Linux 虚拟内存限制
Linux virtual memory limit
我正在尝试为进程 (Tsw) 分配内存。不幸的是，我不能分配超过 ~ 1 Gb 的虚拟内存（在 for 循环中分配 2MB 块）。执行期间无限制更改命令。
这是 cat /proc/$(pidof Tsw)/limits 命令的输出。
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 13633 13633 processes
Max open files 1024 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 13633 13633 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
这里是top命令的部分输出（注意/usr/bin/Tsw，从顶部数第三个过程）：
Mem: 1082976K used, 990736K free, 0K shrd, 128K buff, 28136K cached
CPU: 0% usr 4% sys 0% nic 95% idle 0% io 0% irq 0% sirq
Load average: 1.07 0.36 0.13 1/242 2007
PID PPID USER STAT VSZ %VSZ %CPU COMMAND
1730 1690 root S 179m 9% 2% /usr/bin/btsvc_main_9300
585 1 root S 45784 2% 2% /usr/bin/brsCore --test-software
1691 1 root S 997m 49% 0% /usr/bin/Tsw
1941 1 root S 121m 6% 0% /usr/sbin/unifi_helper_tsw --wifi-ptest --wifi-char-device /dev/unifiudi0 --wifi-ptest-firmware ptest/firmware/ptest_unifi_93xx_a07_ptdl.xbv --wifi-ptest-profile ptest/profile/unitest_profile_CSRC9xxx_Cust_BGA.txt --log-level-text CsrWifiPtestApp..A
1687 1683 root S 119m 6% 0% /usr/sbin/unifi_helper_tsw --wifi-char-device /dev/unifi0 --wifi-on --wifi-restart-on-error --wifi-exit-on-error --wifi-exit-on-unplug --wifi-address 00:1C:C1:A2:5D:FF --wifi-mib --wifi-add-interface ff:ff:ff:ff:ff:ff
1693 1 root S 70452 3% 0% /usr/bin/avTSWCdspAudio.exe /usr/lib/audiomanager/routing/libavPluginRoutingDirana.so
1219 1 root S 66740 3% 0% /usr/bin/TSWNav_GNSS
1215 1 root S 63460 3% 0% /usr/bin/dlt-system -c /etc/dlt-system.conf
1039 1 root S 50464 2% 0% /usr/bin/avDiranaBoot.exe -t DIRANA3 -p /run/audio/dirana_boot.pipe -r 0 -d 0
1216 1 root S 48400 2% 0% /usr/bin/RadioAppTSW
1493 1 root S 47184 2% 0% /usr/bin/ssw_pers_pccl_hwi_svc
1494 1 root S 47180 2% 0% /usr/bin/ssw_pers_pccl_early_svc
1690 1 root S 35672 2% 0% /usr/bin/btsvc_main_9300
1692 1 root S 30516 1% 0% /usr/bin/tsw-apple-authic-info
1 0 root S 30060 1% 0% {systemd} /sbin/init
1225 1 root S 28224 1% 0% /usr/bin/TSWNav_Gyro
1224 1 root S 28220 1% 0% /usr/bin/TSWNav_Accel
1212 1 root S 26968 1% 0% /usr/bin/tsw-ipc-sample
793 1 root S 19532 1% 0% /usr/bin/ssw_pers_nba_svc
622 1 root S 6656 0% 0% /usr/lib/systemd/systemd-journald
1232 1 root S 4440 0% 0% /usr/sbin/sshd -D
746 1 root S 3448 0% 0% /usr/lib/systemd/systemd-udevd
2003 1691 root S 2960 0% 0% sh -c mount -o remount, rw / && cd usr/bin && top -b -n 1 > statistics_after.txt
2007 2003 root R 2960 0% 0% top -b -n 1
1682 30 root S 2960 0% 0% {unififw} /bin/sh /usr/sbin/unififw 0 2
1683 1682 root S 2960 0% 0% {unififw} /bin/sh /usr/sbin/unififw 0 2
1209 1 root S 2708 0% 0% /usr/bin/dlt-daemon
1694 1 root S 2660 0% 0% /usr/sbin/conn_wifi_tsw
1297 1 messageb S 2552 0% 0% /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
1685 1682 root S 1820 0% 0% logger -t unififw -p daemon.notice
1625 1 root S 1816 0% 0% ldattach -8e1s 2000000 19 /dev/ttymxc1
1161 2 root SW 0 0% 0% [irq/65-2010000.]
