Merge pull request #200218 from Ma27/rm-kernel-4.9

linux_4_9: remove

2 files changed, 0 insertions, 796 deletions

diff --git a/pkgs/os-specific/linux/kernel/cpu-cgroup-v2-patches/4.9.patch b/pkgs/os-specific/linux/kernel/cpu-cgroup-v2-patches/4.9.patch
deleted file mode 100644
index 596718b83c432..0000000000000
--- a/pkgs/os-specific/linux/kernel/cpu-cgroup-v2-patches/4.9.patch
+++ /dev/null
@@ -1,784 +0,0 @@
-commit 280858b0bb3384b9ec06b455e196b453888bd6b8
-Author: Tejun Heo <tj@kernel.org>
-Date:   Fri Mar 11 07:31:23 2016 -0500
-
-    sched: Misc preps for cgroup unified hierarchy interface
-    
-    Make the following changes in preparation for the cpu controller
-    interface implementation for the unified hierarchy.  This patch
-    doesn't cause any functional differences.
-    
-    * s/cpu_stats_show()/cpu_cfs_stats_show()/
-    
-    * s/cpu_files/cpu_legacy_files/
-    
-    * Separate out cpuacct_stats_read() from cpuacct_stats_show().  While
-      at it, make the @val array u64 for consistency.
-    
-    Signed-off-by: Tejun Heo <tj@kernel.org>
-    Cc: Ingo Molnar <mingo@redhat.com>
-    Cc: Peter Zijlstra <peterz@infradead.org>
-    Cc: Li Zefan <lizefan@huawei.com>
-    Cc: Johannes Weiner <hannes@cmpxchg.org>
-
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index 154fd689fe02..57472485b79c 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -8705,7 +8705,7 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)
- 	return ret;
- }
- 
--static int cpu_stats_show(struct seq_file *sf, void *v)
-+static int cpu_cfs_stats_show(struct seq_file *sf, void *v)
- {
- 	struct task_group *tg = css_tg(seq_css(sf));
- 	struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
-@@ -8745,7 +8745,7 @@ static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css,
- }
- #endif /* CONFIG_RT_GROUP_SCHED */
- 
--static struct cftype cpu_files[] = {
-+static struct cftype cpu_legacy_files[] = {
- #ifdef CONFIG_FAIR_GROUP_SCHED
- 	{
- 		.name = "shares",
-@@ -8766,7 +8766,7 @@ static struct cftype cpu_files[] = {
- 	},
- 	{
- 		.name = "stat",
--		.seq_show = cpu_stats_show,
-+		.seq_show = cpu_cfs_stats_show,
- 	},
- #endif
- #ifdef CONFIG_RT_GROUP_SCHED
-@@ -8791,7 +8791,7 @@ struct cgroup_subsys cpu_cgrp_subsys = {
- 	.fork		= cpu_cgroup_fork,
- 	.can_attach	= cpu_cgroup_can_attach,
- 	.attach		= cpu_cgroup_attach,
--	.legacy_cftypes	= cpu_files,
-+	.legacy_cftypes	= cpu_legacy_files,
- 	.early_init	= true,
- };
- 
-diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
-index bc0b309c3f19..d1e5dd0b3a64 100644
---- a/kernel/sched/cpuacct.c
-+++ b/kernel/sched/cpuacct.c
-@@ -276,26 +276,33 @@ static int cpuacct_all_seq_show(struct seq_file *m, void *V)
- 	return 0;
- }
- 
--static int cpuacct_stats_show(struct seq_file *sf, void *v)
-+static void cpuacct_stats_read(struct cpuacct *ca,
-+			       u64 (*val)[CPUACCT_STAT_NSTATS])
- {
--	struct cpuacct *ca = css_ca(seq_css(sf));
--	s64 val[CPUACCT_STAT_NSTATS];
- 	int cpu;
--	int stat;
- 
--	memset(val, 0, sizeof(val));
-+	memset(val, 0, sizeof(*val));
-+
- 	for_each_possible_cpu(cpu) {
- 		u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
- 
--		val[CPUACCT_STAT_USER]   += cpustat[CPUTIME_USER];
--		val[CPUACCT_STAT_USER]   += cpustat[CPUTIME_NICE];
--		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
--		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
--		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
-+		(*val)[CPUACCT_STAT_USER]   += cpustat[CPUTIME_USER];
-+		(*val)[CPUACCT_STAT_USER]   += cpustat[CPUTIME_NICE];
-+		(*val)[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
-+		(*val)[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
-+		(*val)[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
- 	}
-+}
-+
-+static int cpuacct_stats_show(struct seq_file *sf, void *v)
-+{
-+	u64 val[CPUACCT_STAT_NSTATS];
-+	int stat;
-+
-+	cpuacct_stats_read(css_ca(seq_css(sf)), &val);
- 
- 	for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
--		seq_printf(sf, "%s %lld\n",
-+		seq_printf(sf, "%s %llu\n",
- 			   cpuacct_stat_desc[stat],
- 			   cputime64_to_clock_t(val[stat]));
- 	}
-
-commit 015cbdcb90034fd566d00de9d3d405613da3cd26
-Author: Tejun Heo <tj@kernel.org>
-Date:   Fri Mar 11 07:31:23 2016 -0500
-
-    sched: Implement interface for cgroup unified hierarchy
-    
-    While the cpu controller doesn't have any functional problems, there
-    are a couple interface issues which can be addressed in the v2
-    interface.
