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blk-cgroup: increase number of supported policies

After merging the iolatency policy, we potentially now have 4 policies being registered, but only support 3. This causes one of them to fail loading. Takashi reports that BFQ no longer works for him, because it fails to load due to policy registration failure. Bump to 5 policies, and also add a warning for when we have exceeded the global amount. If we have to touch this again, we should switch to a dynamic scheme instead.

Jens Axboe committed 8 years ago

Commit 01c5f851 parent bf935852 files · +4 −2Browse files

Unified · Split

2 files
  1. block/blk-cgroup.c +3 −1
  2. include/linux/blkdev.h +1 −1
block/blk-cgroup.c+3−1
@@ -1510,8 +1510,10 @@ int blkcg_policy_register(struct blkcg_policy *pol) · 1509 unmodified lines
1510 for (i = 0; i < BLKCG_MAX_POLS; i++)1510 for (i = 0; i < BLKCG_MAX_POLS; i++)
1511 if (!blkcg_policy[i])1511 if (!blkcg_policy[i])
1512 break;1512 break;
1513 if (i >= BLKCG_MAX_POLS)1513 if (i >= BLKCG_MAX_POLS) {
1514 pr_warn("blkcg_policy_register: BLKCG_MAX_POLS too small\n");
1514 goto err_unlock;1515 goto err_unlock;
1516 }
1515 1517
1516 /* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */1518 /* Make sure cpd/pd_alloc_fn and cpd/pd_free_fn in pairs */
1517 if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) ||1519 if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) ||
include/linux/blkdev.h+1−1
@@ -54,7 +54,7 @@ struct blk_stat_callback; · 53 unmodified lines
54 * Maximum number of blkcg policies allowed to be registered concurrently.54 * Maximum number of blkcg policies allowed to be registered concurrently.
55 * Defined here to simplify include dependency.55 * Defined here to simplify include dependency.
56 */56 */
57#define BLKCG_MAX_POLS 357#define BLKCG_MAX_POLS 5
58 58
59typedef void (rq_end_io_fn)(struct request *, blk_status_t);59typedef void (rq_end_io_fn)(struct request *, blk_status_t);
60 60