8 2 root SW 0 0% 0% [rcu_preempt]
1629 2 root SW 0 0% 0% [hydra-sdio-io]
482 2 root SW 0 0% 0% [kworker/u8:2]
6 2 root SW 0 0% 0% [kworker/u8:0]
560 2 root SW 0 0% 0% [ubi_bgt0d]
1577 2 root SW 0 0% 0% [file_server_thr]
699 2 root SW 0 0% 0% [rtp_parser]
754 2 root SW 0 0% 0% [rtp_isr_data_th]
1464 2 root SW 0 0% 0% [mmcqd/1]
3 2 root SW 0 0% 0% [ksoftirqd/0]
701 2 root SW 0 0% 0% [rtp_write_threa]
755 2 root SW 0 0% 0% [spi_send_thread]
756 2 root SW 0 0% 0% [rtp_parser_thre]
1163 2 root SW 0 0% 0% [spi2]
1387 2 root SW 0 0% 0% [irq/54-mmc0]
1630 2 root SW 0 0% 0% [hydra/complete]
30 2 root SW 0 0% 0% [kworker/u8:1]
1210 2 root SW 0 0% 0% [kworker/0:2]
2 0 root SW 0 0% 0% [kthreadd]
4 2 root SW 0 0% 0% [kworker/0:0]
5 2 root SW< 0 0% 0% [kworker/0:0H]
7 2 root SW 0 0% 0% [migration/0]
9 2 root SW 0 0% 0% [rcu_bh]
10 2 root SW 0 0% 0% [rcu_sched]
11 2 root SW 0 0% 0% [watchdog/0]
12 2 root SW 0 0% 0% [watchdog/1]
13 2 root SW 0 0% 0% [migration/1]
14 2 root SW 0 0% 0% [ksoftirqd/1]
15 2 root SW 0 0% 0% [kworker/1:0]
16 2 root SW< 0 0% 0% [kworker/1:0H]
17 2 root SW 0 0% 0% [watchdog/2]
18 2 root SW 0 0% 0% [migration/2]
19 2 root SW 0 0% 0% [ksoftirqd/2]
20 2 root SW 0 0% 0% [kworker/2:0]
21 2 root SW< 0 0% 0% [kworker/2:0H]
22 2 root SW 0 0% 0% [watchdog/3]
23 2 root SW 0 0% 0% [migration/3]
24 2 root SW 0 0% 0% [ksoftirqd/3]
25 2 root SW 0 0% 0% [kworker/3:0]
26 2 root SW< 0 0% 0% [kworker/3:0H]
27 2 root SW< 0 0% 0% [khelper]
28 2 root SW 0 0% 0% [kdevtmpfs]
29 2 root SW< 0 0% 0% [netns]
37 2 root SW 0 0% 0% [kworker/0:1]
38 2 root SW 0 0% 0% [kworker/1:1]
39 2 root SW 0 0% 0% [kworker/2:1]
40 2 root SW 0 0% 0% [kworker/3:1]
241 2 root SW< 0 0% 0% [writeback]
243 2 root SW< 0 0% 0% [bioset]
245 2 root SW< 0 0% 0% [kblockd]
279 2 root SW 0 0% 0% [khubd]
307 2 root SW 0 0% 0% [ipu1_task]
308 2 root SW 0 0% 0% [ipu1_task]
309 2 root SW 0 0% 0% [ipu2_task]
310 2 root SW 0 0% 0% [ipu2_task]
343 2 root SW 0 0% 0% [kswapd0]
402 2 root SW 0 0% 0% [fsnotify_mark]
406 2 root SW< 0 0% 0% [crypto]
416 2 root SW< 0 0% 0% [shm_workqueue]
429 2 root SW 0 0% 0% [kworker/2:2]
474 2 root SW< 0 0% 0% [usbdiag_queue]
481 2 root SW< 0 0% 0% [ci_otg]
511 2 root SW< 0 0% 0% [deferwq]
544 2 root SW 0 0% 0% [gpmi_statistics]
700 2 root SW< 0 0% 0% [rtp_admin]
753 2 root SW 0 0% 0% [spi0]
795 2 root SW 0 0% 0% [kworker/1:2]
1040 2 root SW 0 0% 0% [kworker/3:2]
1152 2 root SW 0 0% 0% [spi1]
1177 2 root SW 0 0% 0% [spi4]
1269 2 root SW< 0 0% 0% [vpu_wq]
1406 2 root SW 0 0% 0% [ubifs_bgt0_60]
1409 2 root SW 0 0% 0% [irq/56-mmc1]