-    
-    * cpuacct being a separate controller.  This separation is artificial
-      and rather pointless as demonstrated by most use cases co-mounting
-      the two controllers.  It also forces certain information to be
-      accounted twice.
-    
-    * Use of different time units.  Writable control knobs use
-      microseconds, some stat fields use nanoseconds while other cpuacct
-      stat fields use centiseconds.
-    
-    * Control knobs which can't be used in the root cgroup still show up
-      in the root.
-    
-    * Control knob names and semantics aren't consistent with other
-      controllers.
-    
-    This patchset implements cpu controller's interface on the unified
-    hierarchy which adheres to the controller file conventions described
-    in Documentation/cgroups/unified-hierarchy.txt.  Overall, the
-    following changes are made.
-    
-    * cpuacct is implictly enabled and disabled by cpu and its information
-      is reported through "cpu.stat" which now uses microseconds for all
-      time durations.  All time duration fields now have "_usec" appended
-      to them for clarity.  While this doesn't solve the double accounting
-      immediately, once majority of users switch to v2, cpu can directly
-      account and report the relevant stats and cpuacct can be disabled on
-      the unified hierarchy.
-    
-      Note that cpuacct.usage_percpu is currently not included in
-      "cpu.stat".  If this information is actually called for, it can be
-      added later.
-    
-    * "cpu.shares" is replaced with "cpu.weight" and operates on the
-      standard scale defined by CGROUP_WEIGHT_MIN/DFL/MAX (1, 100, 10000).
-      The weight is scaled to scheduler weight so that 100 maps to 1024
-      and the ratio relationship is preserved - if weight is W and its
-      scaled value is S, W / 100 == S / 1024.  While the mapped range is a
-      bit smaller than the orignal scheduler weight range, the dead zones
-      on both sides are relatively small and covers wider range than the
-      nice value mappings.  This file doesn't make sense in the root
-      cgroup and isn't create on root.
-    
-    * "cpu.cfs_quota_us" and "cpu.cfs_period_us" are replaced by "cpu.max"
-      which contains both quota and period.
-    
-    * "cpu.rt_runtime_us" and "cpu.rt_period_us" are replaced by
-      "cpu.rt.max" which contains both runtime and period.
-    
-    v2: cpu_stats_show() was incorrectly using CONFIG_FAIR_GROUP_SCHED for
-        CFS bandwidth stats and also using raw division for u64.  Use
-        CONFIG_CFS_BANDWITH and do_div() instead.
-    
-        The semantics of "cpu.rt.max" is not fully decided yet.  Dropped
-        for now.
