[LTP] [PATCH v4] mm: rewrite mtest01 with new API
Jan Stancek
jstancek@redhat.com
Wed Mar 13 12:48:04 CET 2019
From: Li Wang <liwang@redhat.com>
Test issue:
mtest01 start many children to alloc chunck of memory and do write
page(with -w option), but occasionally some children were killed by
oom-killer and exit with SIGCHLD signal sending. After the parent
reciving this SIGCHLD signal it will report FAIL as a test result.
It seems not a real kernel bug if something just like that, it's
trying to use 80% of memory and swap. Once it uses most of memory,
system starts swapping, but the test is likely consuming memory at
greater rate than kswapd can provide, which eventually triggers OOM.
---- FAIL LOG ----
mtest01 0 TINFO : Total memory already used on system = 1027392 kbytes
mtest01 0 TINFO : Total memory used needed to reach maximum = 12715520 kbytes
mtest01 0 TINFO : Filling up 80% of ram which is 11688128 kbytes
mtest01 1 TFAIL : mtest01.c:314: child process exited unexpectedly
-------------------
Rewrite changes:
To make mtest01 more easier to understand, I just rewrite it into
LTP new API and make a little changes in children behavior.
* decrease the pressure to 80% of free memory for testing
* drop the signal SIGCHLD action becasue new API help to check_child_status
* make child pause itself after finishing their memory allocating/writing
* parent sends SIGCONT to make children continue and exit
* use TST_PROCESS_STATE_WAIT to wait child changes to 'T' state
* involve ALLOC_THRESHOLD to rework same code in defines
* to make mtest01 support running with -i N > 1
Signed-off-by: Li Wang <liwang@redhat.com>
Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
Li,
I'm posting v4 because I'm proposing also couple other small changes.
Changes in v4:
- fix -b parameter, it was ignored, because maxpercent is always non-zero
Now, if -b is set, then maxpercent is ignored.
- remove casts to unsigned long long, use literal with ULL suffix
- pid_count renamed to children_done, because pid_count vs. pid_cntr was confusing
- original_maxbytes dropped, instead alloc_maxbytes remains unchanged in mem_test()
- do_write_page renamed to do_write_mem, since we write more than single page
- do_write_mem loop now increases offset by page size to make it slightly faster
- bytecount initialized to 0 in child_loop_alloc()
- info messages expanded to show some timestamp (remaining time)
- PASS/FAIL messages for do_write=0 and do_write=1 consolidated to single one
- child creation loop in mem_test() tweaked:
- child_loop_alloc() called directly from loop
- pid_cntr incremented and used as index to pid_list array, 'i' variable not used
- while condition "((pid != 0)" removed, it's always true
- sleep reduced to 100ms
- "while (pid_list[i] > 0)" replaced with for loop, since we know exactly how many
children we spawned. memset in setup dropped.
testcases/kernel/mem/mtest01/mtest01.c | 561 ++++++++++++++-------------------
1 file changed, 235 insertions(+), 326 deletions(-)
rewrite testcases/kernel/mem/mtest01/mtest01.c (92%)
diff --git a/testcases/kernel/mem/mtest01/mtest01.c b/testcases/kernel/mem/mtest01/mtest01.c
dissimilarity index 92%
index ca9073a8e714..df038f50dd2f 100644
--- a/testcases/kernel/mem/mtest01/mtest01.c
+++ b/testcases/kernel/mem/mtest01/mtest01.c
@@ -1,326 +1,235 @@
-/*
- *
- * Copyright (c) International Business Machines Corp., 2001
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
- * the GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-/*
- * FILE : mtest01.c
- * DESCRIPTION : mallocs memory <chunksize> at a time until malloc fails.
- * HISTORY:
- * 04/10/2001 Paul Larson (plars@us.ibm.com)
- * written
- * 11/09/2001 Manoj Iyer (manjo@austin.ibm.com)
- * Modified.
- * - Removed compile warnings.
- * - Added header file #include <unistd.h> definition for getopt()
- * 05/13/2003 Robbie Williamson (robbiew@us.ibm.com)
- * Modified.
- * - Rewrote the test to be able to execute on large memory machines.
