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Message-Id: <20221006220840.275-4-jonathan.derrick@linux.dev>
Date: Thu, 6 Oct 2022 16:08:40 -0600
From: Jonathan Derrick <jonathan.derrick@...ux.dev>
To: Song Liu <song@...nel.org>
Cc: <linux-raid@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
jonathan.derrick@...idigm.com, jonathanx.sk.derrick@...el.com,
Jonathan Derrick <jonathan.derrick@...ux.dev>
Subject: [PATCH 2/2] md/bitmap: Add chunk-count-based bitmap flushing
In addition to the timer, allow the bitmap flushing to be controlled by a
counter that tracks the number of dirty chunks and flushes when it exceeds a
user-defined chunk-count threshold.
This introduces a new field to the bitmap superblock and version 6.
Signed-off-by: Jonathan Derrick <jonathan.derrick@...ux.dev>
---
drivers/md/md-bitmap.c | 37 ++++++++++++++++++++++++++++++++++---
drivers/md/md-bitmap.h | 5 ++++-
drivers/md/md.h | 1 +
3 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 451259b38d25..fa6b3c71c314 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -499,6 +499,7 @@ void md_bitmap_print_sb(struct bitmap *bitmap)
pr_debug(" state: %08x\n", le32_to_cpu(sb->state));
pr_debug(" chunksize: %d B\n", le32_to_cpu(sb->chunksize));
pr_debug(" daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
+ pr_debug(" flush chunks: %d\n", le32_to_cpu(sb->daemon_flush_chunks));
pr_debug(" sync size: %llu KB\n",
(unsigned long long)le64_to_cpu(sb->sync_size)/2);
pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
@@ -581,6 +582,7 @@ static int md_bitmap_read_sb(struct bitmap *bitmap)
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
unsigned long long events;
+ unsigned int daemon_flush_chunks;
int nodes = 0;
unsigned long sectors_reserved = 0;
int err = -EINVAL;
@@ -644,7 +646,7 @@ static int md_bitmap_read_sb(struct bitmap *bitmap)
if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
reason = "bad magic";
else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
- le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
+ le32_to_cpu(sb->version) > BITMAP_MAJOR_CHUNKFLUSH)
reason = "unrecognized superblock version";
else if (chunksize < 512)
reason = "bitmap chunksize too small";
@@ -660,6 +662,9 @@ static int md_bitmap_read_sb(struct bitmap *bitmap)
goto out;
}
+ if (sb->version == cpu_to_le32(BITMAP_MAJOR_CHUNKFLUSH))
+ daemon_flush_chunks = le32_to_cpu(sb->daemon_flush_chunks);
+
/*
* Setup nodes/clustername only if bitmap version is
* cluster-compatible
@@ -720,6 +725,7 @@ static int md_bitmap_read_sb(struct bitmap *bitmap)
bitmap->events_cleared = bitmap->mddev->events;
bitmap->mddev->bitmap_info.chunksize = chunksize;
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
+ bitmap->mddev->bitmap_info.daemon_flush_chunks = daemon_flush_chunks;
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
bitmap->mddev->bitmap_info.nodes = nodes;
if (bitmap->mddev->bitmap_info.space == 0 ||
@@ -1218,6 +1224,31 @@ static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
sector_t offset, sector_t *blocks,
int create);
+static bool md_daemon_should_sleep(struct mddev *mddev)
+{
+ struct bitmap *bitmap = mddev->bitmap;
+ struct bitmap_page *bp;
+ unsigned long k, pages;
+ unsigned int count = 0;
+
+ if (time_after(jiffies, bitmap->daemon_lastrun
+ + mddev->bitmap_info.daemon_sleep))
+ return false;
+
+ if (mddev->bitmap_info.daemon_flush_chunks) {
+ bp = bitmap->counts.bp;
+ pages = bitmap->counts.pages;
+ for (k = 0; k < pages; k++)
+ if (bp[k].map && !bp[k].hijacked)
+ count += bp[k].count;
+
+ if (count >= mddev->bitmap_info.daemon_flush_chunks)
+ return false;
+ }
+
+ return true;
+}
+
/*
* bitmap daemon -- periodically wakes up to clean bits and flush pages
* out to disk
@@ -1240,8 +1271,8 @@ void md_bitmap_daemon_work(struct mddev *mddev)
mutex_unlock(&mddev->bitmap_info.mutex);
return;
}
- if (time_before(jiffies, bitmap->daemon_lastrun
- + mddev->bitmap_info.daemon_sleep))
+
+ if (md_daemon_should_sleep(mddev))
goto done;
md_bitmap_unplug(bitmap);
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index cfd7395de8fd..e0aeedbdde17 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -11,10 +11,12 @@
/* version 4 insists the bitmap is in little-endian order
* with version 3, it is host-endian which is non-portable
* Version 5 is currently set only for clustered devices
++ * Version 6 supports the flush-chunks threshold
*/
#define BITMAP_MAJOR_HI 4
#define BITMAP_MAJOR_CLUSTERED 5
#define BITMAP_MAJOR_HOSTENDIAN 3
+#define BITMAP_MAJOR_CHUNKFLUSH 6
/*
* in-memory bitmap:
@@ -135,7 +137,8 @@ typedef struct bitmap_super_s {
* reserved for the bitmap. */
__le32 nodes; /* 68 the maximum number of nodes in cluster. */
__u8 cluster_name[64]; /* 72 cluster name to which this md belongs */
- __u8 pad[256 - 136]; /* set to zero */
+ __le32 daemon_flush_chunks; /* 136 dirty chunks between flushes */
+ __u8 pad[256 - 140]; /* set to zero */
} bitmap_super_t;
/* notes:
diff --git a/drivers/md/md.h b/drivers/md/md.h
index b4e2d8b87b61..d25574e46283 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -497,6 +497,7 @@ struct mddev {
struct mutex mutex;
unsigned long chunksize;
unsigned long daemon_sleep; /* how many jiffies between updates? */
+ unsigned int daemon_flush_chunks; /* how many dirty chunks between updates */
unsigned long max_write_behind; /* write-behind mode */
int external;
int nodes; /* Maximum number of nodes in the cluster */
--
2.31.1
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