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Filename Latest commit message Latest commit date
Peng Liu 35975f2e83 sched/deadline: Fix sched_dl_global_validate()
[ Upstream commit a57415f5d1e43c3a5c5d412cd85e2792d7ed9b11 ]

When change sched_rt_{runtime, period}_us, we validate that the new
settings should at least accommodate the currently allocated -dl
bandwidth:

  sched_rt_handler()
    -->	sched_dl_bandwidth_validate()
	{
		new_bw = global_rt_runtime()/global_rt_period();

		for_each_possible_cpu(cpu) {
			dl_b = dl_bw_of(cpu);
			if (new_bw < dl_b->total_bw)    <-------
				ret = -EBUSY;
		}
	}

But under CONFIG_SMP, dl_bw is per root domain , but not per CPU,
dl_b->total_bw is the allocated bandwidth of the whole root domain.
Instead, we should compare dl_b->total_bw against "cpus*new_bw",
where 'cpus' is the number of CPUs of the root domain.

Also, below annotation(in kernel/sched/sched.h) implied implementation
only appeared in SCHED_DEADLINE v2[1], then deadline scheduler kept
evolving till got merged(v9), but the annotation remains unchanged,
meaningless and misleading, update it.

* With respect to SMP, the bandwidth is given on a per-CPU basis,
* meaning that:
*  - dl_bw (< 100%) is the bandwidth of the system (group) on each CPU;
*  - dl_total_bw array contains, in the i-eth element, the currently
*    allocated bandwidth on the i-eth CPU.

[1]: https://lore.kernel.org/lkml/1267385230.13676.101.camel@Palantir/

Fixes: 332ac17ef5 ("sched/deadline: Add bandwidth management for SCHED_DEADLINE tasks")
Signed-off-by: Peng Liu <iwtbavbm@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/db6bbda316048cda7a1bbc9571defde193a8d67e.1602171061.git.iwtbavbm@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-30 11:51:03 +01:00
arch x86/apic: Fix x2apic enablement without interrupt remapping 2020-12-30 11:51:03 +01:00
block blk-mq: In blk_mq_dispatch_rq_list() "no budget" is a reason to kick 2020-12-30 11:50:54 +01:00
certs
crypto crypto: af_alg - avoid undefined behavior accessing salg_name 2020-12-30 11:51:00 +01:00
Documentation KVM: mmu: Fix SPTE encoding of MMIO generation upper half 2020-12-21 13:27:06 +01:00
drivers RDMA/rxe: Compute PSN windows correctly 2020-12-30 11:51:02 +01:00
fs quota: Sanity-check quota file headers on load 2020-12-30 11:51:00 +01:00
include crypto: af_alg - avoid undefined behavior accessing salg_name 2020-12-30 11:51:00 +01:00
init printk: reduce LOG_BUF_SHIFT range for H8300 2020-11-05 11:43:16 +01:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel sched/deadline: Fix sched_dl_global_validate() 2020-12-30 11:51:03 +01:00
lib lib/syscall: fix syscall registers retrieval on 32-bit platforms 2020-12-11 13:23:32 +01:00
LICENSES
mm mm/zsmalloc.c: drop ZSMALLOC_PGTABLE_MAPPING 2020-12-16 10:56:59 +01:00
net Bluetooth: Fix slab-out-of-bounds read in hci_le_direct_adv_report_evt() 2020-12-30 11:51:00 +01:00
samples samples/bpf: Fix possible deadlock in xdpsock 2020-11-05 11:43:17 +01:00
scripts kbuild: avoid split lines in .mod files 2020-12-30 11:50:57 +01:00
security selinux: fix error initialization in inode_doinit_with_dentry() 2020-12-30 11:51:02 +01:00
sound ALSA: pcm: oss: Fix potential out-of-bounds shift 2020-12-21 13:27:06 +01:00
tools selftests: fix poll error in udpgro.sh 2020-12-30 11:50:56 +01:00
usr
virt KVM: arm64: vgic-v3: Drop the reporting of GICR_TYPER.Last for userspace 2020-12-02 08:49:46 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.85 2020-12-21 13:27:07 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.