bcache: Rework allocator reserves
We need a reserve for allocating buckets for new btree nodes - and now that
we've got multiple btrees, it really needs to be per btree.
This reworks the reserves so we've got separate freelists for each reserve
instead of watermarks, which seems to make things a bit cleaner, and it adds
some code so that btree_split() can make sure the reserve is available before it
starts.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index 9d062bc..94d346e 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -383,12 +383,12 @@
unsigned writeback_rate_p_term_inverse;
};
-enum alloc_watermarks {
- WATERMARK_PRIO,
- WATERMARK_METADATA,
- WATERMARK_MOVINGGC,
- WATERMARK_NONE,
- WATERMARK_MAX
+enum alloc_reserve {
+ RESERVE_BTREE,
+ RESERVE_PRIO,
+ RESERVE_MOVINGGC,
+ RESERVE_NONE,
+ RESERVE_NR,
};
struct cache {
@@ -400,8 +400,6 @@
struct kobject kobj;
struct block_device *bdev;
- unsigned watermark[WATERMARK_MAX];
-
struct task_struct *alloc_thread;
struct closure prio;
@@ -430,7 +428,7 @@
* because all the data they contained was overwritten), so we only
* need to discard them before they can be moved to the free list.
*/
- DECLARE_FIFO(long, free);
+ DECLARE_FIFO(long, free)[RESERVE_NR];
DECLARE_FIFO(long, free_inc);
DECLARE_FIFO(long, unused);