-    
-    Signed-off-by: Tejun Heo <tj@kernel.org>
-    Cc: Ingo Molnar <mingo@redhat.com>
-    Cc: Peter Zijlstra <peterz@infradead.org>
-    Cc: Li Zefan <lizefan@huawei.com>
-    Cc: Johannes Weiner <hannes@cmpxchg.org>
-
-diff --git a/kernel/sched/core.c b/kernel/sched/core.c
-index 57472485b79c..c0ae869f51c4 100644
---- a/kernel/sched/core.c
-+++ b/kernel/sched/core.c
-@@ -8784,6 +8784,139 @@ static struct cftype cpu_legacy_files[] = {
- 	{ }	/* terminate */
- };
- 
-+static int cpu_stats_show(struct seq_file *sf, void *v)
-+{
-+	cpuacct_cpu_stats_show(sf);
-+
-+#ifdef CONFIG_CFS_BANDWIDTH
-+	{
-+		struct task_group *tg = css_tg(seq_css(sf));
-+		struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth;
-+		u64 throttled_usec;
-+
-+		throttled_usec = cfs_b->throttled_time;
-+		do_div(throttled_usec, NSEC_PER_USEC);
-+
-+		seq_printf(sf, "nr_periods %d\n"
-+			   "nr_throttled %d\n"
-+			   "throttled_usec %llu\n",
-+			   cfs_b->nr_periods, cfs_b->nr_throttled,
-+			   throttled_usec);
-+	}
-+#endif
-+	return 0;
-+}
-+
-+#ifdef CONFIG_FAIR_GROUP_SCHED
-+static u64 cpu_weight_read_u64(struct cgroup_subsys_state *css,
-+			       struct cftype *cft)
-+{
-+	struct task_group *tg = css_tg(css);
-+	u64 weight = scale_load_down(tg->shares);
-+
-+	return DIV_ROUND_CLOSEST_ULL(weight * CGROUP_WEIGHT_DFL, 1024);
-+}
-+
-+static int cpu_weight_write_u64(struct cgroup_subsys_state *css,
-+				struct cftype *cftype, u64 weight)
-+{
-+	/*
-+	 * cgroup weight knobs should use the common MIN, DFL and MAX
-+	 * values which are 1, 100 and 10000 respectively.  While it loses
-+	 * a bit of range on both ends, it maps pretty well onto the shares
-+	 * value used by scheduler and the round-trip conversions preserve
-+	 * the original value over the entire range.
-+	 */
-+	if (weight < CGROUP_WEIGHT_MIN || weight > CGROUP_WEIGHT_MAX)
-+		return -ERANGE;
-+
-+	weight = DIV_ROUND_CLOSEST_ULL(weight * 1024, CGROUP_WEIGHT_DFL);
-+
-+	return sched_group_set_shares(css_tg(css), scale_load(weight));
-+}
-+#endif
-+
-+static void __maybe_unused cpu_period_quota_print(struct seq_file *sf,
-+						  long period, long quota)
-+{
-+	if (quota < 0)
-+		seq_puts(sf, "max");
-+	else
-+		seq_printf(sf, "%ld", quota);
-+
-+	seq_printf(sf, " %ld\n", period);
-+}
-+
-+/* caller should put the current value in *@periodp before calling */
-+static int __maybe_unused cpu_period_quota_parse(char *buf,
-+						 u64 *periodp, u64 *quotap)
-+{
-+	char tok[21];	/* U64_MAX */
-+
-+	if (!sscanf(buf, "%s %llu", tok, periodp))
-+		return -EINVAL;
-+
-+	*periodp *= NSEC_PER_USEC;
-+
-+	if (sscanf(tok, "%llu", quotap))
-+		*quotap *= NSEC_PER_USEC;
-+	else if (!strcmp(tok, "max"))
-+		*quotap = RUNTIME_INF;
-+	else
-+		return -EINVAL;
-+
-+	return 0;
-+}
-+
-+#ifdef CONFIG_CFS_BANDWIDTH
-+static int cpu_max_show(struct seq_file *sf, void *v)
-+{
-+	struct task_group *tg = css_tg(seq_css(sf));
-+
-+	cpu_period_quota_print(sf, tg_get_cfs_period(tg), tg_get_cfs_quota(tg));
-+	return 0;
-+}
-+
-+static ssize_t cpu_max_write(struct kernfs_open_file *of,
-+			     char *buf, size_t nbytes, loff_t off)
-+{
-+	struct task_group *tg = css_tg(of_css(of));
-+	u64 period = tg_get_cfs_period(tg);
-+	u64 quota;
-+	int ret;
-+
-+	ret = cpu_period_quota_parse(buf, &period, &quota);
-+	if (!ret)
-+		ret = tg_set_cfs_bandwidth(tg, period, quota);
-+	return ret ?: nbytes;
-+}
-+#endif
-+
-+static struct cftype cpu_files[] = {
-+	{
-+		.name = "stat",
-+		.flags = CFTYPE_NOT_ON_ROOT,
-+		.seq_show = cpu_stats_show,
-+	},
-+#ifdef CONFIG_FAIR_GROUP_SCHED
-+	{
