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Will be used by 'perf trace' to support 'perf trace --filter', we need
to append to any pre-existing filter.
When parse_filter() gets invoked to process --filter, it'll set the
filter to that specified on the command line, later on, when we filter
out 'perf trace' own pid to avoid an event feedback loop, we need to
preserve the command line filter put in place by parse_filter().
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Will be used to append such lists to existing filters.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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So that we can go from:
# perf trace -e msr:write_msr --max-stack=16 sleep 1
0.000 sleep/6740 msr:write_msr(msr: 3221225728, val: 139636317451648)
do_trace_write_msr ([kernel.kallsyms])
do_trace_write_msr ([kernel.kallsyms])
do_arch_prctl_64 ([kernel.kallsyms])
__x64_sys_arch_prctl ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
entry_SYSCALL_64 ([kernel.kallsyms])
init_tls (/usr/lib64/ld-2.29.so)
dl_main (/usr/lib64/ld-2.29.so)
_dl_sysdep_start (/usr/lib64/ld-2.29.so)
_dl_start (/usr/lib64/ld-2.29.so)
#
To:
# perf trace -e msr:write_msr --max-stack=16 sleep 1
0.000 sleep/8519 msr:write_msr(msr: FS_BASE, val: 139878031705472)
do_trace_write_msr ([kernel.kallsyms])
do_trace_write_msr ([kernel.kallsyms])
do_arch_prctl_64 ([kernel.kallsyms])
__x64_sys_arch_prctl ([kernel.kallsyms])
do_syscall_64 ([kernel.kallsyms])
entry_SYSCALL_64 ([kernel.kallsyms])
init_tls (/usr/lib64/ld-2.29.so)
dl_main (/usr/lib64/ld-2.29.so)
_dl_sysdep_start (/usr/lib64/ld-2.29.so)
_dl_start (/usr/lib64/ld-2.29.so)
#
This, in reverse, will allow for symbolic system call/tracepoint
filtering.
Cc: Adrian Hunter <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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We need to wrap those autogenerated string arrays with the
strarrays__scnprintf() formatter, do it.
Cc: Adrian Hunter <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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For instance 'msr' appears in several tracepoints, so we can associate
it with a single scnprintf() routine auto-generated from kernel headers,
as will be done in followup patches.
Start with an empty array of associations.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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This way we generate the source with the table for later use by plugins,
etc.
I.e. after running:
$ make -C tools/perf O=/tmp/build/perf
We end up with:
$ head /tmp/build/perf/trace/beauty/generated/x86_arch_MSRs_array.c
static const char *x86_MSRs[] = {
[0x00000000] = "IA32_P5_MC_ADDR",
[0x00000001] = "IA32_P5_MC_TYPE",
[0x00000010] = "IA32_TSC",
[0x00000017] = "IA32_PLATFORM_ID",
[0x0000001b] = "IA32_APICBASE",
[0x00000020] = "KNC_PERFCTR0",
[0x00000021] = "KNC_PERFCTR1",
[0x00000028] = "KNC_EVNTSEL0",
[0x00000029] = "KNC_EVNTSEL1",
$
Now its just a matter of using it, first in a libtracevent plugin.
At some point we should move tools/perf/trace/beauty to tools/beauty/,
so that it can be used more generally and even made available externally
like libbpf, libperf, libtraevent, etc.
Cc: Adrian Hunter <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Without parameters it'll parse tools/arch/x86/include/asm/msr-index.h
and output a table usable by tools, that will be wired up later to a
libtraceevent plugin registered from perf's glue code:
$ tools/perf/trace/beauty/tracepoints/x86_msr.sh
static const char *x86_MSRs[] = {
<SNIP>
[0x00000034] = "SMI_COUNT",
[0x0000003a] = "IA32_FEATURE_CONTROL",
[0x0000003b] = "IA32_TSC_ADJUST",
[0x00000040] = "LBR_CORE_FROM",
[0x00000048] = "IA32_SPEC_CTRL",
[0x00000049] = "IA32_PRED_CMD",
<SNIP>
[0x0000010b] = "IA32_FLUSH_CMD",
[0x0000010F] = "TSX_FORCE_ABORT",
<SNIP>
[0x00000198] = "IA32_PERF_STATUS",
[0x00000199] = "IA32_PERF_CTL",
<SNIP>
[0x00000da0] = "IA32_XSS",
[0x00000dc0] = "LBR_INFO_0",
[0x00000ffc] = "IA32_BNDCFGS_RSVD",
};
#define x86_64_specific_MSRs_offset 0xc0000080
static const char *x86_64_specific_MSRs[] = {
[0xc0000080 - x86_64_specific_MSRs_offset] = "EFER",
[0xc0000081 - x86_64_specific_MSRs_offset] = "STAR",
[0xc0000082 - x86_64_specific_MSRs_offset] = "LSTAR",
[0xc0000083 - x86_64_specific_MSRs_offset] = "CSTAR",
[0xc0000084 - x86_64_specific_MSRs_offset] = "SYSCALL_MASK",
<SNIP>
[0xc0000103 - x86_64_specific_MSRs_offset] = "TSC_AUX",
[0xc0000104 - x86_64_specific_MSRs_offset] = "AMD64_TSC_RATIO",
};
#define x86_AMD_V_KVM_MSRs_offset 0xc0010000
static const char *x86_AMD_V_KVM_MSRs[] = {
[0xc0010000 - x86_AMD_V_KVM_MSRs_offset] = "K7_EVNTSEL0",
<SNIP>
[0xc0010114 - x86_AMD_V_KVM_MSRs_offset] = "VM_CR",
[0xc0010115 - x86_AMD_V_KVM_MSRs_offset] = "VM_IGNNE",
[0xc0010117 - x86_AMD_V_KVM_MSRs_offset] = "VM_HSAVE_PA",
<SNIP>
[0xc0010240 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTL",
[0xc0010241 - x86_AMD_V_KVM_MSRs_offset] = "F15H_NB_PERF_CTR",
[0xc0010280 - x86_AMD_V_KVM_MSRs_offset] = "F15H_PTSC",
};
Then these will in turn be hooked up in a follow up patch to be used by
strarrays__scnprintf().
