md: reduce CPU wastage on idle md array with a write-intent bitmap (8311c29d) · Commits · 戴 / test

drivers/md/bitmap.c

+17 −2

Original line number	Diff line number	Diff line
		@@ -1047,6 +1047,11 @@ void bitmap_daemon_work(struct bitmap *bitmap)
		if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
		return;
		bitmap->daemon_lastrun = jiffies;
		if (bitmap->allclean) {
		bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
		return;
		}
		bitmap->allclean = 1;

		for (j = 0; j < bitmap->chunks; j++) {
		bitmap_counter_t *bmc;
		@@ -1068,8 +1073,10 @@ void bitmap_daemon_work(struct bitmap *bitmap)
		clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);

		spin_unlock_irqrestore(&bitmap->lock, flags);
		if (need_write)
		if (need_write) {
		write_page(bitmap, page, 0);
		bitmap->allclean = 0;
		}
		continue;
		}

		@@ -1098,6 +1105,9 @@ void bitmap_daemon_work(struct bitmap *bitmap)
		/*
		if (j < 100) printk("bitmap: j=%lu, bmc = 0x%x\n", j, bmc);
		*/
		if (*bmc)
		bitmap->allclean = 0;

		if (*bmc == 2) {
		bmc=1; / maybe clear the bit next time */
		set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
		@@ -1132,6 +1142,8 @@ void bitmap_daemon_work(struct bitmap *bitmap)
		}
		}

		if (bitmap->allclean == 0)
		bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
		}

		static bitmap_counter_t bitmap_get_counter(struct bitmap bitmap,
		@@ -1226,6 +1238,7 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
		sectors -= blocks;
		else sectors = 0;
		}
		bitmap->allclean = 0;
		return 0;
		}

		@@ -1296,6 +1309,7 @@ int bitmap_start_sync(struct bitmap bitmap, sector_t offset, int blocks,
		}
		}
		spin_unlock_irq(&bitmap->lock);
		bitmap->allclean = 0;
		return rv;
		}

		@@ -1332,6 +1346,7 @@ void bitmap_end_sync(struct bitmap bitmap, sector_t offset, int blocks, int ab
		}
		unlock:
		spin_unlock_irqrestore(&bitmap->lock, flags);
		bitmap->allclean = 0;
		}

		void bitmap_close_sync(struct bitmap *bitmap)
		@@ -1399,7 +1414,7 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
		set_page_attr(bitmap, page, BITMAP_PAGE_CLEAN);
		}
		spin_unlock_irq(&bitmap->lock);

		bitmap->allclean = 0;
		}

		/* dirty the memory and file bits for bitmap chunks "s" to "e" */

include/linux/raid/bitmap.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -235,6 +235,8 @@ struct bitmap {

		unsigned long flags;

		int allclean;

		unsigned long max_write_behind; /* write-behind mode */
		atomic_t behind_writes;

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