-+		.name = "weight",
-+		.flags = CFTYPE_NOT_ON_ROOT,
-+		.read_u64 = cpu_weight_read_u64,
-+		.write_u64 = cpu_weight_write_u64,
-+	},
-+#endif
-+#ifdef CONFIG_CFS_BANDWIDTH
-+	{
-+		.name = "max",
-+		.flags = CFTYPE_NOT_ON_ROOT,
-+		.seq_show = cpu_max_show,
-+		.write = cpu_max_write,
-+	},
-+#endif
-+	{ }	/* terminate */
-+};
-+
- struct cgroup_subsys cpu_cgrp_subsys = {
- 	.css_alloc	= cpu_cgroup_css_alloc,
- 	.css_released	= cpu_cgroup_css_released,
-@@ -8792,7 +8925,15 @@ struct cgroup_subsys cpu_cgrp_subsys = {
- 	.can_attach	= cpu_cgroup_can_attach,
- 	.attach		= cpu_cgroup_attach,
- 	.legacy_cftypes	= cpu_legacy_files,
-+	.dfl_cftypes	= cpu_files,
- 	.early_init	= true,
-+#ifdef CONFIG_CGROUP_CPUACCT
-+	/*
-+	 * cpuacct is enabled together with cpu on the unified hierarchy
-+	 * and its stats are reported through "cpu.stat".
-+	 */
-+	.depends_on	= 1 << cpuacct_cgrp_id,
-+#endif
- };
- 
- #endif	/* CONFIG_CGROUP_SCHED */
-diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
-index d1e5dd0b3a64..57f390514c39 100644
---- a/kernel/sched/cpuacct.c
-+++ b/kernel/sched/cpuacct.c
-@@ -347,6 +347,31 @@ static struct cftype files[] = {
- 	{ }	/* terminate */
- };
- 
-+/* used to print cpuacct stats in cpu.stat on the unified hierarchy */
-+void cpuacct_cpu_stats_show(struct seq_file *sf)
-+{
-+	struct cgroup_subsys_state *css;
-+	u64 usage, val[CPUACCT_STAT_NSTATS];
-+
-+	css = cgroup_get_e_css(seq_css(sf)->cgroup, &cpuacct_cgrp_subsys);
-+
-+	usage = cpuusage_read(css, seq_cft(sf));
-+	cpuacct_stats_read(css_ca(css), &val);
-+
-+	val[CPUACCT_STAT_USER] *= TICK_NSEC;
-+	val[CPUACCT_STAT_SYSTEM] *= TICK_NSEC;
-+	do_div(usage, NSEC_PER_USEC);
-+	do_div(val[CPUACCT_STAT_USER], NSEC_PER_USEC);
-+	do_div(val[CPUACCT_STAT_SYSTEM], NSEC_PER_USEC);
-+
-+	seq_printf(sf, "usage_usec %llu\n"
-+		   "user_usec %llu\n"
-+		   "system_usec %llu\n",
-+		   usage, val[CPUACCT_STAT_USER], val[CPUACCT_STAT_SYSTEM]);
-+
-+	css_put(css);
-+}
-+
- /*
-  * charge this task's execution time to its accounting group.
-  *
-diff --git a/kernel/sched/cpuacct.h b/kernel/sched/cpuacct.h
-index ba72807c73d4..ddf7af466d35 100644
---- a/kernel/sched/cpuacct.h
-+++ b/kernel/sched/cpuacct.h
-@@ -2,6 +2,7 @@
- 
- extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
- extern void cpuacct_account_field(struct task_struct *tsk, int index, u64 val);
-+extern void cpuacct_cpu_stats_show(struct seq_file *sf);
- 
- #else
- 
-@@ -14,4 +15,8 @@ cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
- {
- }
- 
-+static inline void cpuacct_cpu_stats_show(struct seq_file *sf)
-+{
-+}
-+
- #endif
-
-commit 5019fe3d7ec456b58d451ef06fe1f81d7d9f28a9
-Author: Tejun Heo <tj@kernel.org>
-Date:   Fri Aug 5 12:41:01 2016 -0400
-
-    cgroup: add documentation regarding CPU controller cgroup v2 support
-    
-    Signed-off-by: Tejun Heo <tj@kernel.org>
-
-diff --git a/Documentation/cgroup-v2-cpu.txt b/Documentation/cgroup-v2-cpu.txt
-new file mode 100644
-index 000000000000..1ed7032d4472
---- /dev/null
-+++ b/Documentation/cgroup-v2-cpu.txt
-@@ -0,0 +1,368 @@
-+
-+
-+CPU Controller on Control Group v2
-+
-+August, 2016		Tejun Heo <tj@kernel.org>
-+
-+
-+While most controllers have support for cgroup v2 now, the CPU
-+controller support is not upstream yet due to objections from the
-+scheduler maintainers on the basic designs of cgroup v2.  This
-+document explains the current situation as well as an interim
-+solution, and details the disagreements and arguments.  The latest
-+version of this document can be found at the following URL.