Cc: Adrian Hunter <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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We need it for things like MSRs that are sparse and go over MAXINT.
Cc: Adrian Hunter <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Luis Cláudio Gonçalves <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: https://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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It turns out that the NMI latency workaround from commit:
6d3edaae16c6 ("x86/perf/amd: Resolve NMI latency issues for active PMCs")
ends up being too conservative and results in the perf NMI handler claiming
NMIs too easily on AMD hardware when the NMI watchdog is active.
This has an impact, for example, on the hpwdt (HPE watchdog timer) module.
This module can produce an NMI that is used to reset the system. It
registers an NMI handler for the NMI_UNKNOWN type and relies on the fact
that nothing has claimed an NMI so that its handler will be invoked when
the watchdog device produces an NMI. After the referenced commit, the
hpwdt module is unable to process its generated NMI if the NMI watchdog is
active, because the current NMI latency mitigation results in the NMI
being claimed by the perf NMI handler.
Update the AMD perf NMI latency mitigation workaround to, instead, use a
window of time. Whenever a PMC is handled in the perf NMI handler, set a
timestamp which will act as a perf NMI window. Any NMIs arriving within
that window will be claimed by perf. Anything outside that window will
not be claimed by perf. The value for the NMI window is set to 100 msecs.
This is a conservative value that easily covers any NMI latency in the
hardware. While this still results in a window in which the hpwdt module
will not receive its NMI, the window is now much, much smaller.
Signed-off-by: Tom Lendacky <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Jerry Hoemann <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 6d3edaae16c6 ("x86/perf/amd: Resolve NMI latency issues for active PMCs")
Link: https://lkml.kernel.org/r/Message-ID:
Signed-off-by: Ingo Molnar <[email protected]>
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In perf_rotate_context(), when the first cpu flexible event fail to
schedule, cpu_rotate is 1, while cpu_event is NULL. Since cpu_event is
NULL, perf_rotate_context will _NOT_ call cpu_ctx_sched_out(), thus
cpuctx->ctx.is_active will have EVENT_FLEXIBLE set. Then, the next
perf_event_sched_in() will skip all cpu flexible events because of the
EVENT_FLEXIBLE bit.
In the next call of perf_rotate_context(), cpu_rotate stays 1, and
cpu_event stays NULL, so this process repeats. The end result is, flexible
events on this cpu will not be scheduled (until another event being added
to the cpuctx).
Here is an easy repro of this issue. On Intel CPUs, where ref-cycles
could only use one counter, run one pinned event for ref-cycles, one
flexible event for ref-cycles, and one flexible event for cycles. The
flexible ref-cycles is never scheduled, which is expected. However,
because of this issue, the cycles event is never scheduled either.
$ perf stat -e ref-cycles:D,ref-cycles,cycles -C 5 -I 1000
time counts unit events
1.000152973 15,412,480 ref-cycles:D
1.000152973 <not counted> ref-cycles (0.00%)
1.000152973 <not counted> cycles (0.00%)
2.000486957 18,263,120 ref-cycles:D
2.000486957 <not counted> ref-cycles (0.00%)
2.000486957 <not counted> cycles (0.00%)
To fix this, when the flexible_active list is empty, try rotate the
first event in the flexible_groups. Also, rename ctx_first_active() to
ctx_event_to_rotate(), which is more accurate.
