Sync to vmlinux.h from sched_ext/for-6.11 1edab907b57d ("sched_ext/scx_qmap:
Pick idle CPU for direct dispatch on !wakeup enqueues"). This most likely
will be the commit which will be merged during the upcoming kernel v6.11
merge window.
Unfortunately, this is a compatibility breaking change. As the size of
bpf_iter_scx_dsq is reduced, schedulers that use the iterator - scx_lavd and
scx_layered - won't be able to run on older kernels. Likewise, older
binaries from before this commit won't be able to run on newer kernels.
Sync from sched_ext/for-6.11 1edab907b57d ("sched_ext/scx_qmap: Pick idle
CPU for direct dispatch on !wakeup enqueues")
git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git for-6.11
- cgroup support hasn't landed in the upstream kernel yet. This most likely
will happen in a few weeks. For the time being, disable scx_flatcg,
scx_pair and scx_mitosis.
- Compat macro for DSQ task iterator dropped. This is now a part of
the baseline.
- scx_bpf_consume() isn't upstream yet. BPF interfacing side is still being
discussed. Dropped example usage from tools/sched_ext. None of the
practical schedulers use it, so this should be fine for now.
- scx_bpf_cpu_rq() added.
- AUTOATTACH workaround for newer libbpf versions added.
__COMPAT_scx_bpf_consume_task() wasn't calling scx_bpf_consume_task() at all
and was always returning false. Fix it.
Also, update scx_qmap usage example so that it matches cgroup ID rather than
comm prefix. This should make testing with multiple processes a bit easier.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop support for missing sched_ext_ops.dump*(). The
open helper macros now check the existence of the fields and abort if
missing.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop support for missing sched_ext_ops.tick(). The
open helper macros now check the existence of the field and abort if
missing.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop support for missing sched_ext_ops.exit_dump_len.
The open helper macros now check the existence of the field and abort if
missing.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop support for missing sched_ext_ops.hotplug_seq.
The open helper macros now check the existence of the field and abort if
missing.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_scx_bpf_cpuperf_*(). The open helper
macros now check the existence of scx_bpf_cpuperf_cap() and abort if not.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_HAS_CPUMASKS(). The open helper macros
now check the existence of scx_bpf_nr_cpu_ids() and abort if not.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_scx_bpf_dump(). The open helper macros
now check the existence of scx_bpf_dump_bstr() and abort if not.
While at it, reorder the min requirement checks so that newly added ones are
up top to make testing easier.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_scx_bpf_exit(). The open helper macros
now check the existence of scx_bpf_exit_bstr() and abort if not.
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_SCX_KICK_IDLE. The open helper macros
now check the existence of SCX_KICK_IDLE and abort if not.
There's no guarantee that errno is set or contains relevant information when
SCX_BUG() is invoked. This sometimes leads to "task failed successfully"
messages:
# ./scx_simple
../scheds/c/scx_simple.c:72 [scx panic]: Success
SCX_OPS_SWITCH_PARTIAL missing, kernel too old?
While not critical, it's not great. Let's update it so that errno is printed
in parentheses when non-zero and match the tag to the macro name so that
what's printed is the following:
# ./scx_simple
[SCX_BUG] ../scheds/c/scx_simple.c:72
SCX_OPS_SWITCH_PARTIAL missing, kernel too old?
In preparation of upstreaming, let's set the min version requirement at the
released v6.9 kernels. Drop __COMPAT_scx_bpf_switch_call(). The open helper
macros now check the existence of SCX_OPS_SWITCH_PARTIAL and abort if not.
The bpf_ prefix is used for BPF API. Rename bpf_log2() to u32_log2() and
bpf_log2l() to u64_log2(). While at it, relocate them below compiler
directive helpers.
These are used in mitosis, but they belong in common code so other
schedulers can do css iteration.
Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>
The RESIZE_ARRAY() macro assumes the presence of an in-scope "skel" variable.
This is bad practice and can cause issues in other macros that use it. Let's
update it to explicitly take a skel argument.
Signed-off-by: David Vernet <void@manifault.com>
In order to prevent compiler from merging or refetching load/store
operations or unwanted reordering, we take the implemetation of
READ_ONCE()/WRITE_ONCE() from kernel sources under
"/include/asm-generic/rwonce.h".
Use WRITE_ONCE() in function flip_sys_cpu_util() to ensure the compiler
doesn't perform unnecessary optimization so the compiler won't make
incorrect assumptions when performing the operation of modifying of bit
flipping.
Signed-off-by: I Hsin Cheng <richard120310@gmail.com>
scx_rustland has a function called get_cpu_owner() in BPF which
currently has no callers. There's nothing wrong with the function, but
it causes a warning due to an unused function. Let's just annotate it
with __maybe_unused to tell the compiler that it's not a problem.
Signed-off-by: David Vernet <void@manifault.com>
C SCX_OPS_ATTACH() and rust scx_ops_attach() macros were not calling
.attach() and were only attaching the struct_ops. This meant that all
non-struct_ops BPF programs contained in the skels were never attached which
breaks e.g. scx_layered.
Let's fix it by adding .attach() invocation the the attach macros.