-+
-+ https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git/tree/Documentation/cgroup-v2-cpu.txt?h=cgroup-v2-cpu
-+
-+This document was posted to the linux-kernel and cgroup mailing lists.
-+Unfortunately, no consensus was reached as of Oct, 2016.  The thread
-+can be found at the following URL.
-+
-+ http://lkml.kernel.org/r/20160805170752.GK2542@mtj.duckdns.org
-+
-+
-+CONTENTS
-+
-+1. Current Situation and Interim Solution
-+2. Disagreements and Arguments
-+  2-1. Contentious Restrictions
-+    2-1-1. Process Granularity
-+    2-1-2. No Internal Process Constraint
-+  2-2. Impact on CPU Controller
-+    2-2-1. Impact of Process Granularity
-+    2-2-2. Impact of No Internal Process Constraint
-+  2-3. Arguments for cgroup v2
-+3. Way Forward
-+4. References
-+
-+
-+1. Current Situation and Interim Solution
-+
-+All objections from the scheduler maintainers apply to cgroup v2 core
-+design, and there are no known objections to the specifics of the CPU
-+controller cgroup v2 interface.  The only blocked part is changes to
-+expose the CPU controller interface on cgroup v2, which comprises the
-+following two patches:
-+
-+ [1] sched: Misc preps for cgroup unified hierarchy interface
-+ [2] sched: Implement interface for cgroup unified hierarchy
-+
-+The necessary changes are superficial and implement the interface
-+files on cgroup v2.  The combined diffstat is as follows.
-+
-+ kernel/sched/core.c    |  149 +++++++++++++++++++++++++++++++++++++++++++++++--
-+ kernel/sched/cpuacct.c |   57 ++++++++++++------
-+ kernel/sched/cpuacct.h |    5 +
-+ 3 files changed, 189 insertions(+), 22 deletions(-)
-+
-+The patches are easy to apply and forward-port.  The following git
-+branch will always carry the two patches on top of the latest release
-+of the upstream kernel.
-+
-+ git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git/cgroup-v2-cpu
-+
-+There also are versioned branches going back to v4.4.
-+
-+ git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git/cgroup-v2-cpu-$KERNEL_VER
-+
-+While it's difficult to tell whether the CPU controller support will
-+be merged, there are crucial resource control features in cgroup v2
-+that are only possible due to the design choices that are being
-+objected to, and every effort will be made to ease enabling the CPU
-+controller cgroup v2 support out-of-tree for parties which choose to.
-+
-+
-+2. Disagreements and Arguments
-+
-+There have been several lengthy discussion threads [3][4] on LKML
-+around the structural constraints of cgroup v2.  The two that affect
-+the CPU controller are process granularity and no internal process
-+constraint.  Both arise primarily from the need for common resource
-+domain definition across different resources.
-+
-+The common resource domain is a powerful concept in cgroup v2 that
-+allows controllers to make basic assumptions about the structural
-+organization of processes and controllers inside the cgroup hierarchy,
-+and thus solve problems spanning multiple types of resources.  The
-+prime example for this is page cache writeback: dirty page cache is
-+regulated through throttling buffered writers based on memory
-+availability, and initiating batched write outs to the disk based on
-+IO capacity.  Tracking and controlling writeback inside a cgroup thus
-+requires the direct cooperation of the memory and the IO controller.
-+
-+This easily extends to other areas, such as CPU cycles consumed while
-+performing memory reclaim or IO encryption.
-+
-+
-+2-1. Contentious Restrictions
-+
-+For controllers of different resources to work together, they must
-+agree on a common organization.  This uniform model across controllers
-+imposes two contentious restrictions on the CPU controller: process
-+granularity and the no-internal-process constraint.