1413 2 root SW 0 0% 0% [kworker/u8:3]
1465 2 root SW 0 0% 0% [mmcqd/1boot0]
1466 2 root SW 0 0% 0% [mmcqd/1boot1]
1467 2 root SW 0 0% 0% [mmcqd/1rpmb]
1480 2 root SW< 0 0% 0% [kworker/0:1H]
1482 2 root SW< 0 0% 0% [kworker/2:1H]
1486 2 root SW< 0 0% 0% [kworker/1:1H]
1533 2 root SW 0 0% 0% [jbd2/mmcblk1p3-]
1534 2 root SW< 0 0% 0% [ext4-dio-unwrit]
1536 2 root SW 0 0% 0% [jbd2/mmcblk1p2-]
1537 2 root SW< 0 0% 0% [ext4-dio-unwrit]
1578 2 root SW< 0 0% 0% [coredump_wq]
1631 2 root SW 0 0% 0% [service_mgr_thr]
1679 2 root SW< 0 0% 0% [unifi_workq]
1717 2 root SW 0 0% 0% [ubifs_bgt0_50]
1758 2 root SW 0 0% 0% [ubifs_bgt0_17]
1759 2 root SW 0 0% 0% [UNIFI_BH]
1766 2 root SW 0 0% 0% [hydra/complete]
1936 2 root SW 0 0% 0% [reader]
1937 2 root SW 0 0% 0% [writer]
我是这样分配的：
// RAM_SIZE = 1.5 Gb
// RAM_BLOCK_TEST = 2 Mb
#define RAM_SIZE (1024U * 1024U * 1536U)
#define RAM_BLOCK_TEST (1024U * 1024U * 2U)
uint32_t uiMemBlockCount = 0;
// uiLoopNr = 768
uint32_t uiLoopNr = (uint32_t)RAM_SIZE/(uint32_t)RAM_BLOCK_TEST;
uint8_t* pcMemArray[uiLoopNr];
for(uiMemBlockCount = 0; uiMemBlockCount < uiLoopNr; uiMemBlockCount++)
{
pcMemArray[uiMemBlockCount] = (uint8_t*)calloc(RAM_BLOCK_TEST, sizeof(uint8_t));
if (NULL == pcMemArray[uiMemBlockCount])
{
printf("Allocated %u block(s) of memory with %d size", uiMemBlockCount, RAM_BLOCK_TEST);
break;
}
}
也许 Linux OS 中还有其他限制不允许我这样做？
谢谢！
我找到问题了。
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
vmalloc : 0xc0800000 - 0xff000000 (1000 MB)
lowmem : 0x40000000 - 0xc0000000 (2048 MB)
modules : 0x3f000000 - 0x40000000 ( 16 MB)
.text : 0x40008000 - 0x40411ef4 (4136 kB)
.init : 0x40412000 - 0x4043ce80 ( 172 kB)
.data : 0x4043e000 - 0x404607c0 ( 138 kB)
.bss : 0x404607c0 - 0x40498208 ( 223 kB)
lowmem 从 0x40000000 开始。
所以我每个进程的虚拟内存不能超过 1 Gb。
这可以在内核配置中使用 CONFIG_PAGE_OFFSET 进行更改。
我正在尝试为进程 (Tsw) 分配内存。不幸的是，我不能分配超过 ~ 1 Gb 的虚拟内存（在 for 循环中分配 2MB 块）。执行期间无限制更改命令。
这是 cat /proc/$(pidof Tsw)/limits 命令的输出。
Limit Soft Limit Hard Limit Units
Max cpu time unlimited unlimited seconds
Max file size unlimited unlimited bytes
Max data size unlimited unlimited bytes
Max stack size 8388608 unlimited bytes
Max core file size 0 unlimited bytes
Max resident set unlimited unlimited bytes
Max processes 13633 13633 processes
Max open files 1024 4096 files
Max locked memory 65536 65536 bytes
Max address space unlimited unlimited bytes
Max file locks unlimited unlimited locks
Max pending signals 13633 13633 signals
Max msgqueue size 819200 819200 bytes
Max nice priority 0 0
Max realtime priority 0 0
Max realtime timeout unlimited unlimited us
