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| author | Coly Li <colyli@suse.de> | 2020-07-25 15:00:34 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-07-25 16:38:20 +0300 |
| commit | f9c32a5a900c6a9032b064aae9a5784af9d24453 (patch) | |
| tree | 22d5959162c8132bf437d64018eb6d81cca626d7 /drivers/md/bcache | |
| parent | bf6af17065079d29b9bd4e59de27cc2965e6fabf (diff) | |
| download | linux-f9c32a5a900c6a9032b064aae9a5784af9d24453.tar.xz | |
bcache: handle btree node memory allocation properly for bucket size > 8MB
Currently the bcache internal btree node occupies a whole bucket. When
loading the btree node from cache device into memory, mca_data_alloc()
will call bch_btree_keys_alloc() to allocate memory for the whole bucket
size, ilog2(b->c->btree_pages) is send to bch_btree_keys_alloc() as the
parameter 'page_order'.
c->btree_pages is set as bucket_pages() in bch_cache_set_alloc(), for
bucket size > 8MB, ilog2(b->c->btree_pages) is 12 for 4KB page size. By
default the maximum page order __get_free_pages() accepts is MAX_ORDER
(11), in this condition bch_btree_keys_alloc() will always fail.
Because of other over-page-order allocation failure fails the cache
device registration, such btree node allocation failure wasn't observed
during runtime. After other blocking page allocation failures for bucket
size > 8MB, this btree node allocation issue may trigger potentical risk
e.g. infinite dead-loop to retry btree node allocation after failure.
This patch fixes the potential problem by setting c->btree_pages to
meta_bucket_pages() in bch_cache_set_alloc(). In the condition that
bucket size > 8MB, meta_bucket_pages() will always return a number which
won't exceed the maximum page order of the buddy allocator.
Signed-off-by: Coly Li <colyli@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/bcache')
| -rw-r--r-- | drivers/md/bcache/super.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index b5ad4810367f..e4f05c4ddcdd 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1875,7 +1875,7 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb) c->nr_uuids = meta_bucket_bytes(&c->sb) / sizeof(struct uuid_entry); c->devices_max_used = 0; atomic_set(&c->attached_dev_nr, 0); - c->btree_pages = bucket_pages(c); + c->btree_pages = meta_bucket_pages(&c->sb); if (c->btree_pages > BTREE_MAX_PAGES) c->btree_pages = max_t(int, c->btree_pages / 4, BTREE_MAX_PAGES); |