-+
-+
-+  2-1-1. Process Granularity
-+
-+  For memory, because an address space is shared between all threads
-+  of a process, the terminal consumer is a process, not a thread.
-+  Separating the threads of a single process into different memory
-+  control domains doesn't make semantical sense.  cgroup v2 ensures
-+  that all controller can agree on the same organization by requiring
-+  that threads of the same process belong to the same cgroup.
-+
-+  There are other reasons to enforce process granularity.  One
-+  important one is isolating system-level management operations from
-+  in-process application operations.  The cgroup interface, being a
-+  virtual filesystem, is very unfit for multiple independent
-+  operations taking place at the same time as most operations have to
-+  be multi-step and there is no way to synchronize multiple accessors.
-+  See also [5] Documentation/cgroup-v2.txt, "R-2. Thread Granularity"
-+
-+
-+  2-1-2. No Internal Process Constraint
-+
-+  cgroup v2 does not allow processes to belong to any cgroup which has
-+  child cgroups when resource controllers are enabled on it (the
-+  notable exception being the root cgroup itself).  This is because,
-+  for some resources, a resource domain (cgroup) is not directly
-+  comparable to the terminal consumer (process/task) of said resource,
-+  and so putting the two into a sibling relationship isn't meaningful.
-+
-+  - Differing Control Parameters and Capabilities
-+
-+    A cgroup controller has different resource control parameters and
-+    capabilities from a terminal consumer, be that a task or process.
-+    There are a couple cases where a cgroup control knob can be mapped
-+    to a per-task or per-process API but they are exceptions and the
-+    mappings aren't obvious even in those cases.
-+
-+    For example, task priorities (also known as nice values) set
-+    through setpriority(2) are mapped to the CPU controller
-+    "cpu.shares" values.  However, how exactly the two ranges map and
-+    even the fact that they map to each other at all are not obvious.
-+
-+    The situation gets further muddled when considering other resource
-+    types and control knobs.  IO priorities set through ioprio_set(2)
-+    cannot be mapped to IO controller weights and most cgroup resource
-+    control knobs including the bandwidth control knobs of the CPU
-+    controller don't have counterparts in the terminal consumers.
-+
-+  - Anonymous Resource Consumption
-+
-+    For CPU, every time slice consumed from inside a cgroup, which
-+    comprises most but not all of consumed CPU time for the cgroup,
-+    can be clearly attributed to a specific task or process.  Because
-+    these two types of entities are directly comparable as consumers
-+    of CPU time, it's theoretically possible to mix tasks and cgroups
-+    on the same tree levels and let them directly compete for the time
-+    quota available to their common ancestor.
-+
-+    However, the same can't be said for resource types like memory or
-+    IO: the memory consumed by the page cache, for example, can be
-+    tracked on a per-cgroup level, but due to mismatches in lifetimes
-+    of involved objects (page cache can persist long after processes
-+    are gone), shared usages and the implementation overhead of
-+    tracking persistent state, it can no longer be attributed to
-+    individual processes after instantiation.  Consequently, any IO
-+    incurred by page cache writeback can be attributed to a cgroup,
-+    but not to the individual consumers inside the cgroup.
-+
-+  For memory and IO, this makes a resource domain (cgroup) an object
-+  of a fundamentally different type than a terminal consumer
-+  (process).  A process can't be a first class object in the resource
-+  distribution graph as its total resource consumption can't be
-+  described without the containing resource domain.
-+
-+  Disallowing processes in internal cgroups avoids competition between
-+  cgroups and processes which cannot be meaningfully defined for these
-+  resources.  All resource control takes place among cgroups and a
-+  terminal consumer interacts with the containing cgroup the same way
-+  it would with the system without cgroup.
-+
-+  Root cgroup is exempt from this constraint, which is in line with
-+  how root cgroup is handled in general - it's excluded from cgroup
-+  resource accounting and control.
-+
-+
-+Enforcing process granularity and no internal process constraint
-+allows all controllers to be on the same footing in terms of resource
-+distribution hierarchy.
