[PATCH 07/21] blkcg: restructure blkio_group configruation setting
Tejun Heo
tj at kernel.org
Wed Mar 28 22:51:17 UTC 2012
As part of userland interface restructuring, this patch updates
per-blkio_group configuration setting. Instead of funneling
everything through a master function which has hard-coded cases for
each config file it may handle, the common part is factored into
blkg_conf_prep() and blkg_conf_finish() and different configuration
setters are implemented using the helpers.
While this doesn't result in immediate LOC reduction, this enables
further cleanups and more modular implementation.
Signed-off-by: Tejun Heo <tj at kernel.org>
---
block/blk-cgroup.c | 274 ++++++++++++++++++++++++++++------------------------
block/blk-cgroup.h | 13 ---
2 files changed, 147 insertions(+), 140 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 5e8a818..0d4f21e 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -43,12 +43,6 @@ EXPORT_SYMBOL_GPL(blkio_root_cgroup);
static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];
-/* for encoding cft->private value on file */
-#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
-/* What policy owns the file, proportional or throttle */
-#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
-#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
-
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
{
return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
@@ -86,7 +80,7 @@ static inline void blkio_update_group_weight(struct blkio_group *blkg,
}
static inline void blkio_update_group_bps(struct blkio_group *blkg, int plid,
- u64 bps, int fileid)
+ u64 bps, int rw)
{
struct blkio_policy_type *blkiop;
@@ -96,21 +90,18 @@ static inline void blkio_update_group_bps(struct blkio_group *blkg, int plid,
if (blkiop->plid != plid)
continue;
- if (fileid == BLKIO_THROTL_read_bps_device
- && blkiop->ops.blkio_update_group_read_bps_fn)
+ if (rw == READ && blkiop->ops.blkio_update_group_read_bps_fn)
blkiop->ops.blkio_update_group_read_bps_fn(blkg->q,
blkg, bps);
- if (fileid == BLKIO_THROTL_write_bps_device
- && blkiop->ops.blkio_update_group_write_bps_fn)
+ if (rw == WRITE && blkiop->ops.blkio_update_group_write_bps_fn)
blkiop->ops.blkio_update_group_write_bps_fn(blkg->q,
blkg, bps);
}
}
-static inline void blkio_update_group_iops(struct blkio_group *blkg,
- int plid, unsigned int iops,
- int fileid)
+static inline void blkio_update_group_iops(struct blkio_group *blkg, int plid,
+ u64 iops, int rw)
{
struct blkio_policy_type *blkiop;
@@ -120,13 +111,11 @@ static inline void blkio_update_group_iops(struct blkio_group *blkg,
if (blkiop->plid != plid)
continue;
- if (fileid == BLKIO_THROTL_read_iops_device
- && blkiop->ops.blkio_update_group_read_iops_fn)
+ if (rw == READ && blkiop->ops.blkio_update_group_read_iops_fn)
blkiop->ops.blkio_update_group_read_iops_fn(blkg->q,
blkg, iops);
- if (fileid == BLKIO_THROTL_write_iops_device
- && blkiop->ops.blkio_update_group_write_iops_fn)
+ if (rw == WRITE && blkiop->ops.blkio_update_group_write_iops_fn)
blkiop->ops.blkio_update_group_write_iops_fn(blkg->q,
blkg,iops);
}
@@ -975,19 +964,40 @@ static int blkcg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft,
}
#endif /* CONFIG_DEBUG_BLK_CGROUP */
-static int blkio_policy_parse_and_set(char *buf, enum blkio_policy_id plid,
- int fileid, struct blkio_cgroup *blkcg)
+struct blkg_conf_ctx {
+ struct gendisk *disk;
+ struct blkio_group *blkg;
+ u64 v;
+};
+
+/**
+ * blkg_conf_prep - parse and prepare for per-blkg config update
+ * @blkcg: target block cgroup
+ * @input: input string
+ * @ctx: blkg_conf_ctx to be filled
+ *
+ * Parse per-blkg config update from @input and initialize @ctx with the
+ * result. @ctx->blkg points to the blkg to be updated and @ctx->v the new
+ * value. This function returns with RCU read locked and must be paired
+ * with blkg_conf_finish().
