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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
- Spectre/Meltdown safelisting for some Qualcomm KRYO cores
- Fix RCU splat when failing to online a CPU due to a feature mismatch
- Fix a recently introduced sparse warning in kexec()
- Fix handling of CPU erratum 1418040 for late CPUs
- Ensure hot-added memory falls within linear-mapped region
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: cpu_errata: Apply Erratum 845719 to KRYO2XX Silver
arm64: proton-pack: Add KRYO2XX silver CPUs to spectre-v2 safe-list
arm64: kpti: Add KRYO2XX gold/silver CPU cores to kpti safelist
arm64: Add MIDR value for KRYO2XX gold/silver CPU cores
arm64/mm: Validate hotplug range before creating linear mapping
arm64: smp: Tell RCU about CPUs that fail to come online
arm64: psci: Avoid printing in cpu_psci_cpu_die()
arm64: kexec_file: Fix sparse warning
arm64: errata: Fix handling of 1418040 with late CPU onlining
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The value of variable ret is overwritten on the delete branch in the
test_create_synth_event() and we care more about the above error than
this delete portion. Remove it.
Link: https://lkml.kernel.org/r/1605283360-6804-1-git-send-email-kaixuxia@tencent.com
Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, the ftrace call
will be able to set the ip of the calling function. This will improve the
performance of live kernel patching where it does not need all the regs to
be stored just to change the instruction pointer.
If all archs that support live kernel patching also support
HAVE_DYNAMIC_FTRACE_WITH_ARGS, then the architecture specific function
klp_arch_set_pc() could be made generic.
It is possible that an arch can support HAVE_DYNAMIC_FTRACE_WITH_ARGS but
not HAVE_DYNAMIC_FTRACE_WITH_REGS and then have access to live patching.
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: live-patching@vger.kernel.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Currently, the only way to get access to the registers of a function via a
ftrace callback is to set the "FL_SAVE_REGS" bit in the ftrace_ops. But as this
saves all regs as if a breakpoint were to trigger (for use with kprobes), it
is expensive.
The regs are already saved on the stack for the default ftrace callbacks, as
that is required otherwise a function being traced will get the wrong
arguments and possibly crash. And on x86, the arguments are already stored
where they would be on a pt_regs structure to use that code for both the
regs version of a callback, it makes sense to pass that information always
to all functions.
If an architecture does this (as x86_64 now does), it is to set
HAVE_DYNAMIC_FTRACE_WITH_ARGS, and this will let the generic code that it
could have access to arguments without having to set the flags.
This also includes having the stack pointer being saved, which could be used
for accessing arguments on the stack, as well as having the function graph
tracer not require its own trampoline!
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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In preparation to have arguments of a function passed to callbacks attached
to functions as default, change the default callback prototype to receive a
struct ftrace_regs as the forth parameter instead of a pt_regs.
For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they
will now need to get the pt_regs via a ftrace_get_regs() helper call. If
this is called by a callback that their ftrace_ops did not have a
FL_SAVE_REGS flag set, it that helper function will return NULL.
This will allow the ftrace_regs to hold enough just to get the parameters
and stack pointer, but without the worry that callbacks may have a pt_regs
that is not completely filled.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Sleepable hooks are never called from an NMI/interrupt context, so it
is safe to use the bpf_d_path helper in LSM programs attaching to these
hooks.
The helper is not restricted to sleepable programs and merely uses the
list of sleepable hooks as the initial subset of LSM hooks where it can
be used.
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201113005930.541956-3-kpsingh@chromium.org
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Update the set of sleepable hooks with the ones that do not trigger
a warning with might_fault() when exercised with the correct kernel
config options enabled, i.e.
DEBUG_ATOMIC_SLEEP=y
LOCKDEP=y
PROVE_LOCKING=y
This means that a sleepable LSM eBPF program can be attached to these
LSM hooks. A new helper method bpf_lsm_is_sleepable_hook is added and
the set is maintained locally in bpf_lsm.c
Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20201113005930.541956-2-kpsingh@chromium.org
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This patch enables the FENTRY/FEXIT/RAW_TP tracing program to use
the bpf_sk_storage_(get|delete) helper, so those tracing programs
can access the sk's bpf_local_storage and the later selftest
will show some examples.
