block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG [Linux 5.3]

This Linux kernel change "block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG" is included in the Linux 5.3 release. This change is authored by Christoph Hellwig <hch [at] lst.de> on Thu Jun 6 12:26:24 2019 +0200. The commit for this change in Linux stable tree is 8060c47 (patch).

block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG

This option is entirely bfq specific, give it an appropinquate name.

Also make it depend on CONFIG_BFQ_GROUP_IOSCHED in Kconfig, as all
the functionality already does so anyway.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

There are 78 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 Documentation/block/bfq-iosched.txt          | 12 ++++++------
 Documentation/cgroup-v1/blkio-controller.txt | 12 ++++++------
 block/Kconfig.iosched                        |  7 +++++++
 block/bfq-cgroup.c                           | 27 +++++++++++++--------------
 block/bfq-iosched.c                          |  8 ++++----
 block/bfq-iosched.h                          |  4 ++--
 init/Kconfig                                 |  8 --------
 7 files changed, 38 insertions(+), 40 deletions(-)

diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt
index 1a0f2ac0..f02163f 100644
--- a/Documentation/block/bfq-iosched.txt
+++ b/Documentation/block/bfq-iosched.txt
@@ -38,13 +38,13 @@ stack). To give an idea of the limits with BFQ, on slow or average
 CPUs, here are, first, the limits of BFQ for three different CPUs, on,
 respectively, an average laptop, an old desktop, and a cheap embedded
 system, in case full hierarchical support is enabled (i.e.,
-CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_DEBUG_BLK_CGROUP is not
+CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_BFQ_CGROUP_DEBUG is not
 set (Section 4-2):
 - Intel i7-4850HQ: 400 KIOPS
 - AMD A8-3850: 250 KIOPS
 - ARM CortexTM-A53 Octa-core: 80 KIOPS

-If CONFIG_DEBUG_BLK_CGROUP is set (and of course full hierarchical
+If CONFIG_BFQ_CGROUP_DEBUG is set (and of course full hierarchical
 support is enabled), then the sustainable throughput with BFQ
 decreases, because all blkio.bfq* statistics are created and updated
 (Section 4-2). For BFQ, this leads to the following maximum
@@ -537,19 +537,19 @@ or io.bfq.weight.

 As for cgroups-v1 (blkio controller), the exact set of stat files
 created, and kept up-to-date by bfq, depends on whether
-CONFIG_DEBUG_BLK_CGROUP is set. If it is set, then bfq creates all
+CONFIG_BFQ_CGROUP_DEBUG is set. If it is set, then bfq creates all
 the stat files documented in
 Documentation/cgroup-v1/blkio-controller.txt. If, instead,
-CONFIG_DEBUG_BLK_CGROUP is not set, then bfq creates only the files
+CONFIG_BFQ_CGROUP_DEBUG is not set, then bfq creates only the files
 blkio.bfq.io_service_bytes
 blkio.bfq.io_service_bytes_recursive
 blkio.bfq.io_serviced
 blkio.bfq.io_serviced_recursive

-The value of CONFIG_DEBUG_BLK_CGROUP greatly influences the maximum
+The value of CONFIG_BFQ_CGROUP_DEBUG greatly influences the maximum
 throughput sustainable with bfq, because updating the blkio.bfq.*
 stats is rather costly, especially for some of the stats enabled by
-CONFIG_DEBUG_BLK_CGROUP.
+CONFIG_BFQ_CGROUP_DEBUG.

 Parameters to set
 -----------------
diff --git a/Documentation/cgroup-v1/blkio-controller.txt b/Documentation/cgroup-v1/blkio-controller.txt
index d1a1b7b..78ec450 100644
--- a/Documentation/cgroup-v1/blkio-controller.txt
+++ b/Documentation/cgroup-v1/blkio-controller.txt
@@ -77,7 +77,7 @@ Various user visible config options
 CONFIG_BLK_CGROUP
    - Block IO controller.

-CONFIG_DEBUG_BLK_CGROUP
+CONFIG_BFQ_CGROUP_DEBUG
    - Debug help. Right now some additional stats file show up in cgroup
      if this option is enabled.

