[PATCH] md: increase the delay before marking metadata clean, and make it configurable (16f17b39) · Commits · 戴 / test

Documentation/md.txt

+9 −0

Original line number	Diff line number	Diff line
		@@ -207,6 +207,15 @@ All md devices contain:
		available. It will then appear at md/dev-XXX (depending on the
		name of the device) and further configuration is then possible.

		safe_mode_delay
		When an md array has seen no write requests for a certain period
		of time, it will be marked as 'clean'. When another write
		request arrive, the array is marked as 'dirty' before the write
		commenses. This is known as 'safe_mode'.
		The 'certain period' is controlled by this file which stores the
		period as a number of seconds. The default is 200msec (0.200).
		Writing a value of 0 disables safemode.

		sync_speed_min
		sync_speed_max
		This are similar to /proc/sys/dev/raid/speed_limit_{min,max}

drivers/md/md.c

+52 −2

Original line number	Diff line number	Diff line
		@@ -44,6 +44,7 @@
		#include <linux/suspend.h>
		#include <linux/poll.h>
		#include <linux/mutex.h>
		#include <linux/ctype.h>

		#include <linux/init.h>

		@@ -1977,6 +1978,54 @@ static void analyze_sbs(mddev_t * mddev)

		}

		static ssize_t
		safe_delay_show(mddev_t mddev, char page)
		{
		int msec = (mddev->safemode_delay*1000)/HZ;
		return sprintf(page, "%d.%03d\n", msec/1000, msec%1000);
		}
		static ssize_t
		safe_delay_store(mddev_t mddev, const char cbuf, size_t len)
		{
		int scale=1;
		int dot=0;
		int i;
		unsigned long msec;
		char buf[30];
		char *e;
		/* remove a period, and count digits after it */
		if (len >= sizeof(buf))
		return -EINVAL;
		strlcpy(buf, cbuf, len);
		buf[len] = 0;
		for (i=0; i<len; i++) {
		if (dot) {
		if (isdigit(buf[i])) {
		buf[i-1] = buf[i];
		scale *= 10;
		}
		buf[i] = 0;
		} else if (buf[i] == '.') {
		dot=1;
		buf[i] = 0;
		}
		}
		msec = simple_strtoul(buf, &e, 10);
		if (e == buf \|\| (e && e != '\n'))
		return -EINVAL;
		msec = (msec * 1000) / scale;
		if (msec == 0)
		mddev->safemode_delay = 0;
		else {
		mddev->safemode_delay = (msec*HZ)/1000;
		if (mddev->safemode_delay == 0)
		mddev->safemode_delay = 1;
		}
		return len;
		}
		static struct md_sysfs_entry md_safe_delay =
		__ATTR(safe_mode_delay, 0644,safe_delay_show, safe_delay_store);

		static ssize_t
		level_show(mddev_t mddev, char page)
		{
		@@ -2433,6 +2482,7 @@ static struct attribute *md_default_attrs[] = {
		&md_size.attr,
		&md_metadata.attr,
		&md_new_device.attr,
		&md_safe_delay.attr,
		NULL,
		};

		@@ -2708,7 +2758,7 @@ static int do_md_run(mddev_t * mddev)
		mddev->safemode = 0;
		mddev->safemode_timer.function = md_safemode_timeout;
		mddev->safemode_timer.data = (unsigned long) mddev;
		mddev->safemode_delay = (20 * HZ)/1000 +1; /* 20 msec delay */
		mddev->safemode_delay = (200 * HZ)/1000 +1; /* 200 msec delay */
		mddev->in_sync = 1;

		ITERATE_RDEV(mddev,rdev,tmp)
		@@ -4594,7 +4644,7 @@ void md_write_end(mddev_t *mddev)
		if (atomic_dec_and_test(&mddev->writes_pending)) {
		if (mddev->safemode == 2)
		md_wakeup_thread(mddev->thread);
		else
		else if (mddev->safemode_delay)
		mod_timer(&mddev->safemode_timer, jiffies + mddev->safemode_delay);
		}
		}

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