- *
- */
-
-#include <sys/types.h>
-#include <sys/sysinfo.h>
-#include <sys/wait.h>
-#include <limits.h>
-#include <signal.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include "test.h"
-
-#define FIVE_HUNDRED_MB (unsigned long long)(500*1024*1024)
-#define ONE_GB (unsigned long long)(1024*1024*1024)
-#define THREE_GB (unsigned long long)(3*ONE_GB)
-
-char *TCID = "mtest01";
-int TST_TOTAL = 1;
-static sig_atomic_t pid_count;
-static sig_atomic_t sigchld_count;
-static pid_t *pid_list;
-
-static void handler(int signo)
-{
- if (signo == SIGCHLD)
- sigchld_count++;
- pid_count++;
-}
-
-static void cleanup(void)
-{
- int i = 0;
-
- while (pid_list[i] > 0) {
- kill(pid_list[i], SIGKILL);
- i++;
- }
-
- free(pid_list);
-}
-
-int main(int argc, char *argv[])
-{
- int c;
- char *mem;
- float percent;
- unsigned int maxpercent = 0, dowrite = 0, verbose = 0, j;
- unsigned long bytecount, alloc_bytes, max_pids;
- unsigned long long original_maxbytes, maxbytes = 0;
- unsigned long long pre_mem = 0, post_mem = 0;
- unsigned long long total_ram, total_free, D, C;
- int chunksize = 1024 * 1024; /* one meg at a time by default */
- struct sysinfo sstats;
- int i, pid_cntr;
- pid_t pid;
- struct sigaction act;
-
- act.sa_handler = handler;
- act.sa_flags = 0;
- sigemptyset(&act.sa_mask);
- sigaction(SIGRTMIN, &act, 0);
- sigaction(SIGCHLD, &act, 0);
-
- while ((c = getopt(argc, argv, "c:b:p:wvh")) != -1) {
- switch (c) {
- case 'c':
- chunksize = atoi(optarg);
- break;
- case 'b':
- if (maxpercent != 0)
- tst_brkm(TBROK, NULL,
- "ERROR: -b option cannot be used with -p "
- "option at the same time");
- maxbytes = atoll(optarg);
- break;
- case 'p':
- if (maxbytes != 0)
- tst_brkm(TBROK, NULL,
- "ERROR: -p option cannot be used with -b "
- "option at the same time");
- maxpercent = atoi(optarg);
- if (maxpercent <= 0)
- tst_brkm(TBROK, NULL,
- "ERROR: -p option requires number greater "
- "than 0");
- if (maxpercent > 99)
- tst_brkm(TBROK, NULL,
- "ERROR: -p option cannot be greater than "
- "99");
- break;
- case 'w':
- dowrite = 1;
- break;
- case 'v':
- verbose = 1;
- break;
- case 'h':
- default:
- printf
- ("usage: %s [-c <bytes>] [-b <bytes>|-p <percent>] [-v]\n",
- argv[0]);
- printf
- ("\t-c <num>\tsize of chunk in bytes to malloc on each pass\n");
- printf
- ("\t-b <bytes>\tmaximum number of bytes to allocate before stopping\n");
- printf
- ("\t-p <bytes>\tpercent of total memory used at which the program stops\n");
- printf
- ("\t-w\t\twrite to the memory after allocating\n");
- printf("\t-v\t\tverbose\n");
- printf("\t-h\t\tdisplay usage\n");
- exit(1);
- }
- }
-
- sysinfo(&sstats);
- total_ram = sstats.totalram + sstats.totalswap;
- total_free = sstats.freeram + sstats.freeswap;
- /* Total Free Pre-Test RAM */
- pre_mem = sstats.mem_unit * total_free;
- max_pids = total_ram * sstats.mem_unit
- / (unsigned long)FIVE_HUNDRED_MB + 10;
-
- if ((pid_list = malloc(max_pids * sizeof(pid_t))) == NULL)
- tst_brkm(TBROK | TERRNO, NULL, "malloc failed.");
- memset(pid_list, 0, max_pids * sizeof(pid_t));
-
- /* Currently used memory */
- C = sstats.mem_unit * (total_ram - total_free);
- tst_resm(TINFO, "Total memory already used on system = %llu kbytes",
- C / 1024);
-
- if (maxpercent) {
- percent = (float)maxpercent / 100.00;
-
- /* Desired memory needed to reach maxpercent */
- D = percent * (sstats.mem_unit * total_ram);
- tst_resm(TINFO,
- "Total memory used needed to reach maximum = %llu kbytes",
- D / 1024);
-
- /* Are we already using more than maxpercent? */
- if (C > D) {
- tst_resm(TFAIL,
- "More memory than the maximum amount you specified "