@@ -193,13 +193,13 @@ Proportional weight policy files
      write, sync or async.

 - blkio.avg_queue_size
-   - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
+   - Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.
      The average queue size for this cgroup over the entire time of this
      cgroup's existence. Queue size samples are taken each time one of the
      queues of this cgroup gets a timeslice.

 - blkio.group_wait_time
-   - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
+   - Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.
      This is the amount of time the cgroup had to wait since it became busy
      (i.e., went from 0 to 1 request queued) to get a timeslice for one of
      its queues. This is different from the io_wait_time which is the
@@ -210,7 +210,7 @@ Proportional weight policy files
      got a timeslice and will not include the current delta.

 - blkio.empty_time
-   - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
+   - Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.
      This is the amount of time a cgroup spends without any pending
      requests when not being served, i.e., it does not include any time
      spent idling for one of the queues of the cgroup. This is in
@@ -219,7 +219,7 @@ Proportional weight policy files
      time it had a pending request and will not include the current delta.

 - blkio.idle_time
-   - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.
+   - Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.
      This is the amount of time spent by the IO scheduler idling for a
      given cgroup in anticipation of a better request than the existing ones
      from other queues/cgroups. This is in nanoseconds. If this is read
@@ -228,7 +228,7 @@ Proportional weight policy files
      the current delta.

 - blkio.dequeue
-   - Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y. This
+   - Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y. This
      gives the statistics about how many a times a group was dequeued
      from service tree of the device. First two fields specify the major
      and minor number of the device and third field specifies the number
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 4626b88..7a6b2f2 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -36,6 +36,13 @@ config BFQ_GROUP_IOSCHED
        Enable hierarchical scheduling in BFQ, using the blkio
        (cgroups-v1) or io (cgroups-v2) controller.

+config BFQ_CGROUP_DEBUG
+   bool "BFQ IO controller debugging"
+   depends on BFQ_GROUP_IOSCHED
+   ---help---
+   Enable some debugging help. Currently it exports additional stat
+   files in a cgroup which can be useful for debugging.
+
 endmenu

 endif
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index d843024..0f6cd68 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -15,8 +15,7 @@

 #include "bfq-iosched.h"

-#if defined(CONFIG_BFQ_GROUP_IOSCHED) &&  defined(CONFIG_DEBUG_BLK_CGROUP)
-
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
 static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)
 {
    int ret;
@@ -253,7 +252,7 @@ void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
                io_start_time_ns - start_time_ns);
 }

-#else /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
+#else /* CONFIG_BFQ_CGROUP_DEBUG */

 void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
                  unsigned int op) { }
@@ -267,7 +266,7 @@ void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { }
 void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
 void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) { }

-#endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */

 #ifdef CONFIG_BFQ_GROUP_IOSCHED

@@ -351,7 +350,7 @@ void bfqg_and_blkg_put(struct bfq_group *bfqg)
 /* @stats = 0 */
 static void bfqg_stats_reset(struct bfqg_stats *stats)
 {
-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    /* queued stats shouldn't be cleared */
    blkg_rwstat_reset(&stats->merged);
    blkg_rwstat_reset(&stats->service_time);
@@ -372,7 +371,7 @@ static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
    if (!to || !from)
        return;

-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    /* queued stats shouldn't be cleared */
    blkg_rwstat_add_aux(&to->merged, &from->merged);
    blkg_rwstat_add_aux(&to->service_time, &from->service_time);
@@ -432,7 +431,7 @@ void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg)

 static void bfqg_stats_exit(struct bfqg_stats *stats)
 {
-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    blkg_rwstat_exit(&stats->merged);
    blkg_rwstat_exit(&stats->service_time);
    blkg_rwstat_exit(&stats->wait_time);
@@ -449,7 +448,7 @@ static void bfqg_stats_exit(struct bfqg_stats *stats)

 static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
 {
-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    if (blkg_rwstat_init(&stats->merged, gfp) ||
        blkg_rwstat_init(&stats->service_time, gfp) ||
        blkg_rwstat_init(&stats->wait_time, gfp) ||
@@ -986,7 +985,7 @@ static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
    return ret ?: nbytes;
 }

