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authorKent Overstreet <kmo@daterainc.com>2014-03-18 04:15:53 +0400
committerKent Overstreet <kmo@daterainc.com>2014-03-18 23:23:35 +0400
commit0a63b66db566cffdf90182eb6e66fdd4d0479e63 (patch)
treed1284e5008b668befb8179de30aeb50d4e789177 /drivers/md/bcache/alloc.c
parent56b30770b27d54d68ad51eccc6d888282b568cee (diff)
downloadlinux-0a63b66db566cffdf90182eb6e66fdd4d0479e63.tar.xz
bcache: Rework btree cache reserve handling
This changes the bucket allocation reserves to use _real_ reserves - separate freelists - instead of watermarks, which if nothing else makes the current code saner to reason about and is going to be important in the future when we add support for multiple btrees. It also adds btree_check_reserve(), which checks (and locks) the reserves for both bucket allocation and memory allocation for btree nodes; the old code just kinda sorta assumed that since (e.g. for btree node splits) it had the root locked and that meant no other threads could try to make use of the same reserve; this technically should have been ok for memory allocation (we should always have a reserve for memory allocation (the btree node cache is used as a reserve and we preallocate it)), but multiple btrees will mean that locking the root won't be sufficient anymore, and for the bucket allocation reserve it was technically possible for the old code to deadlock. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Diffstat (limited to 'drivers/md/bcache/alloc.c')
-rw-r--r--drivers/md/bcache/alloc.c23
1 files changed, 1 insertions, 22 deletions
diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index 5ba4eaea57f4..a59ef6147fc7 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -375,6 +375,7 @@ static int bch_allocator_thread(void *arg)
}
allocator_wait(ca, bch_allocator_push(ca, bucket));
+ wake_up(&ca->set->btree_cache_wait);
wake_up(&ca->set->bucket_wait);
}
@@ -717,25 +718,3 @@ int bch_cache_allocator_start(struct cache *ca)
ca->alloc_thread = k;
return 0;
}
-
-int bch_cache_allocator_init(struct cache *ca)
-{
- /*
- * Reserve:
- * Prio/gen writes first
- * Then 8 for btree allocations
- * Then half for the moving garbage collector
- */
-#if 0
- ca->watermark[WATERMARK_PRIO] = 0;
-
- ca->watermark[WATERMARK_METADATA] = prio_buckets(ca);
-
- ca->watermark[WATERMARK_MOVINGGC] = 8 +
- ca->watermark[WATERMARK_METADATA];
-
- ca->watermark[WATERMARK_NONE] = ca->free.size / 2 +
- ca->watermark[WATERMARK_MOVINGGC];
-#endif
- return 0;
-}