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 8d5bce0c37fa ("perf/core: Optimize perf_rotate_context() event scheduling")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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perf_mmap() always increases user->locked_vm. As a result, "extra" could
grow bigger than "user_extra", which doesn't make sense. Here is an
example case:
(Note: Assume "user_lock_limit" is very small.)
| # of perf_mmap calls |vma->vm_mm->pinned_vm|user->locked_vm|
| 0 | 0 | 0 |
| 1 | user_extra | user_extra |
| 2 | 3 * user_extra | 2 * user_extra|
| 3 | 6 * user_extra | 3 * user_extra|
| 4 | 10 * user_extra | 4 * user_extra|
Fix this by maintaining proper user_extra and extra.
Reviewed-By: Hechao Li <[email protected]>
Reported-by: Hechao Li <[email protected]>
Signed-off-by: Song Liu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: <[email protected]>
Cc: Jie Meng <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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vtime_account_system() assumes that the target task to account cputime
to is always the current task. This is most often true indeed except on
task switch where we call:
vtime_common_task_switch(prev)
vtime_account_system(prev)
Here prev is the scheduling-out task where we account the cputime to. It
doesn't match current that is already the scheduling-in task at this
stage of the context switch.
So we end up checking the wrong task flags to determine if we are
accounting guest or system time to the previous task.
As a result the wrong task is used to check if the target is running in
guest mode. We may then spuriously account or leak either system or
guest time on task switch.
Fix this assumption and also turn vtime_guest_enter/exit() to use the
task passed in parameter as well to avoid future similar issues.
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wanpeng Li <[email protected]>
Fixes: 2a42eb9594a1 ("sched/cputime: Accumulate vtime on top of nsec clocksource")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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ratio precision
The quota/period ratio is used to ensure a child task group won't get
more bandwidth than the parent task group, and is calculated as:
normalized_cfs_quota() = [(quota_us << 20) / period_us]
If the quota/period ratio was changed during this scaling due to
precision loss, it will cause inconsistency between parent and child
task groups.
See below example:
A userspace container manager (kubelet) does three operations:
1) Create a parent cgroup, set quota to 1,000us and period to 10,000us.
2) Create a few children cgroups.
3) Set quota to 1,000us and period to 10,000us on a child cgroup.
These operations are expected to succeed. However, if the scaling of
147/128 happens before step 3, quota and period of the parent cgroup
will be changed:
new_quota: 1148437ns, 1148us
new_period: 11484375ns, 11484us
And when step 3 comes in, the ratio of the child cgroup will be
104857, which will be larger than the parent cgroup ratio (104821),
and will fail.
Scaling them by a factor of 2 will fix the problem.
Tested-by: Phil Auld <[email protected]>
Signed-off-by: Xuewei Zhang <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Phil Auld <[email protected]>
Cc: Anton Blanchard <[email protected]>
Cc: Ben Segall <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vincent Guittot <[email protected]>
Fixes: 2e8e19226398 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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kvmhv_switch_to_host() in arch/powerpc/kvm/book3s_hv_rmhandlers.S
needs to set kvmppc_vcore->in_guest to 0 to signal secondary CPUs to
continue. This happens after resetting the PCR. Before commit
13c7bb3c57dc ("powerpc/64s: Set reserved PCR bits"), r0 would always
be 0 before it was stored to kvmppc_vcore->in_guest. However because
of this change in the commit:
/* Reset PCR */
ld r0, VCORE_PCR(r5)
- cmpdi r0, 0
+ LOAD_REG_IMMEDIATE(r6, PCR_MASK)
+ cmpld r0, r6
beq 18f
- li r0, 0
- mtspr SPRN_PCR, r0
+ mtspr SPRN_PCR, r6
18:
/* Signal secondary CPUs to continue */
stb r0,VCORE_IN_GUEST(r5)
We are no longer comparing r0 against 0 and loading it with 0 if it
contains something else. Hence when we store r0 to
kvmppc_vcore->in_guest, it might not be 0. This means that secondary
CPUs will not be signalled to continue. Those CPUs get stuck and
errors like the following are logged:
KVM: CPU 1 seems to be stuck
KVM: CPU 2 seems to be stuck
KVM: CPU 3 seems to be stuck
KVM: CPU 4 seems to be stuck
KVM: CPU 5 seems to be stuck
KVM: CPU 6 seems to be stuck
KVM: CPU 7 seems to be stuck
This can be reproduced with:
$ for i in `seq 1 7` ; do chcpu -d $i ; done ;
$ taskset -c 0 qemu-system-ppc64 -smp 8,threads=8 \
-M pseries,accel=kvm,kvm-type=HV -m 1G -nographic -vga none \
-kernel vmlinux -initrd initrd.cpio.xz
Fix by making sure r0 is 0 before storing it to
kvmppc_vcore->in_guest.
Fixes: 13c7bb3c57dc ("powerpc/64s: Set reserved PCR bits")
Reported-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Jordan Niethe <[email protected]>
Reviewed-by: Alistair Popple <[email protected]>
Tested-by: Alexey Kardashevskiy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Newer versions of GCC (>= 9) demand that the size of the string to be
copied must be explicitly smaller than the size of the destination.