-+
-+
-+2-2. Impact on CPU Controller
-+
-+As indicated earlier, the CPU controller's resource distribution graph
-+is the simplest.  Every schedulable resource consumption can be
-+attributed to a specific task.  In addition, for weight based control,
-+the per-task priority set through setpriority(2) can be translated to
-+and from a per-cgroup weight.  As such, the CPU controller can treat a
-+task and a cgroup symmetrically, allowing support for any tree layout
-+of cgroups and tasks.  Both process granularity and the no internal
-+process constraint restrict how the CPU controller can be used.
-+
-+
-+  2-2-1. Impact of Process Granularity
-+
-+  Process granularity prevents tasks belonging to the same process to
-+  be assigned to different cgroups.  It was pointed out [6] that this
-+  excludes the valid use case of hierarchical CPU distribution within
-+  processes.
-+
-+  To address this issue, the rgroup (resource group) [7][8][9]
-+  interface, an extension of the existing setpriority(2) API, was
-+  proposed, which is in line with other programmable priority
-+  mechanisms and eliminates the risk of in-application configuration
-+  and system configuration stepping on each other's toes.
-+  Unfortunately, the proposal quickly turned into discussions around
-+  cgroup v2 design decisions [4] and no consensus could be reached.
-+
-+
-+  2-2-2. Impact of No Internal Process Constraint
-+
-+  The no internal process constraint disallows tasks from competing
-+  directly against cgroups.  Here is an excerpt from Peter Zijlstra
-+  pointing out the issue [10] - R, L and A are cgroups; t1, t2, t3 and
-+  t4 are tasks:
-+
-+
-+          R
-+        / | \
-+       t1 t2 A
-+           /   \
-+          t3   t4
-+
-+
-+    Is fundamentally different from:
-+
-+
-+               R
-+             /   \
-+           L       A
-+         /   \   /   \
-+        t1  t2  t3   t4
-+
-+
-+    Because if in the first hierarchy you add a task (t5) to R, all of
-+    its A will run at 1/4th of total bandwidth where before it had
-+    1/3rd, whereas with the second example, if you add our t5 to L, A
-+    doesn't get any less bandwidth.
-+
-+
-+  It is true that the trees are semantically different from each other
-+  and the symmetric handling of tasks and cgroups is aesthetically
-+  pleasing.  However, it isn't clear what the practical usefulness of
-+  a layout with direct competition between tasks and cgroups would be,
-+  considering that number and behavior of tasks are controlled by each
-+  application, and cgroups primarily deal with system level resource
-+  distribution; changes in the number of active threads would directly
-+  impact resource distribution.  Real world use cases of such layouts
-+  could not be established during the discussions.
-+
-+
-+2-3. Arguments for cgroup v2
-+
-+There are strong demands for comprehensive hierarchical resource
-+control across all major resources, and establishing a common resource
-+hierarchy is an essential step.  As with most engineering decisions,
-+common resource hierarchy definition comes with its trade-offs.  With
-+cgroup v2, the trade-offs are in the form of structural constraints
-+which, among others, restrict the CPU controller's space of possible
-+configurations.
-+
-+However, even with the restrictions, cgroup v2, in combination with
-+rgroup, covers most of identified real world use cases while enabling
-+new important use cases of resource control across multiple resource
-+types that were fundamentally broken previously.
-+
-+Furthermore, for resource control, treating resource domains as
-+objects of a different type from terminal consumers has important
-+advantages - it can account for resource consumptions which are not
-+tied to any specific terminal consumer, be that a task or process, and
-+allows decoupling resource distribution controls from in-application
-+APIs.  Even the CPU controller may benefit from it as the kernel can
-+consume significant amount of CPU cycles in interrupt context or tasks
-+shared across multiple resource domains (e.g. softirq).
-+
-+Finally, it's important to note that enabling cgroup v2 support for
-+the CPU controller doesn't block use cases which require the features
-+which are not available on cgroup v2.  Unlikely, but should anybody
-+actually rely on the CPU controller's symmetric handling of tasks and
-+cgroups, backward compatibility is and will be maintained by being
-+able to disconnect the controller from the cgroup v2 hierarchy and use
-+it standalone.  This also holds for cpuset which is often used in
-+highly customized configurations which might be a poor fit for common
-+resource domains.
-+
-+The required changes are minimal, the benefits for the target use
-+cases are critical and obvious, and use cases which have to use v1 can
-+continue to do so.
-+
-+
-+3. Way Forward
-+
-+cgroup v2 primarily aims to solve the problem of comprehensive
-+hierarchical resource control across all major computing resources,
-+which is one of the core problems of modern server infrastructure
-+engineering.  The trade-offs that cgroup v2 took are results of
-+pursuing that goal and gaining a better understanding of the nature of
-+resource control in the process.
