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authorTejun Heo <tj@kernel.org>2015-08-19 00:55:11 +0300
committerJens Axboe <axboe@fb.com>2015-08-19 01:49:16 +0300
commit001bea73e70efdf48a9e00188cf302f6b6aed2bf (patch)
tree73797e7ac03b5e3e4fd9a3dc90c43f89b1ed57e0 /block/cfq-iosched.c
parent3e41871046bfe0ba7d122a1f14f0c1db2dca0256 (diff)
downloadlinux-001bea73e70efdf48a9e00188cf302f6b6aed2bf.tar.xz
blkcg: replace blkcg_policy->pd_size with ->pd_alloc/free_fn() methods
A blkg (blkcg_gq) represents the relationship between a cgroup and request_queue. Each active policy has a pd (blkg_policy_data) on each blkg. The pd's were allocated by blkcg core and each policy could request to allocate extra space at the end by setting blkcg_policy->pd_size larger than the size of pd. This is a bit unusual but was done this way mostly to simplify error handling and all the existing use cases could be handled this way; however, this is becoming too restrictive now that percpu memory can be allocated without blocking. This introduces two new mandatory blkcg_policy methods - pd_alloc_fn() and pd_free_fn() - which are used to allocate and release pd for a given policy. As pd allocation is now done from policy side, it can simply allocate a larger area which embeds pd at the beginning. This change makes ->pd_size pointless. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/cfq-iosched.c')
-rw-r--r--block/cfq-iosched.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 9c9ec7cc9f99..69ce2883099e 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1582,6 +1582,11 @@ static void cfq_cpd_init(const struct blkcg *blkcg)
}
}
+static struct blkg_policy_data *cfq_pd_alloc(gfp_t gfp, int node)
+{
+ return kzalloc_node(sizeof(struct cfq_group), gfp, node);
+}
+
static void cfq_pd_init(struct blkcg_gq *blkg)
{
struct cfq_group *cfqg = blkg_to_cfqg(blkg);
@@ -1618,6 +1623,11 @@ static void cfq_pd_offline(struct blkcg_gq *blkg)
cfqg_stats_xfer_dead(cfqg);
}
+static void cfq_pd_free(struct blkg_policy_data *pd)
+{
+ return kfree(pd);
+}
+
/* offset delta from cfqg->stats to cfqg->dead_stats */
static const int dead_stats_off_delta = offsetof(struct cfq_group, dead_stats) -
offsetof(struct cfq_group, stats);
@@ -4633,13 +4643,14 @@ static struct elevator_type iosched_cfq = {
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static struct blkcg_policy blkcg_policy_cfq = {
- .pd_size = sizeof(struct cfq_group),
.cpd_size = sizeof(struct cfq_group_data),
.cftypes = cfq_blkcg_files,
.cpd_init_fn = cfq_cpd_init,
+ .pd_alloc_fn = cfq_pd_alloc,
.pd_init_fn = cfq_pd_init,
.pd_offline_fn = cfq_pd_offline,
+ .pd_free_fn = cfq_pd_free,
.pd_reset_stats_fn = cfq_pd_reset_stats,
};
#endif