blkio interface has become messy over time and is currently the largest. In addition to the inconsistent naming scheme, it has multiple stat files which report more or less the same thing, a number of debug stat files which expose internal details which shouldn't have been part of the public interface in the first place, recursive and non-recursive stats and leaf and non-leaf knobs. Both recursive vs. non-recursive and leaf vs. non-leaf distinctions don't make any sense on the unified hierarchy as only leaf cgroups can contain processes. cgroups is going through a major interface revision with the unified hierarchy involving significant fundamental usage changes and given that a significant portion of the interface doesn't make sense anymore, it's a good time to reorganize the interface. As the first step, this patch renames the external visible subsystem name from "blkio" to "io". This is more concise, matches the other two major subsystem names, "cpu" and "memory", and better suited as blkcg will be involved in anything writeback related too whether an actual block device is involved or not. As the subsystem legacy_name is set to "blkio", the only userland visible change outside the unified hierarchy is that blkcg is reported as "io" instead of "blkio" in the subsystem initialized message during boot. On the unified hierarchy, blkcg now appears as "io".
Unified · Split
| @@ -2046,7 +2046,7 @@ int bio_associate_current(struct bio *bio) · 2045 unmodified lines | ||
| 2046 | 2046 | |
| 2047 | 2047 | get_io_context_active(ioc); |
| 2048 | 2048 | bio->bi_ioc = ioc; |
| 2049 | − bio->bi_css = task_get_css(current, blkio_cgrp_id); | |
| 2049 | + bio->bi_css = task_get_css(current, io_cgrp_id); | |
| 2050 | 2050 | return 0; |
| 2051 | 2051 | } |
| 2052 | 2052 | EXPORT_SYMBOL_GPL(bio_associate_current); |
| @@ -1089,12 +1089,13 @@ static int blkcg_can_attach(struct cgroup_subsys_state *css, · 1088 unmodified lines | ||
| 1089 | 1089 | return ret; |
| 1090 | 1090 | } |
| 1091 | 1091 | |
| 1092 | −struct cgroup_subsys blkio_cgrp_subsys = { | |
| 1092 | +struct cgroup_subsys io_cgrp_subsys = { | |
| 1093 | 1093 | .css_alloc = blkcg_css_alloc, |
| 1094 | 1094 | .css_offline = blkcg_css_offline, |
| 1095 | 1095 | .css_free = blkcg_css_free, |
| 1096 | 1096 | .can_attach = blkcg_can_attach, |
| 1097 | 1097 | .legacy_cftypes = blkcg_files, |
| 1098 | + .legacy_name = "blkio", | |
| 1098 | 1099 | #ifdef CONFIG_MEMCG |
| 1099 | 1100 | /* |
| 1100 | 1101 | * This ensures that, if available, memcg is automatically enabled |
| @@ -1104,7 +1105,7 @@ struct cgroup_subsys blkio_cgrp_subsys = { · 3 unmodified lines | ||
| 1104 | 1105 | .depends_on = 1 << memory_cgrp_id, |
| 1105 | 1106 | #endif |
| 1106 | 1107 | }; |
| 1107 | −EXPORT_SYMBOL_GPL(blkio_cgrp_subsys); | |
| 1108 | +EXPORT_SYMBOL_GPL(io_cgrp_subsys); | |
| 1108 | 1109 | |
| 1109 | 1110 | /** |
| 1110 | 1111 | * blkcg_activate_policy - activate a blkcg policy on a request_queue |
| @@ -1266,7 +1267,7 @@ int blkcg_policy_register(struct blkcg_policy *pol) · 155 unmodified lines | ||
| 1266 | 1267 | |
| 1267 | 1268 | /* everything is in place, add intf files for the new policy */ |
| 1268 | 1269 | if (pol->cftypes) |
| 1269 | − WARN_ON(cgroup_add_legacy_cftypes(&blkio_cgrp_subsys, | |
| 1270 | + WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys, | |
| 1270 | 1271 | pol->cftypes)); |
| 1271 | 1272 | mutex_unlock(&blkcg_pol_register_mutex); |
| 1272 | 1273 | return 0; |
| @@ -286,7 +286,7 @@ static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi · 285 unmodified lines | ||
| 286 | 286 | * %current's blkcg equals the effective blkcg of its memcg. No |
| 287 | 287 | * need to use the relatively expensive cgroup_get_e_css(). |
| 288 | 288 | */ |
| 289 | − if (likely(wb && wb->blkcg_css == task_css(current, blkio_cgrp_id))) | |
| 289 | + if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id))) | |
| 290 | 290 | return wb; |
| 291 | 291 | return NULL; |
| 292 | 292 | } |
| @@ -221,7 +221,7 @@ static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) · 220 unmodified lines | ||
| 221 | 221 | |
| 222 | 222 | static inline struct blkcg *task_blkcg(struct task_struct *tsk) |
| 223 | 223 | { |
| 224 | − return css_to_blkcg(task_css(tsk, blkio_cgrp_id)); | |
| 224 | + return css_to_blkcg(task_css(tsk, io_cgrp_id)); | |
| 225 | 225 | } |
| 226 | 226 | |
| 227 | 227 | static inline struct blkcg *bio_blkcg(struct bio *bio) |
| @@ -234,7 +234,7 @@ static inline struct blkcg *bio_blkcg(struct bio *bio) · 6 unmodified lines | ||
| 234 | 234 | static inline struct cgroup_subsys_state * |
| 235 | 235 | task_get_blkcg_css(struct task_struct *task) |
| 236 | 236 | { |
| 237 | − return task_get_css(task, blkio_cgrp_id); | |
| 237 | + return task_get_css(task, io_cgrp_id); | |
| 238 | 238 | } |
| 239 | 239 | |
| 240 | 240 | /** |
| @@ -16,7 +16,7 @@ SUBSYS(cpuacct) · 15 unmodified lines | ||
| 16 | 16 | #endif |
| 17 | 17 | |
| 18 | 18 | #if IS_ENABLED(CONFIG_BLK_CGROUP) |
| 19 | −SUBSYS(blkio) | |
| 19 | +SUBSYS(io) | |
| 20 | 20 | #endif |
| 21 | 21 | |
| 22 | 22 | #if IS_ENABLED(CONFIG_MEMCG) |
| @@ -523,7 +523,7 @@ static int cgwb_create(struct backing_dev_info *bdi, · 522 unmodified lines | ||
| 523 | 523 | int ret = 0; |
| 524 | 524 | |
| 525 | 525 | memcg = mem_cgroup_from_css(memcg_css); |
| 526 | − blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &blkio_cgrp_subsys); | |
| 526 | + blkcg_css = cgroup_get_e_css(memcg_css->cgroup, &io_cgrp_subsys); | |
| 527 | 527 | blkcg = css_to_blkcg(blkcg_css); |
| 528 | 528 | memcg_cgwb_list = mem_cgroup_cgwb_list(memcg); |
| 529 | 529 | blkcg_cgwb_list = &blkcg->cgwb_list; |
| @@ -645,7 +645,7 @@ struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, · 115 unmodified lines | ||
| 645 | 645 | |
| 646 | 646 | /* see whether the blkcg association has changed */ |
| 647 | 647 | blkcg_css = cgroup_get_e_css(memcg_css->cgroup, |
| 648 | − &blkio_cgrp_subsys); | |
| 648 | + &io_cgrp_subsys); | |
| 649 | 649 | if (unlikely(wb->blkcg_css != blkcg_css || |
| 650 | 650 | !wb_tryget(wb))) |
| 651 | 651 | wb = NULL; |