这里是top命令的部分输出（注意/usr/bin/Tsw，从顶部数第三个过程）：
Mem: 1082976K used, 990736K free, 0K shrd, 128K buff, 28136K cached
CPU: 0% usr 4% sys 0% nic 95% idle 0% io 0% irq 0% sirq
Load average: 1.07 0.36 0.13 1/242 2007
PID PPID USER STAT VSZ %VSZ %CPU COMMAND
1730 1690 root S 179m 9% 2% /usr/bin/btsvc_main_9300
585 1 root S 45784 2% 2% /usr/bin/brsCore --test-software
1691 1 root S 997m 49% 0% /usr/bin/Tsw
1941 1 root S 121m 6% 0% /usr/sbin/unifi_helper_tsw --wifi-ptest --wifi-char-device /dev/unifiudi0 --wifi-ptest-firmware ptest/firmware/ptest_unifi_93xx_a07_ptdl.xbv --wifi-ptest-profile ptest/profile/unitest_profile_CSRC9xxx_Cust_BGA.txt --log-level-text CsrWifiPtestApp..A
1687 1683 root S 119m 6% 0% /usr/sbin/unifi_helper_tsw --wifi-char-device /dev/unifi0 --wifi-on --wifi-restart-on-error --wifi-exit-on-error --wifi-exit-on-unplug --wifi-address 00:1C:C1:A2:5D:FF --wifi-mib --wifi-add-interface ff:ff:ff:ff:ff:ff
1693 1 root S 70452 3% 0% /usr/bin/avTSWCdspAudio.exe /usr/lib/audiomanager/routing/libavPluginRoutingDirana.so
1219 1 root S 66740 3% 0% /usr/bin/TSWNav_GNSS
1215 1 root S 63460 3% 0% /usr/bin/dlt-system -c /etc/dlt-system.conf
1039 1 root S 50464 2% 0% /usr/bin/avDiranaBoot.exe -t DIRANA3 -p /run/audio/dirana_boot.pipe -r 0 -d 0
1216 1 root S 48400 2% 0% /usr/bin/RadioAppTSW
1493 1 root S 47184 2% 0% /usr/bin/ssw_pers_pccl_hwi_svc
1494 1 root S 47180 2% 0% /usr/bin/ssw_pers_pccl_early_svc
1690 1 root S 35672 2% 0% /usr/bin/btsvc_main_9300
1692 1 root S 30516 1% 0% /usr/bin/tsw-apple-authic-info
1 0 root S 30060 1% 0% {systemd} /sbin/init
1225 1 root S 28224 1% 0% /usr/bin/TSWNav_Gyro
1224 1 root S 28220 1% 0% /usr/bin/TSWNav_Accel
1212 1 root S 26968 1% 0% /usr/bin/tsw-ipc-sample
793 1 root S 19532 1% 0% /usr/bin/ssw_pers_nba_svc
622 1 root S 6656 0% 0% /usr/lib/systemd/systemd-journald
1232 1 root S 4440 0% 0% /usr/sbin/sshd -D
746 1 root S 3448 0% 0% /usr/lib/systemd/systemd-udevd
2003 1691 root S 2960 0% 0% sh -c mount -o remount, rw / && cd usr/bin && top -b -n 1 > statistics_after.txt
2007 2003 root R 2960 0% 0% top -b -n 1
1682 30 root S 2960 0% 0% {unififw} /bin/sh /usr/sbin/unififw 0 2
1683 1682 root S 2960 0% 0% {unififw} /bin/sh /usr/sbin/unififw 0 2
1209 1 root S 2708 0% 0% /usr/bin/dlt-daemon
1694 1 root S 2660 0% 0% /usr/sbin/conn_wifi_tsw
1297 1 messageb S 2552 0% 0% /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
1685 1682 root S 1820 0% 0% logger -t unififw -p daemon.notice
1625 1 root S 1816 0% 0% ldattach -8e1s 2000000 19 /dev/ttymxc1
1161 2 root SW 0 0% 0% [irq/65-2010000.]