Thus, the NULL char has to be taken into account on strncpy.
This will avoid the following compiling error:
tlbie_test.c: In function 'main':
tlbie_test.c:639:4: error: 'strncpy' specified bound 100 equals destination size
strncpy(logdir, optarg, LOGDIR_NAME_SIZE);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Signed-off-by: Desnes A. Nunes do Rosario <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Since commit 1211ee61b4a8 ("powerpc/pseries: Read TLB Block Invalidate
Characteristics"), a warning message is displayed when booting a guest
on top of KVM:
lpar: arch/powerpc/platforms/pseries/lpar.c pseries_lpar_read_hblkrm_characteristics Error calling get-system-parameter (0xfffffffd)
This message is displayed because this hypervisor is not supporting
the H_BLOCK_REMOVE hcall and thus is not exposing the corresponding
feature.
Reading the TLB Block Invalidate Characteristics should not be done if
the feature is not exposed.
Fixes: 1211ee61b4a8 ("powerpc/pseries: Read TLB Block Invalidate Characteristics")
Reported-by: Stephen Rothwell <[email protected]>
Signed-off-by: Laurent Dufour <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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After merging the powerpc tree, today's linux-next build (powerpc64
allnoconfig) failed like this:
arch/powerpc/mm/book3s64/pgtable.c:216:3:
error: implicit declaration of function 'radix__flush_all_lpid_guest'
radix__flush_all_lpid_guest() is only declared for
CONFIG_PPC_RADIX_MMU which is not set for this build.
Fix it by adding an empty version for the RADIX_MMU=n case, which
should never be called.
Fixes: 99161de3a283 ("powerpc/64s/radix: tidy up TLB flushing code")
Signed-off-by: Stephen Rothwell <[email protected]>
[mpe: Munge change log]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Mark inode for force revalidation if LOOKUP_REVAL flag is set.
This tells the client to actually send a QueryInfo request to
the server to obtain the latest metadata in case a directory
or a file were changed remotely. Only do that if the client
doesn't have a lease for the file to avoid unneeded round
trips to the server.
Cc: <[email protected]>
Signed-off-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Steve French <[email protected]>
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Currently the client indicates that a dentry is stale when inode
numbers or type types between a local inode and a remote file
don't match. If this is the case attributes is not being copied
from remote to local, so, it is already known that the local copy
has stale metadata. That's why the inode needs to be marked for
revalidation in order to tell the VFS to lookup the dentry again
before openning a file. This prevents unexpected stale errors
to be returned to the user space when openning a file.
Cc: <[email protected]>
Signed-off-by: Pavel Shilovsky <[email protected]>
Signed-off-by: Steve French <[email protected]>
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Fixes: cb7a69e60590 ("cifs: Initialize filesystem timestamp ranges")
Only very old servers (e.g. OS/2 and DOS) did not support
DCE TIME (100 nanosecond granularity). Fix the checks used
to set minimum and maximum times.
Fixes xfstest generic/258 (on 5.4-rc1 and later)
CC: Deepa Dinamani <[email protected]>
Acked-by: Jeff Layton <[email protected]>
Signed-off-by: Steve French <[email protected]>
Reviewed-by: Pavel Shilovsky <[email protected]>
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Message was intended only for developer temporary build
In addition cleanup two minor warnings noticed by Coverity
and a trivial change to workaround a sparse warning
Signed-off-by: Steve French <[email protected]>
Reviewed-by: Pavel Shilovsky <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds
Pull LED fixes from Jacek Anaszewski:
- fix a leftover from earlier stage of development in the documentation
of recently added led_compose_name() and fix old mistake in the
documentation of led_set_brightness_sync() parameter name.
- MAINTAINERS: add pointer to Pavel Machek's linux-leds.git tree.
Pavel is going to take over LED tree maintainership from myself.
* tag 'led-fixes-for-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
Add my linux-leds branch to MAINTAINERS
leds: core: Fix leds.h structure documentation
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Add pointer to my git tree to MAINTAINERS. I'd like to maintain
linux-leds for-next branch for 5.5.
Signed-off-by: Pavel Machek <[email protected]>
Signed-off-by: Jacek Anaszewski <[email protected]>
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Update the leds.h structure documentation to define the
correct arguments.
Signed-off-by: Dan Murphy <[email protected]>
Signed-off-by: Jacek Anaszewski <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO fixes from Linus Walleij:
- don't clear FLAG_IS_OUT when emulating open drain/source in gpiolib
- fix up the usage of nonexclusive GPIO descriptors from device trees
- fix the incorrect IEC offset when toggling trigger edge in the
Spreadtrum driver
- use the correct unit for debounce settings in the MAX77620 driver
* tag 'gpio-v5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpio: max77620: Use correct unit for debounce times
gpio: eic: sprd: Fix the incorrect EIC offset when toggling
gpio: fix getting nonexclusive gpiods from DT
gpiolib: don't clear FLAG_IS_OUT when emulating open-drain/open-source
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git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinuxfix from Paul Moore:
"One patch to ensure we don't copy bad memory up into userspace"
* tag 'selinux-pr-20191007' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: fix context string corruption in convert_context()
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git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull Kselftest fixes from Shuah Khan:
"Fixes for existing tests and the framework.
