--- title: Sched_ext's Sub-Scheduler Support Now "Feature Complete"... description: Sched_ext's sub-scheduler support has reached feature completeness in Linux 7.3, allowing a root BPF scheduler to hand off a cgroup subtree to a nested... canonical: https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Sched_ext's Sub-Scheduler Support Now "Feature Complete" With Linux 7.3 | daily.dev og:description: Sched_ext's sub-scheduler support has reached feature completeness in Linux 7.3, allowing a root BPF scheduler to hand off a cgroup subtree to a nested... og:url: https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh og:image: https://api.daily.dev/og/posts/wCwJawGXH.png og:image:alt: Sched_ext's Sub-Scheduler Support Now "Feature Complete" With Linux 7.3 og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Sched_ext's Sub-Scheduler Support Now "Feature Complete" With Linux 7.3 **[Phoronix](https://daily.dev/sources/phoronix)** · 3 min read · 0 upvotes · 0 comments ## Summary Sched_ext's sub-scheduler support has reached feature completeness in Linux 7.3, allowing a root BPF scheduler to hand off a cgroup subtree to a nested sub-scheduler along with revocable CPU grants. The sub-scheduler then fully owns scheduling decisions for tasks on those CPUs, including enqueueing, preemption, and CPU frequency control—capabilities previously limited to dispatch delegation only. The release also adds rescue execution for starved tasks, fixes cgroup migration bugs causing use-after-free issues, hardens BPF arena memory validation, and resolves core scheduling race conditions that could hard-hang machines. scx_qmap now demonstrates full hierarchical sub-scheduling as a reference implementation. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What does sub-scheduler support mean for sched_ext in the Linux 7.3 kernel? It means a root BPF scheduler can hand a cgroup subtree over to a nested sub-scheduler along with revocable CPU grants, and the sub-scheduler owns all scheduling decisions for its tasks on those CPUs. Parent schedulers now grant and revoke per-CPU capabilities like enqueueing, preemption, and CPU frequency control on children, whereas previously only dispatching could be delegated. _Kernel engineers tracking sched_ext scheduling changes can follow BPF scheduler updates on daily.dev._ ### What happens to a task if its BPF scheduler loses access to the CPU it needs to run on under sched_ext? The kernel now runs such tasks directly on a small bandwidth budget rather than letting them starve until the watchdog ejects the whole scheduler. This rescue execution mechanism turns what was previously a scheduler-killing failure into bounded, controlled degradation instead of a full scheduler ejection. _Developers debugging BPF scheduler edge cases can keep up with sched_ext internals via daily.dev._ ### What core scheduling bug was fixed in the Linux 7.3 sched_ext pull request? Sched_ext dispatching could drop the rq lock inside the core-wide pick, letting interleaving selections corrupt each other's state and hard-hang the machine; the selection now restarts when the lock was released. A task ordering callback bug with swapped arguments was also fixed, and both fixes are marked for stable backporting. _Anyone maintaining custom kernel schedulers can track these stable-marked fixes through daily.dev._ ## Similar posts on daily.dev - [Linux 7.2 sched\_ext Continues Working Toward Sub-Scheduler Support](https://daily.dev/posts/linux-7-2-sched-ext-continues-working-toward-sub-scheduler-support-vr5ea8fuc) · Phoronix · 0 upvotes · 0 comments - [Linux 7.1 sched\_ext Brings cgroup Sub-Scheduler Groundwork, Idle SMT Sibling Improvement](https://daily.dev/posts/linux-7-1-sched-ext-brings-cgroup-sub-scheduler-groundwork-idle-smt-sibling-improvement-uqbkhed7j) · Phoronix · 0 upvotes · 0 comments - [Sub-Scheduler Support Could Be One Of The Most Exciting Features To Come For Linux 7.1](https://daily.dev/posts/sub-scheduler-support-could-be-one-of-the-most-exciting-features-to-come-for-linux-7-1-cb2sm10ug) · Phoronix · 0 upvotes · 0 comments - [Sched\_EXT With Linux 6.19 Improves Recovering For Misbehaving eBPF Schedulers](https://daily.dev/posts/sched-ext-with-linux-6-19-improves-recovering-for-misbehaving-ebpf-schedulers-4onfweyno) · Phoronix · 0 upvotes · 0 comments --- Tags: [#linux](https://daily.dev/tags/linux) [View this post on daily.dev](https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Sched_ext's Sub-Scheduler Support Now \"Feature Complete\" With Linux 7.3","url":"https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh"},"datePublished":"2026-08-22T10:52:47.005Z","dateModified":"2026-08-23T18:20:32.929Z","description":"Sched_ext's sub-scheduler support has reached feature completeness in Linux 7.3, allowing a root BPF scheduler to hand off a cgroup subtree to a nested...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6554675ed8a7716d9e85782ff5fa8d60?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/6554675ed8a7716d9e85782ff5fa8d60?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Phoronix","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Phoronix","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/6a26ba379dd64932830aa0c9803dd7ee","url":"https://daily.dev/sources/phoronix"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"linux","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Phoronix","item":"https://daily.dev/sources/phoronix"},{"@type":"ListItem","position":3,"name":"Sched_ext's Sub-Scheduler Support Now \"Feature Complete\" With Linux 7.3"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/sched-ext-s-sub-scheduler-support-now-feature-complete-with-linux-7-3-wcwjawgxh#faq","mainEntity":[{"@type":"Question","name":"What does sub-scheduler support mean for sched_ext in the Linux 7.3 kernel?","acceptedAnswer":{"@type":"Answer","text":"It means a root BPF scheduler can hand a cgroup subtree over to a nested sub-scheduler along with revocable CPU grants, and the sub-scheduler owns all scheduling decisions for its tasks on those CPUs. 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