8 2 root SW 0 0% 0% [rcu_preempt]
1629 2 root SW 0 0% 0% [hydra-sdio-io]
482 2 root SW 0 0% 0% [kworker/u8:2]
6 2 root SW 0 0% 0% [kworker/u8:0]
560 2 root SW 0 0% 0% [ubi_bgt0d]
1577 2 root SW 0 0% 0% [file_server_thr]
699 2 root SW 0 0% 0% [rtp_parser]
754 2 root SW 0 0% 0% [rtp_isr_data_th]
1464 2 root SW 0 0% 0% [mmcqd/1]
3 2 root SW 0 0% 0% [ksoftirqd/0]
701 2 root SW 0 0% 0% [rtp_write_threa]
755 2 root SW 0 0% 0% [spi_send_thread]
756 2 root SW 0 0% 0% [rtp_parser_thre]
1163 2 root SW 0 0% 0% [spi2]
1387 2 root SW 0 0% 0% [irq/54-mmc0]
1630 2 root SW 0 0% 0% [hydra/complete]
30 2 root SW 0 0% 0% [kworker/u8:1]
1210 2 root SW 0 0% 0% [kworker/0:2]
2 0 root SW 0 0% 0% [kthreadd]
4 2 root SW 0 0% 0% [kworker/0:0]
5 2 root SW< 0 0% 0% [kworker/0:0H]
7 2 root SW 0 0% 0% [migration/0]
9 2 root SW 0 0% 0% [rcu_bh]
10 2 root SW 0 0% 0% [rcu_sched]
11 2 root SW 0 0% 0% [watchdog/0]
12 2 root SW 0 0% 0% [watchdog/1]
13 2 root SW 0 0% 0% [migration/1]
14 2 root SW 0 0% 0% [ksoftirqd/1]
15 2 root SW 0 0% 0% [kworker/1:0]
16 2 root SW< 0 0% 0% [kworker/1:0H]
17 2 root SW 0 0% 0% [watchdog/2]
18 2 root SW 0 0% 0% [migration/2]
19 2 root SW 0 0% 0% [ksoftirqd/2]
20 2 root SW 0 0% 0% [kworker/2:0]
21 2 root SW< 0 0% 0% [kworker/2:0H]
22 2 root SW 0 0% 0% [watchdog/3]
23 2 root SW 0 0% 0% [migration/3]
24 2 root SW 0 0% 0% [ksoftirqd/3]
25 2 root SW 0 0% 0% [kworker/3:0]
26 2 root SW< 0 0% 0% [kworker/3:0H]
27 2 root SW< 0 0% 0% [khelper]
28 2 root SW 0 0% 0% [kdevtmpfs]
29 2 root SW< 0 0% 0% [netns]
37 2 root SW 0 0% 0% [kworker/0:1]
38 2 root SW 0 0% 0% [kworker/1:1]
39 2 root SW 0 0% 0% [kworker/2:1]
40 2 root SW 0 0% 0% [kworker/3:1]
241 2 root SW< 0 0% 0% [writeback]
243 2 root SW< 0 0% 0% [bioset]
245 2 root SW< 0 0% 0% [kblockd]
279 2 root SW 0 0% 0% [khubd]
307 2 root SW 0 0% 0% [ipu1_task]
308 2 root SW 0 0% 0% [ipu1_task]
309 2 root SW 0 0% 0% [ipu2_task]
310 2 root SW 0 0% 0% [ipu2_task]
343 2 root SW 0 0% 0% [kswapd0]
402 2 root SW 0 0% 0% [fsnotify_mark]
406 2 root SW< 0 0% 0% [crypto]
416 2 root SW< 0 0% 0% [shm_workqueue]
429 2 root SW 0 0% 0% [kworker/2:2]
474 2 root SW< 0 0% 0% [usbdiag_queue]
481 2 root SW< 0 0% 0% [ci_otg]
511 2 root SW< 0 0% 0% [deferwq]