The bpf_sk_storage is currently used in bpf-tcp-cc, tc,
cg sockops...etc which is running either in softirq or
task context.
This patch adds bpf_sk_storage_get_tracing_proto and
bpf_sk_storage_delete_tracing_proto. They will check
in runtime that the helpers can only be called when serving
softirq or running in a task context. That should enable
most common tracing use cases on sk.
During the load time, the new tracing_allowed() function
will ensure the tracing prog using the bpf_sk_storage_(get|delete)
helper is not tracing any bpf_sk_storage*() function itself.
The sk is passed as "void *" when calling into bpf_local_storage.
This patch only allows tracing a kernel function.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201112211313.2587383-1-kafai@fb.com
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Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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This patch adds the verifier support to recognize inlined branch conditions.
The LLVM knows that the branch evaluates to the same value, but the verifier
couldn't track it. Hence causing valid programs to be rejected.
The potential LLVM workaround: https://reviews.llvm.org/D87428
can have undesired side effects, since LLVM doesn't know that
skb->data/data_end are being compared. LLVM has to introduce extra boolean
variable and use inline_asm trick to force easier for the verifier assembly.
Instead teach the verifier to recognize that
r1 = skb->data;
r1 += 10;
r2 = skb->data_end;
if (r1 > r2) {
here r1 points beyond packet_end and
subsequent
if (r1 > r2) // always evaluates to "true".
}
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20201111031213.25109-2-alexei.starovoitov@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Current release - regressions:
- arm64: dts: fsl-ls1028a-kontron-sl28: specify in-band mode for
ENETC
Current release - bugs in new features:
- mptcp: provide rmem[0] limit offset to fix oops
Previous release - regressions:
- IPv6: Set SIT tunnel hard_header_len to zero to fix path MTU
calculations
- lan743x: correctly handle chips with internal PHY
- bpf: Don't rely on GCC __attribute__((optimize)) to disable GCSE
- mlx5e: Fix VXLAN port table synchronization after function reload
Previous release - always broken:
- bpf: Zero-fill re-used per-cpu map element
- fix out-of-order UDP packets when forwarding with UDP GSO fraglists
turned on:
- fix UDP header access on Fast/frag0 UDP GRO
- fix IP header access and skb lookup on Fast/frag0 UDP GRO
- ethtool: netlink: add missing netdev_features_change() call
- net: Update window_clamp if SOCK_RCVBUF is set
- igc: Fix returning wrong statistics
- ch_ktls: fix multiple leaks and corner cases in Chelsio TLS offload
- tunnels: Fix off-by-one in lower MTU bounds for ICMP/ICMPv6 replies
- r8169: disable hw csum for short packets on all chip versions
- vrf: Fix fast path output packet handling with async Netfilter
rules"
* tag 'net-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (65 commits)
lan743x: fix use of uninitialized variable
net: udp: fix IP header access and skb lookup on Fast/frag0 UDP GRO
net: udp: fix UDP header access on Fast/frag0 UDP GRO
devlink: Avoid overwriting port attributes of registered port
vrf: Fix fast path output packet handling with async Netfilter rules
cosa: Add missing kfree in error path of cosa_write
net: switch to the kernel.org patchwork instance
ch_ktls: stop the txq if reaches threshold
ch_ktls: tcb update fails sometimes
ch_ktls/cxgb4: handle partial tag alone SKBs
ch_ktls: don't free skb before sending FIN
ch_ktls: packet handling prior to start marker
ch_ktls: Correction in middle record handling
ch_ktls: missing handling of header alone
ch_ktls: Correction in trimmed_len calculation
cxgb4/ch_ktls: creating skbs causes panic
ch_ktls: Update cheksum information
ch_ktls: Correction in finding correct length
cxgb4/ch_ktls: decrypted bit is not enough
net/x25: Fix null-ptr-deref in x25_connect
...