Cristian Marussi's patches add the ability to skip targets (tests) and
exclude tests that didn't build from run-list. These patches improve
the Kselftest results. Ability to skip targets helps avoid running
tests that aren't supported in certain environments. As an example,
bpf tests from mainline aren't supported on stable kernels and have
dependency on bleeding edge llvm. Being able to skip bpf on systems
that can't meet this llvm dependency will be helpful.
Kselftest can be built and installed from the main Makefile. This
change help simplify Kselftest use-cases which addresses request from
users.
Kees Cook added per test timeout support to limit individual test
run-time"
* tag 'linux-kselftest-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
selftests: watchdog: Add command line option to show watchdog_info
selftests: watchdog: Validate optional file argument
selftests/kselftest/runner.sh: Add 45 second timeout per test
kselftest: exclude failed TARGETS from runlist
kselftest: add capability to skip chosen TARGETS
selftests: Add kselftest-all and kselftest-install targets
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Comet Lake is the new 10th Gen Intel processor. Add two new CPU model
numbers to the Intel family list.
The CPU model numbers are not published in the SDM yet but they come
from an authoritative internal source.
[ bp: Touch up commit message. ]
Signed-off-by: Kan Liang <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Tony Luck <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
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We discussed a better location for this file, and agreed that
core-api/ is a good fit. Rename it to symbol-namespaces.rst
for disambiguation, and also add it to index.rst and MAINTAINERS.
Signed-off-by: Masahiro Yamada <[email protected]>
Acked-by: Matthias Maennich <[email protected]>
Signed-off-by: Jessica Yu <[email protected]>
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There are no return value checking when using kzalloc() and kcalloc() for
memory allocation. so add it.
Signed-off-by: Yunfeng Ye <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
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With the use of the barrier implied by barrier_data(), there is no need
for memzero_explicit() to be extern. Making it inline saves the overhead
of a function call, and allows the code to be reused in arch/*/purgatory
without having to duplicate the implementation.
Tested-by: Hans de Goede <[email protected]>
Signed-off-by: Arvind Sankar <[email protected]>
Reviewed-by: Hans de Goede <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: H . Peter Anvin <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephan Mueller <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Fixes: 906a4bb97f5d ("crypto: sha256 - Use get/put_unaligned_be32 to get input, memzero_explicit")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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LLVM's assembler doesn't accept the short form INL instruction:
inl (%%dx)
but instead insists on the output register to be explicitly specified:
<inline asm>:1:7: error: invalid operand for instruction
inl (%dx)
^
LLVM ERROR: Error parsing inline asm
Use the full form of the instruction to fix the build.
Signed-off-by: Sami Tolvanen <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Acked-by: Thomas Hellstrom <[email protected]>
Cc: [email protected]
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: "VMware, Inc." <[email protected]>
Cc: x86-ml <[email protected]>
Link: https://github.com/ClangBuiltLinux/linux/issues/734
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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As per "AMD64 Architecture Programmer's Manual Volume 3: General-Purpose
and System Instructions", MWAITX EAX[7:4]+1 specifies the optional hint
of the optimized C-state. For C0 state, EAX[7:4] should be set to 0xf.
Currently, a value of 0xf is set for EAX[3:0] instead of EAX[7:4]. Fix
this by changing MWAITX_DISABLE_CSTATES from 0xf to 0xf0.
This hasn't had any implications so far because setting reserved bits in
EAX is simply ignored by the CPU.
[ bp: Fixup comment in delay_mwaitx() and massage. ]
Signed-off-by: Janakarajan Natarajan <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: "[email protected]" <[email protected]>
Cc: Zhenzhong Duan <[email protected]>
Cc: <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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GCC throws warning message as below:
‘clone_src_i_size’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
#define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0)
^
fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here
u64 clone_src_i_size;
^
The clone_src_i_size is only used as call-by-reference
in a call to get_inode_info().
Silence the warning by initializing clone_src_i_size to 0.
Note that the warning is a false positive and reported by older versions
of GCC (eg. 7.x) but not eg 9.x. As there have been numerous people, the
patch is applied. Setting clone_src_i_size to 0 does not otherwise make
sense and would not do any action in case the code changes in the future.
Signed-off-by: Austin Kim <[email protected]>
Reviewed-by: David Sterba <[email protected]>
[ add note ]
Signed-off-by: David Sterba <[email protected]>
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Currently the check for tbl_size being less than zero is always false
because tbl_size is unsigned. Fix this by making it a signed int.