-+
-+I believe that real world usages will prove cgroup v2's model right,
-+considering the crucial pieces of comprehensive resource control that
-+cannot be implemented without common resource domains.  This is not to
-+say that cgroup v2 is fixed in stone and can't be updated; if there is
-+an approach which better serves both comprehensive resource control
-+and the CPU controller's flexibility, we will surely move towards
-+that.  It goes without saying that discussions around such approach
-+should consider practical aspects of resource control as a whole
-+rather than absolutely focusing on a particular controller.
-+
-+Until such consensus can be reached, the CPU controller cgroup v2
-+support will be maintained out of the mainline kernel in an easily
-+accessible form.  If there is anything cgroup developers can do to
-+ease the pain, please feel free to contact us on the cgroup mailing
-+list at cgroups@vger.kernel.org.
-+
-+
-+4. References
-+
-+[1]  http://lkml.kernel.org/r/20160105164834.GE5995@mtj.duckdns.org
-+     [PATCH 1/2] sched: Misc preps for cgroup unified hierarchy interface
-+     Tejun Heo <tj@kernel.org>
-+
-+[2]  http://lkml.kernel.org/r/20160105164852.GF5995@mtj.duckdns.org
-+     [PATCH 2/2] sched: Implement interface for cgroup unified hierarchy
-+     Tejun Heo <tj@kernel.org>
-+
-+[3]  http://lkml.kernel.org/r/1438641689-14655-4-git-send-email-tj@kernel.org
-+     [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy
-+     Tejun Heo <tj@kernel.org>
-+
-+[4]  http://lkml.kernel.org/r/20160407064549.GH3430@twins.programming.kicks-ass.net
-+     Re: [PATCHSET RFC cgroup/for-4.6] cgroup, sched: implement resource group and PRIO_RGRP
-+     Peter Zijlstra <peterz@infradead.org>
-+
-+[5]  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/cgroup-v2.txt
-+     Control Group v2
-+     Tejun Heo <tj@kernel.org>
-+
-+[6]  http://lkml.kernel.org/r/CAPM31RJNy3jgG=DYe6GO=wyL4BPPxwUm1f2S6YXacQmo7viFZA@mail.gmail.com
-+     Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy
-+     Paul Turner <pjt@google.com>
-+
-+[7]  http://lkml.kernel.org/r/20160105154503.GC5995@mtj.duckdns.org
-+     [RFD] cgroup: thread granularity support for cpu controller
-+     Tejun Heo <tj@kernel.org>
-+
-+[8]  http://lkml.kernel.org/r/1457710888-31182-1-git-send-email-tj@kernel.org
-+     [PATCHSET RFC cgroup/for-4.6] cgroup, sched: implement resource group and PRIO_RGRP
-+     Tejun Heo <tj@kernel.org>
-+
-+[9]  http://lkml.kernel.org/r/20160311160522.GA24046@htj.duckdns.org
-+     Example program for PRIO_RGRP
-+     Tejun Heo <tj@kernel.org>
-+
-+[10] http://lkml.kernel.org/r/20160407082810.GN3430@twins.programming.kicks-ass.net
-+     Re: [PATCHSET RFC cgroup/for-4.6] cgroup, sched: implement resource
-+     Peter Zijlstra <peterz@infradead.org>
diff --git a/pkgs/os-specific/linux/kernel/linux-4.9.nix b/pkgs/os-specific/linux/kernel/linux-4.9.nix
deleted file mode 100644
index c58e05b485e5c..0000000000000
--- a/pkgs/os-specific/linux/kernel/linux-4.9.nix
+++ /dev/null
@@ -1,12 +0,0 @@
-{ buildPackages, fetchurl, perl, buildLinux, nixosTests, stdenv, ... } @ args:
-
-buildLinux (args // rec {
-  version = "4.9.332";
-  extraMeta.branch = "4.9";
-  extraMeta.broken = stdenv.isAarch64;
-
-  src = fetchurl {
-    url = "mirror://kernel/linux/kernel/v4.x/linux-${version}.tar.xz";
-    sha256 = "1kiqa9kw4932n5qglkyymsrak849wbbszw9rnq1aygmdinjz4c8i";
-  };
-} // (args.argsOverride or {}))