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"Make the intel_pstate driver behave as expected when it operates in
the passive mode with HWP enabled and the 'powersave' governor on top
of it"
* tag 'pm-5.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: intel_pstate: Take CPUFREQ_GOV_STRICT_TARGET into account
cpufreq: Add strict_target to struct cpufreq_policy
cpufreq: Introduce CPUFREQ_GOV_STRICT_TARGET
cpufreq: Introduce governor flags
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In bpf_pid_task_storage_update_elem(), it missed to
test the !task_storage_ptr(task) which then could trigger a NULL
pointer exception in bpf_local_storage_update().
Fixes: 4cf1bc1f1045 ("bpf: Implement task local storage")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: Roman Gushchin <guro@fb.com>
Acked-by: KP Singh <kpsingh@google.com>
Link: https://lore.kernel.org/bpf/20201112001919.2028357-1-kafai@fb.com
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git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb
Pull swiotlb fixes from Konrad Rzeszutek Wilk:
"Two tiny fixes for issues that make drivers under Xen unhappy under
certain conditions"
* 'stable/for-linus-5.10-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: remove the tbl_dma_addr argument to swiotlb_tbl_map_single
swiotlb: fix "x86: Don't panic if can not alloc buffer for swiotlb"
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A bunch of functions in the new ringbuffer code take both a
printk_ringbuffer struct and a separate prb_data_ring. This is a relic
from an earlier version of the code when a second data ring was present.
Since this is no longer the case remove the extra function argument
from:
- data_make_reusable()
- data_push_tail()
- data_alloc()
- data_realloc()
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
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The unsigned variable datasec_id is assigned a return value from the call
to check_pseudo_btf_id(), which may return negative error code.
This fixes the following coccicheck warning:
./kernel/bpf/verifier.c:9616:5-15: WARNING: Unsigned expression compared with zero: datasec_id > 0
Fixes: eaa6bcb71ef6 ("bpf: Introduce bpf_per_cpu_ptr()")
Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Cc: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/bpf/1605071026-25906-1-git-send-email-kaixuxia@tencent.com
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Make sure btf_parse_module() is compiled out if module BTFs are not enabled.
Fixes: 36e68442d1af ("bpf: Load and verify kernel module BTFs")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201111040645.903494-1-andrii@kernel.org
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s/detetector/detector/
s/enfoced/enforced/
s/writen/written/
s/actualy/actually/
s/bascially/basically/
s/Regarldess/Regardless/
s/zeroes/zeros/
s/followd/followed/
s/incrememented/incremented/
s/separatelly/separately/
s/accesible/accessible/
s/sythetic/synthetic/
s/enabed/enabled/
s/heurisitc/heuristic/
s/assocated/associated/
s/otherwides/otherwise/
s/specfied/specified/
s/seaching/searching/
s/hierachry/hierarchy/
s/internel/internal/
s/Thise/This/
Link: https://lkml.kernel.org/r/20201029150554.3354-1-hqjagain@gmail.com
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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'ret' in 2 functions are not used. and one of them is a void function.
So remove them to avoid gcc warning:
kernel/trace/ftrace.c:4166:6: warning: variable ‘ret’ set but not used
[-Wunused-but-set-variable]
kernel/trace/ftrace.c:5571:6: warning: variable ‘ret’ set but not used
[-Wunused-but-set-variable]
Link: https://lkml.kernel.org/r/1604674486-52350-1-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Add a new config RING_BUFFER_RECORD_RECURSION that will place functions that
recurse from the ring buffer into the ftrace recused_functions file.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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Inspecting the data structures of the function graph tracer, I found that
the overrun value is unsigned long, which is 8 bytes on a 64 bit machine,
and not only that, the depth is an int (4 bytes). The overrun can be simply
an unsigned int (4 bytes) and pack the ftrace_graph_ret structure better.
The depth is moved up next to the func, as it is used more often with func,
and improves cache locality.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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The try_invoke_on_locked_down_task() function requires that
interrupts be enabled, but it is called with interrupts disabled from
rcu_print_task_stall(), resulting in an "IRQs not enabled as expected"
diagnostic. This commit therefore updates rcu_print_task_stall()
to accumulate a list of the first few tasks while holding the current
leaf rcu_node structure's ->lock, then releases that lock and only then
uses try_invoke_on_locked_down_task() to attempt to obtain per-task
detailed information. Of course, as soon as ->lock is released, the
task might exit, so the get_task_struct() function is used to prevent
the task structure from going away in the meantime.