Addresses-Coverity: ("Unsigned compared against 0")
Signed-off-by: Colin Ian King <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Jerry Snitselaar <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Fixes: e658c82be556 ("efi/tpm: Only set 'efi_tpm_final_log_size' after successful event log parsing")
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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The panel-tpo-td043mtea1 driver incorrectly includes the OF vendor
prefix in its SPI alias. Fix it, and move the manual alias to an SPI
module device table.
Fixes: dc2e1e5b2799 ("drm/panel: Add driver for the Toppoly TD043MTEA1 panel")
Reported-by: H. Nikolaus Schaller <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
Tested-by: H. Nikolaus Schaller <[email protected]>
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The panel-tpo-td028ttec1 driver incorrectly includes the OF vendor
prefix in its SPI alias. Fix it.
Fixes: 415b8dd08711 ("drm/panel: Add driver for the Toppoly TD028TTEC1 panel")
Reported-by: H. Nikolaus Schaller <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
Tested-by: H. Nikolaus Schaller <[email protected]>
Tested-by: Andreas Kemnade <[email protected]>
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The panel-sony-acx565akm driver incorrectly includes the OF vendor
prefix in its SPI alias. Fix it, and move the manual alias to an SPI
module device table.
Fixes: 1c8fc3f0c5d2 ("drm/panel: Add driver for the Sony ACX565AKM panel")
Reported-by: H. Nikolaus Schaller <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
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The panel-nec-nl8048hl11 driver incorrectly includes the OF vendor
prefix in its SPI alias. Fix it, and move the manual alias to an SPI
module device table.
Fixes: df439abe6501 ("drm/panel: Add driver for the NEC NL8048HL11 panel")
Reported-by: H. Nikolaus Schaller <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
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The panel-lg-lb035q02 driver incorrectly includes the OF vendor prefix
in its SPI alias. Fix it, and move the manual alias to an SPI module
device table.
Fixes: f5b0c6542476 ("drm/panel: Add driver for the LG Philips LB035Q02 panel")
Reported-by: H. Nikolaus Schaller <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>
Signed-off-by: Tomi Valkeinen <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Acked-by: Sam Ravnborg <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
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Any changes interesting to tasks waiting in io_cqring_wait() are
commited with io_cqring_ev_posted(). However, io_ring_drop_ctx_refs()
also tries to do that but with no reason, that means spurious wakeups
every io_free_req() and io_uring_enter().
Just use percpu_ref_put() instead.
Signed-off-by: Pavel Begunkov <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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Merge misc fixes from Andrew Morton:
"The usual shower of hotfixes.
Chris's memcg patches aren't actually fixes - they're mature but a few
niggling review issues were late to arrive.
The ocfs2 fixes are quite old - those took some time to get reviewer
attention.
Subsystems affected by this patch series: ocfs2, hotfixes, mm/memcg,
mm/slab-generic"
* emailed patches from Andrew Morton <[email protected]>:
mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two)
mm, sl[ou]b: improve memory accounting
mm, memcg: make scan aggression always exclude protection
mm, memcg: make memory.emin the baseline for utilisation determination
mm, memcg: proportional memory.{low,min} reclaim
mm/vmpressure.c: fix a signedness bug in vmpressure_register_event()
mm/page_alloc.c: fix a crash in free_pages_prepare()
mm/z3fold.c: claim page in the beginning of free
kernel/sysctl.c: do not override max_threads provided by userspace
memcg: only record foreign writebacks with dirty pages when memcg is not disabled
mm: fix -Wmissing-prototypes warnings
writeback: fix use-after-free in finish_writeback_work()
mm/memremap: drop unused SECTION_SIZE and SECTION_MASK
panic: ensure preemption is disabled during panic()
fs: ocfs2: fix a possible null-pointer dereference in ocfs2_info_scan_inode_alloc()
fs: ocfs2: fix a possible null-pointer dereference in ocfs2_write_end_nolock()
fs: ocfs2: fix possible null-pointer dereferences in ocfs2_xa_prepare_entry()
ocfs2: clear zero in unaligned direct IO
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|
In most configurations, kmalloc() happens to return naturally aligned
(i.e. aligned to the block size itself) blocks for power of two sizes.
That means some kmalloc() users might unknowingly rely on that
alignment, until stuff breaks when the kernel is built with e.g.
CONFIG_SLUB_DEBUG or CONFIG_SLOB, and blocks stop being aligned. Then
developers have to devise workaround such as own kmem caches with
specified alignment [1], which is not always practical, as recently
evidenced in [2].
The topic has been discussed at LSF/MM 2019 [3]. Adding a
'kmalloc_aligned()' variant would not help with code unknowingly relying
on the implicit alignment. For slab implementations it would either
require creating more kmalloc caches, or allocate a larger size and only
give back part of it. That would be wasteful, especially with a generic
alignment parameter (in contrast with a fixed alignment to size).