+ */
+static int blkg_conf_prep(struct blkio_cgroup *blkcg, const char *input,
+ struct blkg_conf_ctx *ctx)
+ __acquires(rcu)
{
- struct gendisk *disk = NULL;
- struct blkio_group *blkg = NULL;
- struct blkg_policy_data *pd;
- char *s[4], *p, *major_s = NULL, *minor_s = NULL;
+ struct gendisk *disk;
+ struct blkio_group *blkg;
+ char *buf, *s[4], *p, *major_s, *minor_s;
unsigned long major, minor;
int i = 0, ret = -EINVAL;
int part;
dev_t dev;
u64 temp;
+ buf = kstrdup(input, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
memset(s, 0, sizeof(s));
while ((p = strsep(&buf, " ")) != NULL) {
@@ -1037,82 +1047,42 @@ static int blkio_policy_parse_and_set(char *buf, enum blkio_policy_id plid,
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
- goto out_unlock;
- }
-
- pd = blkg->pd[plid];
-
- switch (plid) {
- case BLKIO_POLICY_PROP:
- if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
- temp > BLKIO_WEIGHT_MAX)
- goto out_unlock;
-
- pd->conf.weight = temp;
- blkio_update_group_weight(blkg, plid, temp ?: blkcg->weight);
- break;
- case BLKIO_POLICY_THROTL:
- switch(fileid) {
- case BLKIO_THROTL_read_bps_device:
- pd->conf.bps[READ] = temp;
- blkio_update_group_bps(blkg, plid, temp ?: -1, fileid);
- break;
- case BLKIO_THROTL_write_bps_device:
- pd->conf.bps[WRITE] = temp;
- blkio_update_group_bps(blkg, plid, temp ?: -1, fileid);
- break;
- case BLKIO_THROTL_read_iops_device:
- if (temp > THROTL_IOPS_MAX)
- goto out_unlock;
- pd->conf.iops[READ] = temp;
- blkio_update_group_iops(blkg, plid, temp ?: -1, fileid);
- break;
- case BLKIO_THROTL_write_iops_device:
- if (temp > THROTL_IOPS_MAX)
- goto out_unlock;
- pd->conf.iops[WRITE] = temp;
- blkio_update_group_iops(blkg, plid, temp ?: -1, fileid);
- break;
+ rcu_read_unlock();
+ put_disk(disk);
+ /*
+ * If queue was bypassing, we should retry. Do so after a
+ * short msleep(). It isn't strictly necessary but queue
+ * can be bypassing for some time and it's always nice to
+ * avoid busy looping.
+ */
+ if (ret == -EBUSY) {
+ msleep(10);
+ ret = restart_syscall();
}
- break;
- default:
- BUG();
+ goto out;
}
+
+ ctx->disk = disk;
+ ctx->blkg = blkg;
+ ctx->v = temp;
ret = 0;
-out_unlock:
- rcu_read_unlock();
out:
- put_disk(disk);
-
- /*
- * If queue was bypassing, we should retry. Do so after a short
- * msleep(). It isn't strictly necessary but queue can be
- * bypassing for some time and it's always nice to avoid busy
- * looping.
- */
- if (ret == -EBUSY) {
- msleep(10);
- return restart_syscall();
- }
+ kfree(buf);
return ret;
}
-static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
- const char *buffer)
+/**
+ * blkg_conf_finish - finish up per-blkg config update
+ * @ctx: blkg_conf_ctx intiailized by blkg_conf_prep()
+ *
+ * Finish up after per-blkg config update. This function must be paired
+ * with blkg_conf_prep().
+ */
+static void blkg_conf_finish(struct blkg_conf_ctx *ctx)
+ __releases(rcu)
{
- int ret = 0;
- char *buf;
- struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int fileid = BLKIOFILE_ATTR(cft->private);
-
- buf = kstrdup(buffer, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- ret = blkio_policy_parse_and_set(buf, plid, fileid, blkcg);
- kfree(buf);
- return ret;
+ rcu_read_unlock();
+ put_disk(ctx->disk);
}
/* for propio conf */
@@ -1140,6 +1110,32 @@ static int blkcg_print_weight(struct cgroup *cgrp, struct cftype *cft,
return 0;
}
+static int blkcg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+ struct blkg_policy_data *pd;
+ struct blkg_conf_ctx ctx;
+ int ret;
+
+ ret = blkg_conf_prep(blkcg, buf, &ctx);
+ if (ret)
+ return ret;
+
+ ret = -EINVAL;
+ pd = ctx.blkg->pd[BLKIO_POLICY_PROP];
+ if (pd && (!ctx.v || (ctx.v >= BLKIO_WEIGHT_MIN &&
+ ctx.v <= BLKIO_WEIGHT_MAX))) {
+ pd->conf.weight = ctx.v;
+ blkio_update_group_weight(ctx.blkg, BLKIO_POLICY_PROP,
+ ctx.v ?: blkcg->weight);
+ ret = 0;
+ }
+
+ blkg_conf_finish(&ctx);
+ return ret;
+}
+
static int blkcg_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
{
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
@@ -1181,39 +1177,67 @@ static u64 blkg_prfill_conf_u64(struct seq_file *sf,
static int blkcg_print_conf_u64(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