- " is already being used");
- free(pid_list);
- tst_exit();
- }
-
- /* set maxbytes to the extra amount we want to allocate */
- maxbytes = D - C;
- tst_resm(TINFO, "Filling up %d%% of ram which is %llu kbytes",
- maxpercent, maxbytes / 1024);
- }
- original_maxbytes = maxbytes;
- i = 0;
- pid_cntr = 0;
- pid = fork();
- if (pid < 0)
- tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
- if (pid != 0) {
- pid_cntr++;
- pid_list[i] = pid;
- }
-
-#if defined (_s390_) /* s390's 31bit addressing requires smaller chunks */
- while (pid != 0 && maxbytes > FIVE_HUNDRED_MB) {
- i++;
- if (i >= max_pids)
- tst_brkm(TBROK, cleanup, "max_pids needs to be increased");
- maxbytes -= FIVE_HUNDRED_MB;
- pid = fork();
- if (pid < 0)
- tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
- if (pid != 0) {
- pid_cntr++;
- pid_list[i] = pid;
- }
- }
- if (maxbytes > FIVE_HUNDRED_MB)
- alloc_bytes = FIVE_HUNDRED_MB;
- else
- alloc_bytes = (unsigned long)maxbytes;
-
-#elif __WORDSIZE == 32
- while (pid != 0 && maxbytes > ONE_GB) {
- i++;
- if (i >= max_pids)
- tst_brkm(TBROK, cleanup, "max_pids needs to be increased");
- maxbytes -= ONE_GB;
- pid = fork();
- if (pid < 0)
- tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
- if (pid != 0) {
- pid_cntr++;
- pid_list[i] = pid;
- }
- }
- if (maxbytes > ONE_GB)
- alloc_bytes = ONE_GB;
- else
- alloc_bytes = (unsigned long)maxbytes;
-
-#elif __WORDSIZE == 64
- while (pid != 0 && maxbytes > THREE_GB) {
- i++;
- if (i >= max_pids)
- tst_brkm(TBROK, cleanup, "max_pids needs to be increased");
- maxbytes -= THREE_GB;
- pid = fork();
- if (pid < 0)
- tst_brkm(TBROK | TERRNO, cleanup, "fork failed");
- if (pid != 0) {
- pid_cntr++;
- pid_list[i] = pid;
- }
- }
- alloc_bytes = MIN(THREE_GB, maxbytes);
-#endif
-
- if (pid == 0) {
- bytecount = chunksize;
- while (1) {
- if ((mem = malloc(chunksize)) == NULL) {
- tst_resm(TBROK | TERRNO,
- "stopped at %lu bytes", bytecount);
- free(pid_list);
- tst_exit();
- }
- if (dowrite)
- for (j = 0; j < chunksize; j++)
- *(mem + j) = 'a';
- if (verbose)
- tst_resm(TINFO,
- "allocated %lu bytes chunksize is %d",
- bytecount, chunksize);
- bytecount += chunksize;
- if (alloc_bytes && bytecount >= alloc_bytes)
- break;
- }
- if (dowrite)
- tst_resm(TINFO, "... %lu bytes allocated and used.",
- bytecount);
- else
- tst_resm(TINFO, "... %lu bytes allocated only.",
- bytecount);
- kill(getppid(), SIGRTMIN);
- while (1)
- sleep(1);
- } else {
- sysinfo(&sstats);
-
- if (dowrite) {
- /* Total Free Post-Test RAM */
- post_mem =
- (unsigned long long)sstats.mem_unit *
- sstats.freeram;
- post_mem =
- post_mem +
- (unsigned long long)sstats.mem_unit *
- sstats.freeswap;
-
- while ((((unsigned long long)pre_mem - post_mem) <
- (unsigned long long)original_maxbytes) &&
- pid_count < pid_cntr && !sigchld_count) {
- sleep(1);
- sysinfo(&sstats);
- post_mem =
- (unsigned long long)sstats.mem_unit *
- sstats.freeram;
- post_mem =
- post_mem +
- (unsigned long long)sstats.mem_unit *
- sstats.freeswap;
- }
- }
-
- if (sigchld_count) {
- tst_resm(TFAIL, "child process exited unexpectedly");
- } else if (dowrite) {
- tst_resm(TPASS, "%llu kbytes allocated and used.",
- original_maxbytes / 1024);
- } else {
- tst_resm(TPASS, "%llu kbytes allocated only.",
- original_maxbytes / 1024);
- }
-
- }
- cleanup();
- tst_exit();
-}
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) International Business Machines Corp., 2001
+ * Copyright (c) Linux Test Project., 2019
+ *
+ * DESCRIPTION:
+ *
+ * mtest01 mallocs memory <chunksize> at a time until malloc fails.