Ideally we should provide to mm users what they need without difficult
workarounds or own reimplementations, so let's make the kmalloc()
alignment to size explicitly guaranteed for power-of-two sizes under all
configurations. What this means for the three available allocators?
* SLAB object layout happens to be mostly unchanged by the patch. The
implicitly provided alignment could be compromised with
CONFIG_DEBUG_SLAB due to redzoning, however SLAB disables redzoning for
caches with alignment larger than unsigned long long. Practically on at
least x86 this includes kmalloc caches as they use cache line alignment,
which is larger than that. Still, this patch ensures alignment on all
arches and cache sizes.
* SLUB layout is also unchanged unless redzoning is enabled through
CONFIG_SLUB_DEBUG and boot parameter for the particular kmalloc cache.
With this patch, explicit alignment is guaranteed with redzoning as
well. This will result in more memory being wasted, but that should be
acceptable in a debugging scenario.
* SLOB has no implicit alignment so this patch adds it explicitly for
kmalloc(). The potential downside is increased fragmentation. While
pathological allocation scenarios are certainly possible, in my testing,
after booting a x86_64 kernel+userspace with virtme, around 16MB memory
was consumed by slab pages both before and after the patch, with
difference in the noise.
[1] https://lore.kernel.org/linux-btrfs/c3157c8e8e0e7588312b40c853f65c02fe6c957a.1566399731.git.christophe.leroy@c-s.fr/
[2] https://lore.kernel.org/linux-fsdevel/[email protected]/
[3] https://lwn.net/Articles/787740/
[[email protected]: documentation fixlet, per Matthew]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: Christoph Hellwig <[email protected]>
Cc: David Sterba <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Ming Lei <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: "Darrick J . Wong" <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Patch series "guarantee natural alignment for kmalloc()", v2.
This patch (of 2):
SLOB currently doesn't account its pages at all, so in /proc/meminfo the
Slab field shows zero. Modifying a counter on page allocation and
freeing should be acceptable even for the small system scenarios SLOB is
intended for. Since reclaimable caches are not separated in SLOB,
account everything as unreclaimable.
SLUB currently doesn't account kmalloc() and kmalloc_node() allocations
larger than order-1 page, that are passed directly to the page
allocator. As they also don't appear in /proc/slabinfo, it might look
like a memory leak. For consistency, account them as well. (SLAB
doesn't actually use page allocator directly, so no change there).
Ideally SLOB and SLUB would be handled in separate patches, but due to
the shared kmalloc_order() function and different kfree()
implementations, it's easier to patch both at once to prevent
inconsistencies.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vlastimil Babka <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Ming Lei <[email protected]>
Cc: Dave Chinner <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: "Darrick J . Wong" <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
This patch is an incremental improvement on the existing
memory.{low,min} relative reclaim work to base its scan pressure
calculations on how much protection is available compared to the current
usage, rather than how much the current usage is over some protection
threshold.
This change doesn't change the experience for the user in the normal
case too much. One benefit is that it replaces the (somewhat arbitrary)
100% cutoff with an indefinite slope, which makes it easier to ballpark
a memory.low value.
As well as this, the old methodology doesn't quite apply generically to
machines with varying amounts of physical memory. Let's say we have a
top level cgroup, workload.slice, and another top level cgroup,
system-management.slice. We want to roughly give 12G to
system-management.slice, so on a 32GB machine we set memory.low to 20GB
in workload.slice, and on a 64GB machine we set memory.low to 52GB.
However, because these are relative amounts to the total machine size,
while the amount of memory we want to generally be willing to yield to
system.slice is absolute (12G), we end up putting more pressure on
system.slice just because we have a larger machine and a larger workload
to fill it, which seems fairly unintuitive. With this new behaviour, we
don't end up with this unintended side effect.
Previously the way that memory.low protection works is that if you are
50% over a certain baseline, you get 50% of your normal scan pressure.
This is certainly better than the previous cliff-edge behaviour, but it
can be improved even further by always considering memory under the
currently enforced protection threshold to be out of bounds. This means
that we can set relatively low memory.low thresholds for variable or
bursty workloads while still getting a reasonable level of protection,
whereas with the previous version we may still trivially hit the 100%
clamp. The previous 100% clamp is also somewhat arbitrary, whereas this
one is more concretely based on the currently enforced protection
threshold, which is likely easier to reason about.
There is also a subtle issue with the way that proportional reclaim
worked previously -- it promotes having no memory.low, since it makes
pressure higher during low reclaim. This happens because we base our
scan pressure modulation on how far memory.current is between memory.min
and memory.low, but if memory.low is unset, we only use the overage
method. In most cromulent configurations, this then means that we end
up with *more* pressure than with no memory.low at all when we're in low
reclaim, which is not really very usable or expected.