Link: https://lore.kernel.org/lkml/000000000000903d5805ab908fc4@google.com/
Fixes: 5bef8da66a9c ("rcu: Add per-task state to RCU CPU stall warnings")
Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com
Reported-by: syzbot+f04854e1c5c9e913cc27@syzkaller.appspotmail.com
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
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Add kernel module listener that will load/validate and unload module BTF.
Module BTFs gets ID generated for them, which makes it possible to iterate
them with existing BTF iteration API. They are given their respective module's
names, which will get reported through GET_OBJ_INFO API. They are also marked
as in-kernel BTFs for tooling to distinguish them from user-provided BTFs.
Also, similarly to vmlinux BTF, kernel module BTFs are exposed through
sysfs as /sys/kernel/btf/<module-name>. This is convenient for user-space
tools to inspect module BTF contents and dump their types with existing tools:
[vmuser@archvm bpf]$ ls -la /sys/kernel/btf
total 0
drwxr-xr-x 2 root root 0 Nov 4 19:46 .
drwxr-xr-x 13 root root 0 Nov 4 19:46 ..
...
-r--r--r-- 1 root root 888 Nov 4 19:46 irqbypass
-r--r--r-- 1 root root 100225 Nov 4 19:46 kvm
-r--r--r-- 1 root root 35401 Nov 4 19:46 kvm_intel
-r--r--r-- 1 root root 120 Nov 4 19:46 pcspkr
-r--r--r-- 1 root root 399 Nov 4 19:46 serio_raw
-r--r--r-- 1 root root 4094095 Nov 4 19:46 vmlinux
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-5-andrii@kernel.org
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Allocate ID for vmlinux BTF. This makes it visible when iterating over all BTF
objects in the system. To allow distinguishing vmlinux BTF (and later kernel
module BTF) from user-provided BTFs, expose extra kernel_btf flag, as well as
BTF name ("vmlinux" for vmlinux BTF, will equal to module's name for module
BTF). We might want to later allow specifying BTF name for user-provided BTFs
as well, if that makes sense. But currently this is reserved only for
in-kernel BTFs.
Having in-kernel BTFs exposed IDs will allow to extend BPF APIs that require
in-kernel BTF type with ability to specify BTF types from kernel modules, not
just vmlinux BTF. This will be implemented in a follow up patch set for
fentry/fexit/fmod_ret/lsm/etc.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-3-andrii@kernel.org
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Adjust in-kernel BTF implementation to support a split BTF mode of operation.
Changes are mostly mirroring libbpf split BTF changes, with the exception of
start_id being 0 for in-kernel implementation due to simpler read-only mode.
Otherwise, for split BTF logic, most of the logic of jumping to base BTF,
where necessary, is encapsulated in few helper functions. Type numbering and
string offset in a split BTF are logically continuing where base BTF ends, so
most of the high-level logic is kept without changes.
Type verification and size resolution is only doing an added resolution of new
split BTF types and relies on already cached size and type resolution results
in the base BTF.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20201110011932.3201430-2-andrii@kernel.org
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The Energy Model supports power values expressed in milli-Watts or in an
'abstract scale'. Update the related comments is the code to reflect that
state.
Reviewed-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There are different platforms and devices which might use different scale
for the power values. Kernel sub-systems might need to check if all
Energy Model (EM) devices are using the same scale. Address that issue and
store the information inside EM for each device. Thanks to that they can
be easily compared and proper action triggered.
Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Pull core dump fix from Al Viro:
"Fix for multithreaded coredump playing fast and loose with getting
registers of secondary threads; if a secondary gets caught in the
middle of exit(2), the conditition it will be stopped in for dumper to
examine might be unusual enough for things to go wrong.
Quite a few architectures are fine with that, but some are not."
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
don't dump the threads that had been already exiting when zapped.
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After reboot, it's not possible to use hotkeys to enter BIOS setup
and boot menu on some HP laptops.
BIOS folks identified the root cause is the missing _PTS call, and
BIOS is expecting _PTS to do proper reset.
