptr, 10);
+
+ if (ptr == NULL)
+ {
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Could not convert contents of file %s/%s/free_hugepages to number", HUGE_PAGE_INFO_DIR, name),
+ errcontext("while checking hugepage size")));
+ return -1;
+ }
+
+ return result;
+}
+
+/*
+ * long InternalGetHugepageSize()
+ *
+ * Returns the smallest valid hugepage size by reading the contents of
+ * the /sys/kernel/mm/hugepages directory. Will fail (return -1) if the
+ * directory could not be opened or no valid page sizes are available.
+ */
+static long
+InternalGetHugepageSize()
+{
+ struct dirent *ent;
+ DIR *dir = opendir(HUGE_PAGE_INFO_DIR);
+ long smallest_size = -1, size;
+ bool valid_size_found = false;
+ char *ptr;
+
+ if (dir == NULL)
+ {
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Could not open directory %s: %s", HUGE_PAGE_INFO_DIR, strerror(errno)),
+ errcontext("while checking hugepage size")));
+ return -1;
+ }
+
+ /*
+ * Linux supports multiple hugepage sizes if the hardware
+ * supports it; for each possible size there will be a
+ * directory in /sys/kernel/mm/hugepages consisting of the
+ * string hugepages- and the size of the page, e.g. on x86_64:
+ * hugepages-2048kB
+ */
+ while((ent = readdir(dir)) != NULL)
+ {
+ if (strncmp(ent->d_name, "hugepages-", 10) == 0)
+ {
+ size = strtol(ent->d_name + 10, &ptr, 10);
+ if (ptr == NULL)
+ {
+ continue;
+ }
+
+ if (strcmp(ptr, "kB") == 0)
+ {
+ size *= 1024;
+ }
+
+ if ((smallest_size == -1 || size < smallest_size)) {
+ valid_size_found = true;
+ if(InternalGetFreeHugepagesCount(ent->d_name) > 0)
+ smallest_size = size;
+ }
+ }
+ }
+
+ closedir(dir);
+
+ if (smallest_size == -1)
+ {
+ if(valid_size_found)
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("No free hugepages"),
+ errhint("There were no free huge pages of any size")));
+ else
+ ereport(huge_tlb_pages == HUGE_TLB_TRY ? DEBUG1 : WARNING,
+ (errmsg("Could not find a valid hugepage size"),
+ errhint("This error usually means that either CONFIG_HUGETLB_PAGE "
+ "is not in kernel or that your architecture does not "
+ "support hugepages or you did not configure hugepages")));
+ }
+
+ return smallest_size;
+}
+#endif
+
/*
* PGSharedMemoryCreate
*
@@ -367,7 +516,19 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port)
*/
#ifndef EXEC_BACKEND
{
- long pagesize = sysconf(_SC_PAGE_SIZE);
+ long pagesize = 0;
+ int flags = PG_MMAP_FLAGS;
+
+#ifdef MAP_HUGETLB
+ if (huge_tlb_pages == HUGE_TLB_ON || huge_tlb_pages == HUGE_TLB_TRY)
+ {
+ flags |= MAP_HUGETLB;
+ pagesize = InternalGetHugepageSize();
+ }
+#endif
+
+ if (pagesize <= 0)
+ pagesize = sysconf(_SC_PAGE_SIZE);
/*
* Ensure request size is a multiple of pagesize.
@@ -375,6 +536,10 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port)
* pagesize will, for practical purposes, always be a power of two.
* But just in case it isn't, we do it this way instead of using
* TYPEALIGN().
+ *
+ * The kernel should really remove the need to worry about this,
+ * but see https://bugzilla.kernel.org/show_bug.cgi?id=56881 for
+ * recent situations in which this did not work.
*/
if (pagesize > 0 && size % pagesize != 0)
size += pagesize - (size % pagesize);
@@ -386,8 +551,22 @@ PGSharedMemoryCreate(Size size, bool makePrivate, int port)
* out to be false, we might need to add a run-time test here and do
* this only if the running kernel supports it.
*/
- AnonymousShmem = mmap(NULL, size, PROT_READ | PROT_WRITE, PG_MMAP_FLAGS,
- -1, 0);
+
+ AnonymousShmem = mmap(NULL, size, PROT_READ|PROT_WRITE, flags, -1, 0);
+
+#ifdef MAP_HUGETLB
+ /*
+ * If huge_tlb_pages="try" and the allocation fails, we retry
+ * without the MAP_HUGETLB flag.
