[OpenWrt-Devel] [PATCH] ZRAM: enhacements including /tmp on ZRAM for Barrier Breaker

John Crispin blogic at openwrt.org
Wed Oct 22 06:39:20 EDT 2014


Hi,

a few comments inline. i am not sure if we want this inside procd
directly. maybe we should put this into fstools and then call that code
from early init. i need to think about that before i can make a decision.

	John



On 22/10/2014 10:30, Tomasz Wasiak wrote:
> Hello,
> 
> Here you are (of course it is just 1/3 of the original patch).
> ---
> diff --git a/initd/early.c b/initd/early.c
> index a9f6afb..b4a375f 100644
> --- a/initd/early.c
> +++ b/initd/early.c
> @@ -12,34 +12,130 @@
>   * GNU General Public License for more details.
>   */
>  
> -#include <sys/mount.h>
> -#include <sys/types.h>
> -#include <sys/stat.h>
> -
> -#include <stdio.h>
> +#include <errno.h>
>  #include <fcntl.h>
> -#include <unistd.h>
> +#include <stdio.h>
>  #include <stdlib.h>
> +#include <string.h>
> +#include <strings.h>
> +#include <unistd.h>
> +#include <sys/mount.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/wait.h>
>  
>  #include "../log.h"
>  #include "init.h"
>  
> +static long
> +check_ramsize(void)
> +{
> +	FILE *fp;
> +	char line[256];
> +	char *key;
> +	long val = 0;
> +
> +	fp = fopen("/proc/meminfo", "r");
> +	if(fp == NULL)
> +	{

please use this coding style ->

if (fp == NULL) {

}


> +		ERROR("Can't open /proc/meminfo: %s\n", strerror(errno));
> +		return errno;
> +	}
> +
> +	while(fgets(line, sizeof(line), fp))
> +	{

and here aswell

while () {

}

> +		key = strtok(line, ":");
> +		val = atol(strtok(NULL, " kB\n"));

what happens if strtok return NULL ?

> +
> +		if (!key || !val)
> +			continue;
> +
> +		if (!strcasecmp(key, "MemTotal"))
> +			break;
> +	}
> +
> +	fclose(fp);
> +
> +	return val;
> +}
> +
> +static int
> +mount_zram_on_tmp(void)
> +{
> +	FILE *fp;
> +	long zramsize = (check_ramsize() / 2);

where does the /2 come from ? is this just "a good value to use" or is
there a technical reason that is must always be /2 and not /X

> +	pid_t pid;
> +
> +	if(!zramsize)
> +	{
> +		ERROR("Can't read size of RAM. Assuming 16 MB.\n");
> +		zramsize = 8192;

dangerous, if the memory was not detected properly we have mayor issues
and should not do any magic with the memory. in this case we should just
continue without zram

> +	}
> +
> +	fp = fopen("/sys/block/zram0/disksize", "r+");
> +	if(fp == NULL)
> +	{
> +		ERROR("Can't open /sys/block/zram0/disksize: %s\n", strerror(errno));
> +		return errno;
> +	}
> +
> +	fprintf(fp, "%ld", (zramsize * 1024));
> +
> +	fclose(fp);
> +
> +	pid = fork();
> +
> +	if (!pid)
> +	{
> +		char *mkfs[] = { "/sbin/mke2fs", "-b", "4096", "-F", "-L", "TEMP", "-m", "0", "/dev/zram0", NULL };
> +		int fd = open("/dev/null", O_RDWR);
> +
> +		if (fd > -1) {
> +			dup2(fd, STDIN_FILENO);
> +			dup2(fd, STDOUT_FILENO);
> +			dup2(fd, STDERR_FILENO);
> +			if (fd > STDERR_FILENO)
> +				close(fd);
> +		}
> +
> +		execvp(mkfs[0], mkfs);
> +		ERROR("Can't exec /sbin/mke2fs\n");
> +		exit(-1);
> +	}
> +
> +	if (pid <= 0)
> +	{
> +		ERROR("Can't exec /sbin/mke2fs\n");
> +		return -1;
> +	} else {
> +		waitpid(pid, NULL, 0);
> +	}
> +
> +	if(mount("/dev/zram0", "/tmp", "ext2", MS_NOSUID | MS_NODEV | MS_NOATIME, "check=none,errors=continue,noquota") < 0)
> +	{
> +		ERROR("Can't mount /dev/zram0 on /tmp: %s\n", strerror(errno));
> +		return errno;
> +	}
> +
> +	LOG("Using up to %ld kB of RAM as ZRAM storage on /mnt\n", zramsize);
> +	return 0;
> +}
> +
>  static void
> -early_mounts(void)
> +mount_tmpfs_on_tmp(void)
>  {
> -	mount("proc", "/proc", "proc", MS_NOATIME, 0);
> -	mount("sysfs", "/sys", "sysfs", MS_NOATIME, 0);
> +	char line[256];
> +	long tmpfssize = (check_ramsize() / 2);