+ *
+ * Parent process starts several child processes (each child process is
+ * tasked with allocating some amount of memory), it waits until all child
+ * processes send SIGRTMIN signal and resumes all children by sending the
+ * SIGCONT signal.
+ *
+ * Child process allocates certain amount of memory and fills it with some
+ * data (the '-w' option) so the pages are actually allocated when the desired
+ * amount of memory is allocated then it sends SIGRTMIN signal to the parent
+ * process, it pauses itself by raise SIGSTOP until get parent SIGCONT signal
+ * to continue and exit.
+ */
+
+#include <sys/types.h>
+#include <sys/sysinfo.h>
+#include <sys/wait.h>
+#include <limits.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "tst_test.h"
+
+#define FIVE_HUNDRED_MB (500ULL*1024*1024)
+
+#if defined (_s390_)
+#define ALLOC_THRESHOLD FIVE_HUNDRED_MB
+#elif __WORDSIZE == 32
+#define ALLOC_THRESHOLD (2*FIVE_HUNDRED_MB)
+#elif __WORDSIZE == 64
+#define ALLOC_THRESHOLD (6*FIVE_HUNDRED_MB)
+#endif
+
+#define STOP_THRESHOLD 15 /* seconds remaining before reaching timeout */
+
+static pid_t *pid_list;
+static sig_atomic_t children_done;
+static int max_pids;
+static unsigned long long alloc_maxbytes;
+
+static int chunksize = 1024*1024;
+static int maxpercent = 20;
+static long maxbytes = 0;
+static char *dowrite;
+static char *verbose;
+
+static char *opt_chunksize, *opt_maxbytes, *opt_maxpercent;
+static struct tst_option mtest_options[] = {
+ {"c:", &opt_chunksize, "-c size of chunk in bytes to malloc on each pass"},
+ {"b:", &opt_maxbytes, "-b maximum number of bytes to allocate before stopping"},
+ {"p:", &opt_maxpercent, "-u percent of total memory used at which the program stops"},
+ {"w", &dowrite, "-w write to the memory after allocating"},
+ {"v", &verbose, "-v verbose"},
+ {NULL, NULL, NULL}
+};
+
+static void parse_mtest_options(char *str_chunksize, int *chunksize,
+ char *str_maxbytes, long *maxbytes,
+ char *str_maxpercent, int *maxpercent)
+{
+ if (str_chunksize)
+ if (tst_parse_int(str_chunksize, chunksize, 1, INT_MAX))
+ tst_brk(TBROK, "Invalid chunksize '%s'", str_chunksize);
+
+ if (str_maxbytes) {
+ if (tst_parse_long(str_maxbytes, maxbytes, 1, LONG_MAX)) {
+ tst_brk(TBROK, "Invalid maxbytes '%s'", str_maxbytes);
+ } else if (str_maxpercent) {
+ tst_brk(TBROK, "ERROR: -b option cannot be used with -p "
+ "option at the same time");
+ }
+ alloc_maxbytes = (unsigned long long)maxbytes;
+ }
+
+ if (str_maxpercent) {
+ if (tst_parse_int(str_maxpercent, maxpercent, 1, 99)) {
+ tst_brk(TBROK, "Invalid maxpercent '%s'", str_maxpercent);
+ } else if (str_maxbytes) {
+ tst_brk(TBROK, "ERROR: -p option cannot be used with -b "
+ "option at the same time");
+ }
+ }
+}
+
+static void handler(int sig LTP_ATTRIBUTE_UNUSED)
+{
+ children_done++;
+}
+
+static void do_write_mem(char *mem, int chunksize)
+{
+ int i, pagesz = getpagesize();
+
+ for (i = 0; i < chunksize; i += pagesz)
+ *(mem + i) = 'a';
+}
+
+static void setup(void)
+{
