diff options
| author | Joe Thornber <ejt@redhat.com> | 2014-11-11 06:58:32 -0500 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2014-11-12 20:14:59 -0500 |
| commit | d1d9220cbaeecce910f3ecfeb71cc897a678eb68 (patch) | |
| tree | 5bdc1b75df308bc21321292d33fb956b0a9998cc /drivers/md/dm-cache-target.c | |
| parent | 7ae34e7778966d39f66397491eb114b613202c20 (diff) | |
dm cache: emit a warning message if there are a lot of cache blocks
Loading and saving millions of block mappings takes time. We may as
well explain what's going on, and encourage people to use a larger
cache block size.
Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-cache-target.c')
| -rw-r--r-- | drivers/md/dm-cache-target.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c index 6e36a0753105..abdd45d07bf6 100644 --- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c | |||
| @@ -2301,6 +2301,19 @@ static sector_t calculate_discard_block_size(sector_t cache_block_size, | |||
| 2301 | return discard_block_size; | 2301 | return discard_block_size; |
| 2302 | } | 2302 | } |
| 2303 | 2303 | ||
| 2304 | static void set_cache_size(struct cache *cache, dm_cblock_t size) | ||
| 2305 | { | ||
| 2306 | dm_block_t nr_blocks = from_cblock(size); | ||
| 2307 | |||
| 2308 | if (nr_blocks > (1 << 20) && cache->cache_size != size) | ||
| 2309 | DMWARN_LIMIT("You have created a cache device with a lot of individual cache blocks (%llu)\n" | ||
| 2310 | "All these mappings can consume a lot of kernel memory, and take some time to read/write.\n" | ||
| 2311 | "Please consider increasing the cache block size to reduce the overall cache block count.", | ||
| 2312 | (unsigned long long) nr_blocks); | ||
| 2313 | |||
| 2314 | cache->cache_size = size; | ||
| 2315 | } | ||
| 2316 | |||
| 2304 | #define DEFAULT_MIGRATION_THRESHOLD 2048 | 2317 | #define DEFAULT_MIGRATION_THRESHOLD 2048 |
| 2305 | 2318 | ||
| 2306 | static int cache_create(struct cache_args *ca, struct cache **result) | 2319 | static int cache_create(struct cache_args *ca, struct cache **result) |
| @@ -2356,10 +2369,10 @@ static int cache_create(struct cache_args *ca, struct cache **result) | |||
| 2356 | 2369 | ||
| 2357 | cache->sectors_per_block_shift = -1; | 2370 | cache->sectors_per_block_shift = -1; |
| 2358 | cache_size = block_div(cache_size, ca->block_size); | 2371 | cache_size = block_div(cache_size, ca->block_size); |
| 2359 | cache->cache_size = to_cblock(cache_size); | 2372 | set_cache_size(cache, to_cblock(cache_size)); |
| 2360 | } else { | 2373 | } else { |
| 2361 | cache->sectors_per_block_shift = __ffs(ca->block_size); | 2374 | cache->sectors_per_block_shift = __ffs(ca->block_size); |
| 2362 | cache->cache_size = to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift); | 2375 | set_cache_size(cache, to_cblock(ca->cache_sectors >> cache->sectors_per_block_shift)); |
| 2363 | } | 2376 | } |
| 2364 | 2377 | ||
| 2365 | r = create_cache_policy(cache, ca, error); | 2378 | r = create_cache_policy(cache, ca, error); |
| @@ -2856,7 +2869,7 @@ static int resize_cache_dev(struct cache *cache, dm_cblock_t new_size) | |||
| 2856 | return r; | 2869 | return r; |
| 2857 | } | 2870 | } |
| 2858 | 2871 | ||
| 2859 | cache->cache_size = new_size; | 2872 | set_cache_size(cache, new_size); |
| 2860 | 2873 | ||
| 2861 | return 0; | 2874 | return 0; |
| 2862 | } | 2875 | } |