same here

>  
> -	mount("tmpfs", "/tmp", "tmpfs", MS_NOSUID | MS_NODEV | MS_NOATIME, NULL);
> -	mkdir("/tmp/run", 0777);
> -	mkdir("/tmp/lock", 0777);
> -	mkdir("/tmp/state", 0777);
> -	symlink("/tmp", "/var");
> +	if(!tmpfssize)
> +	{
> +		ERROR("Can't read size of RAM. Assuming 16 MB.\n");
> +		tmpfssize = 8192;

same here

> +	}
>  
> -	mount("tmpfs", "/dev", "tmpfs", MS_NOATIME, "mode=0755,size=512K");
> -	mkdir("/dev/shm", 0755);
> -	mkdir("/dev/pts", 0755);
> -	mount("devpts", "/dev/pts", "devpts", MS_NOATIME, "mode=600");
> +	snprintf(line, 256, "size=%ldk", tmpfssize);
> +	mount("tmpfs", "/tmp", "tmpfs", MS_NOSUID | MS_NODEV | MS_NOATIME, line);
> +	LOG("Using up to %ld kB of RAM as TMPFS storage on /tmp\n", tmpfssize);
>  }
>  
>  static void
> @@ -50,6 +146,25 @@ early_dev(void)
>  }
>  
>  static void
> +early_mounts(void)
> +{
> +	mount("proc", "/proc", "proc", MS_NOATIME, 0);
> +	mount("sysfs", "/sys", "sysfs", MS_NOATIME, 0);
> +	mount("tmpfs", "/dev", "tmpfs", MS_NOATIME, "mode=0755,size=512K");
> +	mkdir("/dev/shm", 0755);
> +	mkdir("/dev/pts", 0755);
> +	mount("devpts", "/dev/pts", "devpts", MS_NOATIME, "mode=600");
> +	early_dev();
> +
> +	if(mount_zram_on_tmp() !=0)
> +		mount_tmpfs_on_tmp();
> +	mkdir("/tmp/run", 0777);
> +	mkdir("/tmp/lock", 0777);
> +	mkdir("/tmp/state", 0777);
> +	symlink("/tmp", "/var");
> +}
> +
> +static void
>  early_console(const char *dev)
>  {
>  	struct stat s;
> @@ -89,7 +204,6 @@ early(void)
>  		return;
>  
>  	early_mounts();
> -	early_dev();
>  	early_env();
>  	early_console("/dev/console");
>  
> 
> 
> W dniu 22.10.2014 o 09:38, John Crispin pisze:
>> Hi,
>>
>> please send patches directly against the procd git tree.
>>
>> 	John
>>
>> On 22/10/2014 09:20, Tomasz Wasiak wrote:
>>> Devices with less memory are still common so why limit ZRAM usage
>>> just to swap when it could be very useful as for /tmp storage.
>>>
>>> This patch changes 3 things: - sets default number of ZRAM devices
>>> to 2 (1st for /tmp, 2nd for swap) - adds ZRAM (default) support to
>>> procd's init (TMPFS is used when ZRAM is not available - changes
>>> zram-swap so it will use /dev/zram1 for 1st CPU, /dev/zram2 for
>>> 2nd and so on as /dev/zram0 is in use for /tmp.
>>>
>>> Signed-off-by: Tomasz Wasiak <tjwasiak at gmail.com> --- 
>>> package/system/procd/patches/procd-support_for_tmp_on_zram.patch
>>> |  185 ++++++++++ package/system/zram-swap/files/zram.init
>>> |   15 
>>> target/linux/generic/patches-3.10/998_zram_make_2_devices_by_default.patch
>>> |   11 3 files changed, 203 insertions(+), 8 deletions(-)
>>>
>>> ---
>>> a/package/system/procd/patches/procd-support_for_tmo_on_zram.patch 
>>> +++
>>> b/package/system/procd/patches/procd-support_for_tmp_on_zram.patch 
>>> @@ -0,0 +1,185 @@ +--- a/initd/early.c ++++ b/initd/early.c +@@
>>> -12,34 +12,130 @@ +  * GNU General Public License for more
>>> details. +  */ + +-#include <sys/mount.h> +-#include <sys/types.h> 
>>> +-#include <sys/stat.h> +- +-#include <stdio.h> ++#include
>>> <errno.h> + #include <fcntl.h> +-#include <unistd.h> ++#include