Using S5 for reboot is default behavior under Windows, "A full
shutdown (S5) occurs when a system restart is requested" [1], so
let's do the same here.
[1] https://docs.microsoft.com/en-us/windows/win32/power/system-power-states
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The CFS wakeup code will only ever go through EAS / its fast path on
"regular" wakeups (i.e. not on forks or execs). These are currently gated
by a check against 'sd_flag', which would be SD_BALANCE_WAKE at wakeup.
However, we now have a flag that explicitly tells us whether a wakeup is a
"regular" one, so hinge those conditions on that flag instead.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201102184514.2733-4-valentin.schneider@arm.com
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Only select_task_rq_fair() uses that parameter to do an actual domain
search, other classes only care about what kind of wakeup is happening
(fork, exec, or "regular") and thus just translate the flag into a wakeup
type.
WF_TTWU and WF_EXEC have just been added, use these along with WF_FORK to
encode the wakeup types we care about. For select_task_rq_fair(), we can
simply use the shiny new WF_flag : SD_flag mapping.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201102184514.2733-3-valentin.schneider@arm.com
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To remove the sd_flag parameter of select_task_rq(), we need another way of
encoding wakeup types. There already is a WF_FORK flag, add the missing two.
With that said, we still need an easy way to turn WF_foo into
SD_bar (e.g. WF_TTWU into SD_BALANCE_WAKE). As suggested by Peter, let's
make our lives easier and make them match exactly, and throw in some
compile-time checks for good measure.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201102184514.2733-2-valentin.schneider@arm.com
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Since ab93a4bc955b ("sched/fair: Remove distribute_running fromCFS
bandwidth"), there is nothing to protect between
raw_spin_lock_irqsave/store() in do_sched_cfs_slack_timer().
Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20201030144621.GA96974@rlk
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Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201013140116.26651-2-valentin.schneider@arm.com
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migrate_disable();
set_cpus_allowed_ptr(current, {something excluding task_cpu(current)});
affine_move_task(); <-- never returns
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201013140116.26651-1-valentin.schneider@arm.com
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In order to minimize the interference of migrate_disable() on lower
priority tasks, which can be deprived of runtime due to being stuck
below a higher priority task. Teach the RT/DL balancers to push away
these higher priority tasks when a lower priority task gets selected
to run on a freshly demoted CPU (pull).
This adds migration interference to the higher priority task, but
restores bandwidth to system that would otherwise be irrevocably lost.
Without this it would be possible to have all tasks on the system
stuck on a single CPU, each task preempted in a migrate_disable()
section with a single high priority task running.
This way we can still approximate running the M highest priority tasks
on the system.
Migrating the top task away is (ofcourse) still subject to
migrate_disable() too, which means the lower task is subject to an
interference equivalent to the worst case migrate_disable() section.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.499155098@infradead.org
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There's a valid ->pi_lock recursion issue where the actual PI code
tries to wake up the stop task. Make lockdep aware so it doesn't
complain about this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.406912197@infradead.org
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We want migrate_disable() tasks to get PULLs in order for them to PUSH
away the higher priority task.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.310519774@infradead.org
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Replace a bunch of cpumask_any*() instances with
cpumask_any*_distribute(), by injecting this little bit of random in
cpu selection, we reduce the chance two competing balance operations
working off the same lowest_mask pick the same CPU.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.190759694@infradead.org
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On CPU unplug tasks which are in a migrate disabled region cannot be pushed
to a different CPU until they returned to migrateable state.
Account the number of tasks on a runqueue which are in a migrate disabled
section and make the hotplug wait mechanism respect that.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102347.067278757@infradead.org
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Concurrent migrate_disable() and set_cpus_allowed_ptr() has
interesting features. We rely on set_cpus_allowed_ptr() to not return
until the task runs inside the provided mask. This expectation is
exported to userspace.
This means that any set_cpus_allowed_ptr() caller must wait until
migrate_enable() allows migrations.
At the same time, we don't want migrate_enable() to schedule, due to
patterns like:
preempt_disable();
migrate_disable();
...
migrate_enable();
preempt_enable();
And:
raw_spin_lock(&B);
spin_unlock(&A);
this means that when migrate_enable() must restore the affinity
mask, it cannot wait for completion thereof. Luck will have it that
that is exactly the case where there is a pending
set_cpus_allowed_ptr(), so let that provide storage for the async stop
machine.