-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
 static int bfqg_print_stat(struct seq_file *sf, void *v)
 {
    blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
@@ -1109,7 +1108,7 @@ static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
              0, false);
    return 0;
 }
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */

 struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
 {
@@ -1157,7 +1156,7 @@ struct cftype bfq_blkcg_legacy_files[] = {
        .private = (unsigned long)&blkcg_policy_bfq,
        .seq_show = blkg_print_stat_ios,
    },
-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    {
        .name = "bfq.time",
        .private = offsetof(struct bfq_group, stats.time),
@@ -1187,7 +1186,7 @@ struct cftype bfq_blkcg_legacy_files[] = {
        .private = offsetof(struct bfq_group, stats.queued),
        .seq_show = bfqg_print_rwstat,
    },
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */

    /* the same statistics which cover the bfqg and its descendants */
    {
@@ -1200,7 +1199,7 @@ struct cftype bfq_blkcg_legacy_files[] = {
        .private = (unsigned long)&blkcg_policy_bfq,
        .seq_show = blkg_print_stat_ios_recursive,
    },
-#ifdef CONFIG_DEBUG_BLK_CGROUP
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    {
        .name = "bfq.time_recursive",
        .private = offsetof(struct bfq_group, stats.time),
@@ -1254,7 +1253,7 @@ struct cftype bfq_blkcg_legacy_files[] = {
        .private = offsetof(struct bfq_group, stats.dequeue),
        .seq_show = bfqg_print_stat,
    },
-#endif /* CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */
    { } /* terminate */
 };

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index a6bf842..44c6bbc 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -4404,7 +4404,7 @@ static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
    return rq;
 }

-#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
 static void bfq_update_dispatch_stats(struct request_queue *q,
                      struct request *rq,
                      struct bfq_queue *in_serv_queue,
@@ -4454,7 +4454,7 @@ static inline void bfq_update_dispatch_stats(struct request_queue *q,
                         struct request *rq,
                         struct bfq_queue *in_serv_queue,
                         bool idle_timer_disabled) {}
-#endif
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */

 static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)
 {
@@ -5008,7 +5008,7 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq)
    return idle_timer_disabled;
 }

-#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
 static void bfq_update_insert_stats(struct request_queue *q,
                    struct bfq_queue *bfqq,
                    bool idle_timer_disabled,
@@ -5038,7 +5038,7 @@ static inline void bfq_update_insert_stats(struct request_queue *q,
                       struct bfq_queue *bfqq,
                       bool idle_timer_disabled,
                       unsigned int cmd_flags) {}
-#endif
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */

 static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
                   bool at_head)
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index aef4fa0..584d3c9 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -783,7 +783,7 @@ struct bfq_stat {
 };

 struct bfqg_stats {
-#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
+#ifdef CONFIG_BFQ_CGROUP_DEBUG
    /* number of ios merged */
    struct blkg_rwstat      merged;
    /* total time spent on device in ns, may not be accurate w/ queueing */
@@ -811,7 +811,7 @@ struct bfqg_stats {
    u64             start_idle_time;
    u64             start_empty_time;
    uint16_t            flags;
-#endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
+#endif /* CONFIG_BFQ_CGROUP_DEBUG */
 };

 #ifdef CONFIG_BFQ_GROUP_IOSCHED
diff --git a/init/Kconfig b/init/Kconfig
index 0e23443..a41d8fb 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -799,14 +799,6 @@ config BLK_CGROUP

    See Documentation/cgroup-v1/blkio-controller.txt for more information.

-config DEBUG_BLK_CGROUP
-   bool "IO controller debugging"
-   depends on BLK_CGROUP
-   default n
-   ---help---
-   Enable some debugging help. Currently it exports additional stat
-   files in a cgroup which can be useful for debugging.
-
 config CGROUP_WRITEBACK
    bool
    depends on MEMCG && BLK_CGROUP

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