+ struct sysinfo sstats;
+ unsigned long long total_free;
+
+ struct sigaction act;
+ act.sa_handler = handler;
+ act.sa_flags = 0;
+ sigemptyset(&act.sa_mask);
+ sigaction(SIGRTMIN, &act, 0);
+
+ parse_mtest_options(opt_chunksize, &chunksize,
+ opt_maxbytes, &maxbytes,
+ opt_maxpercent, &maxpercent);
+ sysinfo(&sstats);
+ total_free = sstats.freeram;
+
+ max_pids = total_free * sstats.mem_unit
+ / (unsigned long)ALLOC_THRESHOLD + 10;
+ pid_list = SAFE_MALLOC(max_pids * sizeof(pid_t));
+
+ if (!alloc_maxbytes) {
+ /* set alloc_maxbytes to the extra amount we want to allocate */
+ alloc_maxbytes = ((float)maxpercent / 100.00)
+ * (sstats.mem_unit * total_free);
+ tst_res(TINFO, "Filling up %d%% of free ram which is %llu kbytes",
+ maxpercent, alloc_maxbytes / 1024);
+ }
+}
+
+static void cleanup(void)
+{
+ if(pid_list)
+ free(pid_list);
+}
+
+static void child_loop_alloc(unsigned long long alloc_bytes)
+{
+ unsigned long bytecount = 0;
+ char *mem;
+
+ tst_res(TINFO, "... child %d starting", getpid());
+
+ while (1) {
+ mem = SAFE_MALLOC(chunksize);
+ if (dowrite)
+ do_write_mem(mem, chunksize);
+
+ if (verbose)
+ tst_res(TINFO,
+ "child %d allocated %lu bytes chunksize is %d",
+ getpid(), bytecount, chunksize);
+ bytecount += chunksize;
+ if (bytecount >= alloc_bytes)
+ break;
+ }
+ if (dowrite)
+ tst_res(TINFO, "... [t=%d] %lu bytes allocated and used in child %d",
+ tst_timeout_remaining(), bytecount, getpid());
+ else
+ tst_res(TINFO, "... [t=%d] %lu bytes allocated only in child %d",
+ tst_timeout_remaining(), bytecount, getpid());
+
+ kill(getppid(), SIGRTMIN);
+ raise(SIGSTOP);
+ exit(0);
+}
+
+static void mem_test(void)
+{
+ pid_t pid;
+ int i = 0, pid_cntr = 0;
+ unsigned long long alloc_bytes = alloc_maxbytes;
+ const char *write_msg = "";
+
+ if (dowrite)
+ write_msg = "(and written to) ";
+
+ /* to make mtest01 support -i N */
+ children_done = 0;
+
+ do {
+ pid = SAFE_FORK();
+ if (pid == 0) {
+ alloc_bytes = MIN(ALLOC_THRESHOLD, alloc_bytes);
+ child_loop_alloc(alloc_bytes);
+ }
+
+ pid_list[pid_cntr++] = pid;
+
+ if (alloc_bytes <= ALLOC_THRESHOLD)
+ break;
+
+ alloc_bytes -= ALLOC_THRESHOLD;
+ } while (pid_cntr < max_pids);
+
+ /* wait in the loop for all children finish allocating */
+ while (children_done < pid_cntr) {
+ if (tst_timeout_remaining() < STOP_THRESHOLD) {
+ tst_res(TWARN,
+ "the remaininig time is not enough for testing");
+
+ break;
+ }
+
+ usleep(100000);
+ }
+
+ if (children_done < pid_cntr) {
+ tst_res(TFAIL, "kbytes allocated %sless than expected %llu",
+ write_msg, alloc_maxbytes / 1024);
+ } else {
+ tst_res(TPASS, "%llu kbytes allocated %s",
+ alloc_maxbytes / 1024, write_msg);
+ }
+
+ for (i = 0; i < pid_cntr; i++) {
+ TST_PROCESS_STATE_WAIT(pid_list[i], 'T');
+ kill(pid_list[i], SIGCONT);
+ }
+}
+
+static struct tst_test test = {
+ .forks_child = 1,
+ .options = mtest_options,
+ .setup = setup,
+ .cleanup = cleanup,
+ .test_all = mem_test,
+};
--
1.8.3.1
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