>>> <stdio.h> + #include <stdlib.h> ++#include <string.h> ++#include
>>> <strings.h> ++#include <unistd.h> ++#include <sys/mount.h> 
>>> ++#include <sys/stat.h> ++#include <sys/types.h> ++#include
>>> <sys/wait.h> + + #include "../log.h" + #include "init.h" + ++static
>>> long ++check_ramsize(void) ++{ ++	FILE *fp; ++	char line[256]; ++
>>> char *key; ++	long val = 0; ++ ++	fp = fopen("/proc/meminfo",
>>> "r"); ++	if(fp == NULL) ++	{ ++		ERROR("Can't open /proc/meminfo:
>>> %s\n", strerror(errno)); ++		return errno; ++	} ++ ++
>>> while(fgets(line, sizeof(line), fp)) ++	{ ++		key = strtok(line,
>>> ":"); ++		val = atol(strtok(NULL, " kB\n")); ++ ++		if (!key ||
>>> !val) ++			continue; ++ ++		if (!strcasecmp(key, "MemTotal")) ++
>>> break; ++	} ++ ++	fclose(fp); ++ ++	return val; ++} ++ ++static
>>> int ++mount_zram_on_tmp(void) ++{ ++	FILE *fp; ++	long zramsize =
>>> (check_ramsize() / 2); ++	pid_t pid; ++ ++	if(!zramsize) ++	{ ++
>>> ERROR("Can't read size of RAM. Assuming 16 MB.\n"); ++		zramsize =
>>> 8192; ++	} ++ ++	fp = fopen("/sys/block/zram0/disksize", "r+"); ++
>>> if(fp == NULL) ++	{ ++		ERROR("Can't open
>>> /sys/block/zram0/disksize: %s\n", strerror(errno)); ++		return
>>> errno; ++	} ++ ++	fprintf(fp, "%ld", (zramsize * 1024)); ++ ++
>>> fclose(fp); ++ ++	pid = fork(); ++ ++	if (!pid) ++	{ ++		char
>>> *mkfs[] = { "/sbin/mke2fs", "-b", "4096", "-F", "-L", "TEMP", "-m",
>>> "0", "/dev/zram0", NULL }; ++		int fd = open("/dev/null", O_RDWR); 
>>> ++ ++		if (fd > -1) { ++			dup2(fd, STDIN_FILENO); ++			dup2(fd,
>>> STDOUT_FILENO); ++			dup2(fd, STDERR_FILENO); ++			if (fd >
>>> STDERR_FILENO) ++				close(fd); ++		} ++ ++		execvp(mkfs[0],
>>> mkfs); ++		ERROR("Can't exec /sbin/mke2fs\n"); ++		exit(-1); ++	} 
>>> ++ ++	if (pid <= 0) ++	{ ++		ERROR("Can't exec /sbin/mke2fs\n"); ++
>>> return -1; ++	} else { ++		waitpid(pid, NULL, 0); ++	} ++ ++
>>> if(mount("/dev/zram0", "/tmp", "ext2", MS_NOSUID | MS_NODEV |
>>> MS_NOATIME, "check=none,errors=continue,noquota") < 0) ++	{ ++
>>> ERROR("Can't mount /dev/zram0 on /tmp: %s\n", strerror(errno)); ++
>>> return errno; ++	} ++ ++	LOG("Using up to %ld kB of RAM as ZRAM
>>> storage on /mnt\n", zramsize); ++	return 0; ++} ++ + static void 
>>> +-early_mounts(void) ++mount_tmpfs_on_tmp(void) + { +-
>>> mount("proc", "/proc", "proc", MS_NOATIME, 0); +-	mount("sysfs",
>>> "/sys", "sysfs", MS_NOATIME, 0); ++	char line[256]; ++	long
>>> tmpfssize = (check_ramsize() / 2); + +-	mount("tmpfs", "/tmp",
>>> "tmpfs", MS_NOSUID | MS_NODEV | MS_NOATIME, NULL); +-
>>> mkdir("/tmp/run", 0777); +-	mkdir("/tmp/lock", 0777); +-
>>> mkdir("/tmp/state", 0777); +-	symlink("/tmp", "/var"); ++
>>> if(!tmpfssize) ++	{ ++		ERROR("Can't read size of RAM. Assuming 16
>>> MB.\n"); ++		tmpfssize = 8192; ++	} + +-	mount("tmpfs", "/dev",
>>> "tmpfs", MS_NOATIME, "mode=0755,size=512K"); +-	mkdir("/dev/shm",
>>> 0755); +-	mkdir("/dev/pts", 0755); +-	mount("devpts", "/dev/pts",
>>> "devpts", MS_NOATIME, "mode=600"); ++	snprintf(line, 256,
>>> "size=%ldk", tmpfssize); ++	mount("tmpfs", "/tmp", "tmpfs",
>>> MS_NOSUID | MS_NODEV | MS_NOATIME, line); ++	LOG("Using up to %ld