- int off;
-
- switch (BLKIOFILE_ATTR(cft->private)) {
- case BLKIO_THROTL_read_bps_device:
- off = offsetof(struct blkio_group_conf, bps[READ]);
- break;
- case BLKIO_THROTL_write_bps_device:
- off = offsetof(struct blkio_group_conf, bps[WRITE]);
- break;
- case BLKIO_THROTL_read_iops_device:
- off = offsetof(struct blkio_group_conf, iops[READ]);
- break;
- case BLKIO_THROTL_write_iops_device:
- off = offsetof(struct blkio_group_conf, iops[WRITE]);
- break;
- default:
- return -EINVAL;
- }
-
blkcg_print_blkgs(sf, cgroup_to_blkio_cgroup(cgrp),
blkg_prfill_conf_u64, BLKIO_POLICY_THROTL,
- off, false);
+ cft->private, false);
return 0;
}
+
+static int blkcg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf, int rw,
+ void (*update)(struct blkio_group *, int, u64, int))
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgrp);
+ struct blkg_policy_data *pd;
+ struct blkg_conf_ctx ctx;
+ int ret;
+
+ ret = blkg_conf_prep(blkcg, buf, &ctx);
+ if (ret)
+ return ret;
+
+ ret = -EINVAL;
+ pd = ctx.blkg->pd[BLKIO_POLICY_THROTL];
+ if (pd) {
+ *(u64 *)((void *)&pd->conf + cft->private) = ctx.v;
+ update(ctx.blkg, BLKIO_POLICY_THROTL, ctx.v ?: -1, rw);
+ ret = 0;
+ }
+
+ blkg_conf_finish(&ctx);
+ return ret;
+}
+
+static int blkcg_set_conf_bps_r(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ return blkcg_set_conf_u64(cgrp, cft, buf, READ, blkio_update_group_bps);
+}
+
+static int blkcg_set_conf_bps_w(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ return blkcg_set_conf_u64(cgrp, cft, buf, WRITE, blkio_update_group_bps);
+}
+
+static int blkcg_set_conf_iops_r(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ return blkcg_set_conf_u64(cgrp, cft, buf, READ, blkio_update_group_iops);
+}
+
+static int blkcg_set_conf_iops_w(struct cgroup *cgrp, struct cftype *cft,
+ const char *buf)
+{
+ return blkcg_set_conf_u64(cgrp, cft, buf, WRITE, blkio_update_group_iops);
+}
#endif
struct cftype blkio_files[] = {
{
.name = "weight_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
- BLKIO_PROP_weight_device),
.read_seq_string = blkcg_print_weight_device,
- .write_string = blkiocg_file_write,
+ .write_string = blkcg_set_weight_device,
.max_write_len = 256,
},
{
@@ -1276,37 +1300,33 @@ struct cftype blkio_files[] = {
#ifdef CONFIG_BLK_DEV_THROTTLING
{
.name = "throttle.read_bps_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_bps_device),
+ .private = offsetof(struct blkio_group_conf, bps[READ]),
.read_seq_string = blkcg_print_conf_u64,
- .write_string = blkiocg_file_write,
+ .write_string = blkcg_set_conf_bps_r,
.max_write_len = 256,
},
{
.name = "throttle.write_bps_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_bps_device),
+ .private = offsetof(struct blkio_group_conf, bps[WRITE]),
.read_seq_string = blkcg_print_conf_u64,
- .write_string = blkiocg_file_write,
+ .write_string = blkcg_set_conf_bps_w,
.max_write_len = 256,
},
{
.name = "throttle.read_iops_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_read_iops_device),
+ .private = offsetof(struct blkio_group_conf, iops[READ]),
.read_seq_string = blkcg_print_conf_u64,
- .write_string = blkiocg_file_write,
+ .write_string = blkcg_set_conf_iops_r,
.max_write_len = 256,
},
{
.name = "throttle.write_iops_device",
- .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
- BLKIO_THROTL_write_iops_device),
+ .private = offsetof(struct blkio_group_conf, iops[WRITE]),
.read_seq_string = blkcg_print_conf_u64,
- .write_string = blkiocg_file_write,
+ .write_string = blkcg_set_conf_iops_w,
.max_write_len = 256,
},
{
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index b67eefa..108ffbf 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -50,19 +50,6 @@ enum blkg_state_flags {
BLKG_empty,
};
-/* cgroup files owned by proportional weight policy */
-enum blkcg_file_name_prop {
- BLKIO_PROP_weight_device,
-};
-
-/* cgroup files owned by throttle policy */
-enum blkcg_file_name_throtl {
- BLKIO_THROTL_read_bps_device,
- BLKIO_THROTL_write_bps_device,
- BLKIO_THROTL_read_iops_device,
- BLKIO_THROTL_write_iops_device,
-};
-
struct blkio_cgroup {
struct cgroup_subsys_state css;
unsigned int weight;
--
1.7.7.3
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