544 2 root SW 0 0% 0% [gpmi_statistics]
700 2 root SW< 0 0% 0% [rtp_admin]
753 2 root SW 0 0% 0% [spi0]
795 2 root SW 0 0% 0% [kworker/1:2]
1040 2 root SW 0 0% 0% [kworker/3:2]
1152 2 root SW 0 0% 0% [spi1]
1177 2 root SW 0 0% 0% [spi4]
1269 2 root SW< 0 0% 0% [vpu_wq]
1406 2 root SW 0 0% 0% [ubifs_bgt0_60]
1409 2 root SW 0 0% 0% [irq/56-mmc1]
1413 2 root SW 0 0% 0% [kworker/u8:3]
1465 2 root SW 0 0% 0% [mmcqd/1boot0]
1466 2 root SW 0 0% 0% [mmcqd/1boot1]
1467 2 root SW 0 0% 0% [mmcqd/1rpmb]
1480 2 root SW< 0 0% 0% [kworker/0:1H]
1482 2 root SW< 0 0% 0% [kworker/2:1H]
1486 2 root SW< 0 0% 0% [kworker/1:1H]
1533 2 root SW 0 0% 0% [jbd2/mmcblk1p3-]
1534 2 root SW< 0 0% 0% [ext4-dio-unwrit]
1536 2 root SW 0 0% 0% [jbd2/mmcblk1p2-]
1537 2 root SW< 0 0% 0% [ext4-dio-unwrit]
1578 2 root SW< 0 0% 0% [coredump_wq]
1631 2 root SW 0 0% 0% [service_mgr_thr]
1679 2 root SW< 0 0% 0% [unifi_workq]
1717 2 root SW 0 0% 0% [ubifs_bgt0_50]
1758 2 root SW 0 0% 0% [ubifs_bgt0_17]
1759 2 root SW 0 0% 0% [UNIFI_BH]
1766 2 root SW 0 0% 0% [hydra/complete]
1936 2 root SW 0 0% 0% [reader]
1937 2 root SW 0 0% 0% [writer]
我是这样分配的：
// RAM_SIZE = 1.5 Gb
// RAM_BLOCK_TEST = 2 Mb
#define RAM_SIZE (1024U * 1024U * 1536U)
#define RAM_BLOCK_TEST (1024U * 1024U * 2U)
uint32_t uiMemBlockCount = 0;
// uiLoopNr = 768
uint32_t uiLoopNr = (uint32_t)RAM_SIZE/(uint32_t)RAM_BLOCK_TEST;
uint8_t* pcMemArray[uiLoopNr];
for(uiMemBlockCount = 0; uiMemBlockCount < uiLoopNr; uiMemBlockCount++)
{
pcMemArray[uiMemBlockCount] = (uint8_t*)calloc(RAM_BLOCK_TEST, sizeof(uint8_t));
if (NULL == pcMemArray[uiMemBlockCount])
{
printf("Allocated %u block(s) of memory with %d size", uiMemBlockCount, RAM_BLOCK_TEST);
break;
}
}
也许 Linux OS 中还有其他限制不允许我这样做？ 谢谢！
我找到问题了。
Virtual kernel memory layout:
vector : 0xffff0000 - 0xffff1000 ( 4 kB)
fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
vmalloc : 0xc0800000 - 0xff000000 (1000 MB)
lowmem : 0x40000000 - 0xc0000000 (2048 MB)
modules : 0x3f000000 - 0x40000000 ( 16 MB)
.text : 0x40008000 - 0x40411ef4 (4136 kB)
.init : 0x40412000 - 0x4043ce80 ( 172 kB)
.data : 0x4043e000 - 0x404607c0 ( 138 kB)
.bss : 0x404607c0 - 0x40498208 ( 223 kB)
lowmem 从 0x40000000 开始。
所以我每个进程的虚拟内存不能超过 1 Gb。
这可以在内核配置中使用 CONFIG_PAGE_OFFSET 进行更改。