bcache: Track dirty data by stripe
To make background writeback aware of raid5/6 stripes, we first need to
track the amount of dirty data within each stripe - we do this by
breaking up the existing sectors_dirty into per stripe atomic_ts
Signed-off-by: Kent Overstreet <koverstreet@google.com>
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 553949e..dd81547 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -9,6 +9,7 @@
#include "bcache.h"
#include "btree.h"
#include "debug.h"
+#include "writeback.h"
#include <trace/events/bcache.h>
@@ -38,7 +39,7 @@
int change = 0;
int64_t error;
- int64_t dirty = atomic_long_read(&dc->disk.sectors_dirty);
+ int64_t dirty = bcache_dev_sectors_dirty(&dc->disk);
int64_t derivative = dirty - dc->disk.sectors_dirty_last;
dc->disk.sectors_dirty_last = dirty;
@@ -183,10 +184,8 @@
}
}
-void bch_writeback_add(struct cached_dev *dc, unsigned sectors)
+void bch_writeback_add(struct cached_dev *dc)
{
- atomic_long_add(sectors, &dc->disk.sectors_dirty);
-
if (!atomic_read(&dc->has_dirty) &&
!atomic_xchg(&dc->has_dirty, 1)) {
atomic_inc(&dc->count);
@@ -205,6 +204,34 @@
}
}
+void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
+ uint64_t offset, int nr_sectors)
+{
+ struct bcache_device *d = c->devices[inode];
+ unsigned stripe_size, stripe_offset;
+ uint64_t stripe;
+
+ if (!d)
+ return;
+
+ stripe_size = 1 << d->stripe_size_bits;
+ stripe = offset >> d->stripe_size_bits;
+ stripe_offset = offset & (stripe_size - 1);
+
+ while (nr_sectors) {
+ int s = min_t(unsigned, abs(nr_sectors),
+ stripe_size - stripe_offset);
+
+ if (nr_sectors < 0)
+ s = -s;
+
+ atomic_add(s, d->stripe_sectors_dirty + stripe);
+ nr_sectors -= s;
+ stripe_offset = 0;
+ stripe++;
+ }
+}
+
/* Background writeback - IO loop */
static void dirty_io_destructor(struct closure *cl)
@@ -392,8 +419,9 @@
break;
if (KEY_DIRTY(k))
- atomic_long_add(KEY_SIZE(k),
- &dc->disk.sectors_dirty);
+ bcache_dev_sectors_dirty_add(b->c, dc->disk.id,
+ KEY_START(k),
+ KEY_SIZE(k));
} else {
btree(sectors_dirty_init, k, b, op, dc);
if (KEY_INODE(k) > dc->disk.id)