Much thanks to Valentin who used TLA+ most effective and found lots of
'interesting' cases.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.921768277@infradead.org
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Add the base migrate_disable() support (under protest).
While migrate_disable() is (currently) required for PREEMPT_RT, it is
also one of the biggest flaws in the system.
Notably this is just the base implementation, it is broken vs
sched_setaffinity() and hotplug, both solved in additional patches for
ease of review.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.818170844@infradead.org
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Thread a u32 flags word through the *set_cpus_allowed*() callchain.
This will allow adding behavioural tweaks for future users.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.729082820@infradead.org
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Since we now migrate tasks away before DYING, we should also move
bandwidth unthrottle, otherwise we can gain tasks from unthrottle
after we expect all tasks to be gone already.
Also; it looks like the RT balancers don't respect cpu_active() and
instead rely on rq->online in part, complete this. This too requires
we do set_rq_offline() earlier to match the cpu_active() semantics.
(The bigger patch is to convert RT to cpu_active() entirely)
Since set_rq_online() is called from sched_cpu_activate(), place
set_rq_offline() in sched_cpu_deactivate().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.639538965@infradead.org
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With the new mechanism which kicks tasks off the outgoing CPU at the end of
schedule() the situation on an outgoing CPU right before the stopper thread
brings it down completely is:
- All user tasks and all unbound kernel threads have either been migrated
away or are not running and the next wakeup will move them to a online CPU.
- All per CPU kernel threads, except cpu hotplug thread and the stopper
thread have either been unbound or parked by the responsible CPU hotplug
callback.
That means that at the last step before the stopper thread is invoked the
cpu hotplug thread is the last legitimate running task on the outgoing
CPU.
Add a final wait step right before the stopper thread is kicked which
ensures that any still running tasks on the way to park or on the way to
kick themself of the CPU are either sleeping or gone.
This allows to remove the migrate_tasks() crutch in sched_cpu_dying(). If
sched_cpu_dying() detects that there is still another running task aside of
the stopper thread then it will explode with the appropriate fireworks.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.547163969@infradead.org
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Don't rely on the scheduler to force break affinity for us -- it will
stop doing that for per-cpu-kthreads.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.464718669@infradead.org
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RT kernels need to ensure that all tasks which are not per CPU kthreads
have left the outgoing CPU to guarantee that no tasks are force migrated
within a migrate disabled section.
There is also some desire to (ab)use fine grained CPU hotplug control to
clear a CPU from active state to force migrate tasks which are not per CPU
kthreads away for power control purposes.
Add a mechanism which waits until all tasks which should leave the CPU
after the CPU active flag is cleared have moved to a different online CPU.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.377836842@infradead.org
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In preparation for migrate_disable(), make sure only per-cpu kthreads
are allowed to run on !active CPUs.
This is ran (as one of the very first steps) from the cpu-hotplug
task which is a per-cpu kthread and completion of the hotplug
operation only requires such tasks.
This constraint enables the migrate_disable() implementation to wait
for completion of all migrate_disable regions on this CPU at hotplug
time without fear of any new ones starting.
This replaces the unlikely(rq->balance_callbacks) test at the tail of
context_switch with an unlikely(rq->balance_work), the fast path is
not affected.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.292709163@infradead.org
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The intent of balance_callback() has always been to delay executing
balancing operations until the end of the current rq->lock section.
This is because balance operations must often drop rq->lock, and that
isn't safe in general.
However, as noted by Scott, there were a few holes in that scheme;
balance_callback() was called after rq->lock was dropped, which means
another CPU can interleave and touch the callback list.
Rework code to call the balance callbacks before dropping rq->lock
where possible, and otherwise splice the balance list onto a local
stack.
This guarantees that the balance list must be empty when we take
rq->lock. IOW, we'll only ever run our own balance callbacks.
Reported-by: Scott Wood <swood@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Link: https://lkml.kernel.org/r/20201023102346.203901269@infradead.org
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