We can hint to the compiler about paths we'll take in a scheduler. This
is a common pattern, so lets provide convenience macros.
Signed-off-by: David Vernet <void@manifault.com>
scx_lavd implemented 32 and 64 bit versions of a base-2 logarithm
function. This is now also used in rusty. To avoid code duplication,
let's pull it into a shared header.
Note that there is technically a functional change here as we remove the
always inline compiler directive. We instead assume that the compiler
will know best whether or not to inline the function.
Signed-off-by: David Vernet <void@manifault.com>
Only the very newest kernels support scx_bpf_cpuperf_set(). Let's update
scx_layered to accommodate older kernels as well.
Signed-off-by: David Vernet <void@manifault.com>
This change adds `scx_bpf_cpuperf_cap`, `scx_bpf_cpuperf_cur` and
`scx_bpf_cpuperf_set` definitions that were recently introduced into
[`sched_ext`](https://github.com/sched-ext/sched_ext/pull/180). It adds
a `perf` field to `scx_layered` to allow for controlling performance per
layer.
Signed-off-by: Daniel Hodges <hodges.daniel.scott@gmail.com>
The scx_rusty scheduler does not support hotplug, and expects a static
host topology throughout its runtime. Though the kernel does have
support for detecting hotplug events, we currently don't detect this in
the kernel, nor surface it to user space when it happens. Now that we
have scx_bpf_exit(), we can gracefully exit the kernel in the event of a
hotplug, and communicate to user space that it should restart the
scheduler.
This patch adds that support to scx_rusty. Note that this assumes that
we're running on a recent enough kernel that has scx_bpf_exit(). If it
doesn't, then we instead just error out of the kernel scheduler and exit
the application.
Signed-off-by: David Vernet <void@manifault.com>
Synchronize stragglers.
- Bug fix in __COMPAT_read_enum().
- A cosmetic difference in scx_qmap.bpf.c.
- Stray 'p' when calling getopt() in scx_simple.c.
After this the kernel tree and scx repo are in sync.
Sync from kernel to receive new vmlinux.h and the updates to common headers.
This includes the following updates:
- scx_bpf_switch_all() is replaced by SCX_OPS_SWITCH_PARTIAL flag.
- sched_ext_ops.exit_dump_len added to allow customizing dump buffer size.
- scx_bpf_exit() added.
- Common headers updated to provide backward compatibility in a way which
hides most complexities from scheduler implementations.
scx_simple, qmap, central and flatcg are updated accordingly. Other
schedulers are broken for the moment.
The flatcg scheduler uses a rb_node type - struct cgv_node - to keep
track of vtime. On cgroup init, a cgv_node is created and stashed in a
hashmap - cgv_node_stash - for later use. In cgroup_enqueued and
try_pick_next_cgroup, the node is inserted into the rbtree, which
required removing it from the stash before this patch's changes.
This patch makes cgv_node refcounted, which allows keeping it in the
stash for the entirety of the cgroup's lifetime. Unnecessary
bpf_kptr_xchg's and other boilerplate can be removed as a result.
Note that in addition to bpf_refcount patches, which have been upstream
for quite some time, this change depends on a more recent series [0].
[0]: https://lore.kernel.org/bpf/20231107085639.3016113-1-davemarchevsky@fb.com/
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
SCX_KICK_IDLE is a new feature which isn't defined in older kernels. Add
compat wrapper and use it for idle CPU wakeups.
Signed-off-by: Tejun Heo <tj@kernel.org>
26ae1b0356
changed scx_exit_info which requires us to rebuild with a new vmlinux.h
This patch updates vmlinux.h to the current sched_ext branch in the
github repo.
Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>
In the latest kernel, sched_ext API has changed in two areas:
- ops.prep_enable/cancel_enable/enable/disable() replaced with
ops.init_task/enable/disable/exit_task().
- scx_bpf_dispatch() can now be called from ops.select_cpu(). Also,
SCX_ENQ_LOCAL flag is removed. Instead, users can call
scx_bpf_select_cpu_dfl() from ops.select_cpu() and use the @is_idle out
param value to determine whether to dispatch directly.
This commit updates all schedules so that they build.
- Init functions renamed / merged / split.
- ops.select_cpu() is added to several schedulers and local direct
disptching logic is moved there.
This is the minimum update which is need to make the schedulers build and
work. It needs further update to e.g. move vtime udpates to ops.enable().
Improve build portability by including asm-generic/errno.h, instead of
linux/errno.h.
The difference between these two headers can be summarized as following:
- asm-generic/errno.h contains generic error code definitions that are
intended to be common across different architectures,
- linux/errno.h includes architecture-specific error codes and
provides additional (or overrides) error code definitions based on
the specific architecture where the code is compiled.
Considering the architecture-independent nature of scx, the advantages
of being able to use architecture-specific error codes are marginal or
negligible (and we should probably discourage using them).
Moving towards asm-generic/errno.h, however, allows the removal of
cross-compilation dependencies (such as the gcc-multilib package in
Debian/Ubuntu) and improves the code portability across various
architectures and distributions.
This also allows to remove a symlink hack from the github workflow.
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