>>> kB of RAM as TMPFS storage on /tmp\n", tmpfssize); + } + + static
>>> void +@@ -50,6 +146,25 @@ early_dev(void) + } + + static void 
>>> ++early_mounts(void) ++{ ++	mount("proc", "/proc", "proc",
>>> MS_NOATIME, 0); ++	mount("sysfs", "/sys", "sysfs", MS_NOATIME, 0); 
>>> ++	mount("tmpfs", "/dev", "tmpfs", MS_NOATIME,
>>> "mode=0755,size=512K"); ++	mkdir("/dev/shm", 0755); ++
>>> mkdir("/dev/pts", 0755); ++	mount("devpts", "/dev/pts", "devpts",
>>> MS_NOATIME, "mode=600"); ++	early_dev(); ++ ++
>>> if(mount_zram_on_tmp() !=0) ++		mount_tmpfs_on_tmp(); ++
>>> mkdir("/tmp/run", 0777); ++	mkdir("/tmp/lock", 0777); ++
>>> mkdir("/tmp/state", 0777); ++	symlink("/tmp", "/var"); ++} ++ 
>>> ++static void + early_console(const char *dev) + { + 	struct stat
>>> s; +@@ -87,7 +202,6 @@ early(void) + 		return; + +
>>> early_mounts(); +-	early_dev(); + 	early_env(); +
>>> early_console("/dev/console"); + ---
>>> a/package/system/zram-swap/files/zram.init +++
>>> b/package/system/zram-swap/files/zram.init @@ -15,10 +15,10 @@
>>> zram_size()	# in megabytes local ram_size="$( ram_size )"
>>>
>>> if [ -z "$zram_size" ]; then -		# e.g. 6mb for 16mb-routers or 61mb
>>> for 128mb-routers -		echo $(( $ram_size / 2048 )) +		# e.g. 3200kb
>>> for 16mb-routers or 25600kb for 128mb-routers +		echo $(( $ram_size
>>> * 2 / 10 )) else -		echo "$zram_size" +		echo $(( $zram_size * 1024
>>> )) fi }
>>>
>>> @@ -54,9 +54,9 @@ zram_applicable()
>>>
>>> zram_dev() { -	local core="$1" +	local core=$(( $1 + 1 ))
>>>
>>> -	echo "/dev/zram${core:-0}" +	echo "/dev/zram${core:-1}" }
>>>
>>> zram_reset() @@ -95,10 +95,10 @@ start() zram_dev="$( zram_dev
>>> "$core" )" zram_applicable "$zram_dev" || return 1
>>>
>>> -		logger -s -t zram_start -p daemon.debug "activating '$zram_dev'
>>> for swapping ($zram_size MegaBytes)" +		logger -s -t zram_start -p
>>> daemon.debug "activating '$zram_dev' for swapping ($zram_size
>>> KiloBytes)"
>>>
>>> zram_reset "$zram_dev" "enforcing defaults" -		echo $(( $zram_size
>>> * 1024 * 1024 )) >"/sys/block/$( basename $zram_dev )/disksize" +
>>> echo $(( $zram_size * 1024 )) >"/sys/block/$( basename $zram_dev
>>> )/disksize" mkswap "$zram_dev" swapon "$zram_dev" } done @@ -120,4
>>> +120,3 @@ stop() zram_reset "$zram_dev" "claiming memory back" }
>>> done } - ---
>>> a/target/linux/generic/patches-3.10/998_zram_make_2_devices_by_default.patch
>>>
>>>
>> +++
>> b/target/linux/generic/patches-3.10/998_zram_make_2_devices_by_default.patch
>>> @@ -0,0 +1,11 @@ +--- a/drivers/staging/zram/zram_drv.c ++++
>>> b/drivers/staging/zram/zram_drv.c +@@ -40,7 +40,7 @@ static int
>>> zram_major; + struct zram *zram_devices; + + /* Module params
>>> (documentation at end) */ +-static unsigned int num_devices = 1; 
>>> ++static unsigned int num_devices = 2; + + static void
>>> zram_stat64_add(struct zram *zram, u64 *v, u64 inc) + { 
>>> _______________________________________________ openwrt-devel
>>> mailing list openwrt-devel at lists.openwrt.org 
>>> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>>>
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