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/****************************************************************
* *
* Copyright (c) 2012-2023 Fidelity National Information *
* Services, Inc. and/or its subsidiaries. All rights reserved. *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
/*
* This file contains functions related to Linux HugeTLB support.
* Supported Huge Page functionality requires the following prerequisites:
* Linux kernel support of Huge Pages
* x86_64 or i386 architecture
* Availability of Huge Pages through setting value to /proc/sys/vm/nr_hugepages or hugepages=<n> kernel parameter or
* /proc/sys/vm/nr_overcommit_hugepages
* In order to use shmget with Huge Pages, either the process gid should be in /proc/sys/vm/hugetlb_shm_group or the
* process should have CAP_IPC_LOCK
* In order to remap .text/.data/.bss sections, a file system of type hugetlbfs should be mounted
* Appropriate environmental variables should be set (gtm_hugetlb_shm) to enable/disable Huge Pages
*/
#include "mdef.h"
#include "gtm_ipc.h"
#include <sys/shm.h>
#include <errno.h>
#include "gtm_unistd.h"
#include "hugetlbfs_overrides.h"
#undef shmget
#include "send_msg.h"
#include "error.h"
GBLREF bool pin_shared_memory;
GBLREF bool hugetlb_shm_enabled;
error_def(ERR_SHMHUGETLB);
error_def(ERR_SHMLOCK);
error_def(ERR_TEXT);
/* The below array should have an entry corresponding to each type in enum shmget_caller in mdef.h */
static readonly char *errstr[] =
{
"for lock file", /* LOCK_FILE */
"for snapshot file", /* SNAPSHOT_FILE */
"for relink file", /* RELINK */
"for journal pool file", /* JOURNAL_POOL */
"for database file", /* DATABASE_FILE */
"for rc cpt path", /* RC_CPT */
"for gtm_multi_proc", /* GTM_MULTI_PROC_FREEZE */
"for gtm_multi_proc" /* GTM_MULTI_PROC_RECOVER */
};
static char err_string[1024];
int gtm_shmget (key_t key, size_t size, int shmflg, bool lock, enum shmget_caller caller, char *errinfostr)
{
# ifdef HUGETLB_SUPPORTED
int shmid;
struct shmid_ds shmstat;
bool native_shmget = FALSE;
if (hugetlb_shm_enabled)
{
shmid = shmget(key, size, shmflg | SHM_HUGETLB);
if ((-1 == shmid) && ((EPERM == errno) || (ENOMEM == errno)))
{ /* retry without huge pages */
assert(N_SHMGET_CALLERS > caller && NULL != errinfostr);
SNPRINTF(err_string, SIZEOF(err_string), "%s %s", errstr[caller], errinfostr);
send_msg_csa(CSA_ARG(NULL) VARLSTCNT(5) ERR_SHMHUGETLB, 2, RTS_ERROR_TEXT(err_string), errno);
shmid = shmget(key, size, shmflg);
native_shmget = TRUE;
}
} else
{
shmid = shmget(key, size, shmflg);
native_shmget = TRUE;
}
if ((-1 != shmid) && native_shmget && lock && pin_shared_memory)
{ /* shared memory segment successfully allocated, huge pages not in use, and locking requested *
* lock shared memory so it won't be swapped */
if (-1 == shmctl(shmid, SHM_LOCK, &shmstat))
{
send_msg_csa(CSA_ARG(NULL) VARLSTCNT(3) ERR_SHMLOCK, 0, errno);
}
}
return shmid;
# else
return shmget(key, size, shmflg); /* if huge pages are not supported, then neither is locking shm */
# endif
}
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