+ */
+
+ if (AnonymousShmem == MAP_FAILED && huge_tlb_pages == HUGE_TLB_TRY)
+ {
+ AnonymousShmem = mmap(NULL, size, PROT_READ|PROT_WRITE,
+ PG_MMAP_FLAGS, -1, 0);
+ }
+#endif
+
if (AnonymousShmem == MAP_FAILED)
ereport(FATAL,
(errmsg("could not map anonymous shared memory: %m"),
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 3e981b3..8011e88 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -235,6 +235,24 @@ extern int tcp_keepalives_idle;
extern int tcp_keepalives_interval;
extern int tcp_keepalives_count;
+
+/*
+ * Possible values for huge_tlb_pages; default is HUGE_TLB_TRY
+ */
+typedef enum
+{
+ HUGE_TLB_OFF,
+ HUGE_TLB_ON,
+ HUGE_TLB_TRY
+} HugeTlbType;
+
+
+/*
+ * configure the use of huge TLB pages
+ */
+extern int huge_tlb_pages;
+
+
/*
* Functions exported by guc.c
*/
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index dfc6704..fe09396 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -22,6 +22,9 @@
#include
#include
#include
+#ifdef HAVE_SYS_MMAN_H
+#include
+#endif
#ifdef HAVE_SYSLOG
#include
#endif
@@ -381,6 +384,26 @@ static const struct config_enum_entry synchronous_commit_options[] = {
};
/*
+ * huge_tlb_pages may be on|off|try, where try is the default
+ * on: try to mmap() with MAP_HUGETLB and fail when mmap() fails
+ * off: do not try tp mmap() with MAP_HUGETLB
+ * try: try to mmap() with MAP_HUGETLB and fallback to mmap()
+ * w/o MAP_HUGETLB
+ */
+static const struct config_enum_entry huge_tlb_options[] = {
+ {"off", HUGE_TLB_OFF, false},
+ {"on", HUGE_TLB_ON, false},
+ {"try", HUGE_TLB_TRY, false},
+ {"true", HUGE_TLB_ON, true},
+ {"false", HUGE_TLB_OFF, true},
+ {"yes", HUGE_TLB_ON, true},
+ {"no", HUGE_TLB_OFF, true},
+ {"1", HUGE_TLB_ON, true},
+ {"0", HUGE_TLB_OFF, true},
+ {NULL, 0, false}
+};
+
+/*
* Options for enum values stored in other modules
*/
extern const struct config_enum_entry wal_level_options[];
@@ -440,6 +463,8 @@ int tcp_keepalives_idle;
int tcp_keepalives_interval;
int tcp_keepalives_count;
+int huge_tlb_pages = HUGE_TLB_TRY;
+
/*
* 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
@@ -3377,6 +3402,18 @@ static struct config_enum ConfigureNamesEnum[] =
NULL, NULL, NULL
},
+ {
+ {"huge_tlb_pages",
+ PGC_POSTMASTER,
+ RESOURCES_MEM,
+ gettext_noop("Enable/disable the use of huge TLB pages on Linux"),
+ NULL
+ },
+ &huge_tlb_pages,
+ HUGE_TLB_TRY,
+ huge_tlb_options,
+ NULL, NULL, NULL
+ },
/* End-of-list marker */
{
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 0250e39..051b6cf 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -532,6 +532,9 @@
/* Define to 1 if you have the header file. */
#undef HAVE_SYS_IPC_H
+/* Define to 1 if you have the header file. */
+#undef HAVE_SYS_MMAN_H
+
/* Define to 1 if you have the header file. */
#undef HAVE_SYS_POLL_H
diff --git a/configure.in b/configure.in
index d2bab32..b755202 100644
--- a/configure.in
+++ b/configure.in
@@ -982,7 +982,7 @@ AC_SUBST(OSSP_UUID_LIBS)
##
dnl sys/socket.h is required by AC_FUNC_ACCEPT_ARGTYPES
-AC_CHECK_HEADERS([crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h poll.h pwd.h sys/ioctl.h sys/ipc.h sys/poll.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/socket.h sys/sockio.h sys/tas.h sys/time.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h])
+AC_CHECK_HEADERS([crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h poll.h pwd.h sys/ioctl.h sys/ipc.h sys/mman.h sys/poll.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/socket.h sys/sockio.h sys/tas.h sys/time.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h])
# On BSD, test for net/if.h will fail unless sys/socket.h
# is included first.
diff --git a/configure b/configure
index c20afde..67bc57f 100755
--- a/configure
+++ b/configure
@@ -10524,7 +10524,7 @@ done
-for ac_header in crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h poll.h pwd.h sys/ioctl.h sys/ipc.h sys/poll.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/socket.h sys/sockio.h sys/tas.h sys/time.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h
+for ac_header in crypt.h dld.h fp_class.h getopt.h ieeefp.h ifaddrs.h langinfo.h poll.h pwd.h sys/ioctl.h sys/ipc.h sys/mman.h sys/poll.h sys/pstat.h sys/resource.h sys/select.h sys/sem.h sys/shm.h sys/socket.h sys/sockio.h sys/tas.h sys/time.h sys/un.h termios.h ucred.h utime.h wchar.h wctype.h
do
as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
if { as_var=$as_ac_Header; eval "test \"\${$as_var+set}\" = set"; }; then