With this patch, memory.low and memory.min affect reclaim pressure in a
more understandable and composable way. For example, from a user
standpoint, "protected" memory now remains untouchable from a reclaim
aggression standpoint, and users can also have more confidence that
bursty workloads will still receive some amount of guaranteed
protection.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Chris Down <[email protected]>
Reviewed-by: Roman Gushchin <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
Roman points out that when when we do the low reclaim pass, we scale the
reclaim pressure relative to position between 0 and the maximum
protection threshold.
However, if the maximum protection is based on memory.elow, and
memory.emin is above zero, this means we still may get binary behaviour
on second-pass low reclaim. This is because we scale starting at 0, not
starting at memory.emin, and since we don't scan at all below emin, we
end up with cliff behaviour.
This should be a fairly uncommon case since usually we don't go into the
second pass, but it makes sense to scale our low reclaim pressure
starting at emin.
You can test this by catting two large sparse files, one in a cgroup
with emin set to some moderate size compared to physical RAM, and
another cgroup without any emin. In both cgroups, set an elow larger
than 50% of physical RAM. The one with emin will have less page
scanning, as reclaim pressure is lower.
Rebase on top of and apply the same idea as what was applied to handle
cgroup_memory=disable properly for the original proportional patch
http://lkml.kernel.org/r/[email protected] ("mm,
memcg: Handle cgroup_disable=memory when getting memcg protection").
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Chris Down <[email protected]>
Suggested-by: Roman Gushchin <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Dennis Zhou <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
cgroup v2 introduces two memory protection thresholds: memory.low
(best-effort) and memory.min (hard protection). While they generally do
what they say on the tin, there is a limitation in their implementation
that makes them difficult to use effectively: that cliff behaviour often
manifests when they become eligible for reclaim. This patch implements
more intuitive and usable behaviour, where we gradually mount more
reclaim pressure as cgroups further and further exceed their protection
thresholds.
This cliff edge behaviour happens because we only choose whether or not
to reclaim based on whether the memcg is within its protection limits
(see the use of mem_cgroup_protected in shrink_node), but we don't vary
our reclaim behaviour based on this information. Imagine the following
timeline, with the numbers the lruvec size in this zone:
1. memory.low=1000000, memory.current=999999. 0 pages may be scanned.
2. memory.low=1000000, memory.current=1000000. 0 pages may be scanned.
3. memory.low=1000000, memory.current=1000001. 1000001* pages may be
scanned. (?!)
* Of course, we won't usually scan all available pages in the zone even
without this patch because of scan control priority, over-reclaim
protection, etc. However, as shown by the tests at the end, these
techniques don't sufficiently throttle such an extreme change in input,
so cliff-like behaviour isn't really averted by their existence alone.
Here's an example of how this plays out in practice. At Facebook, we are
trying to protect various workloads from "system" software, like
configuration management tools, metric collectors, etc (see this[0] case
study). In order to find a suitable memory.low value, we start by
determining the expected memory range within which the workload will be
comfortable operating. This isn't an exact science -- memory usage deemed
"comfortable" will vary over time due to user behaviour, differences in
composition of work, etc, etc. As such we need to ballpark memory.low,
but doing this is currently problematic:
1. If we end up setting it too low for the workload, it won't have
*any* effect (see discussion above). The group will receive the full
weight of reclaim and won't have any priority while competing with the
less important system software, as if we had no memory.low configured
at all.
2. Because of this behaviour, we end up erring on the side of setting
it too high, such that the comfort range is reliably covered. However,
protected memory is completely unavailable to the rest of the system,
so we might cause undue memory and IO pressure there when we *know* we
have some elasticity in the workload.
3. Even if we get the value totally right, smack in the middle of the
comfort zone, we get extreme jumps between no pressure and full
pressure that cause unpredictable pressure spikes in the workload due
to the current binary reclaim behaviour.
With this patch, we can set it to our ballpark estimation without too much
worry. Any undesirable behaviour, such as too much or too little reclaim
pressure on the workload or system will be proportional to how far our
estimation is off. This means we can set memory.low much more
conservatively and thus waste less resources *without* the risk of the
workload falling off a cliff if we overshoot.
As a more abstract technical description, this unintuitive behaviour
results in having to give high-priority workloads a large protection
buffer on top of their expected usage to function reliably, as otherwise
we have abrupt periods of dramatically increased memory pressure which
hamper performance. Having to set these thresholds so high wastes
resources and generally works against the principle of work conservation.
In addition, having proportional memory reclaim behaviour has other
benefits. Most notably, before this patch it's basically mandatory to set
memory.low to a higher than desirable value because otherwise as soon as
you exceed memory.low, all protection is lost, and all pages are eligible
to scan again. By contrast, having a gradual ramp in reclaim pressure
means that you now still get some protection when thresholds are exceeded,
which means that one can now be more comfortable setting memory.low to
lower values without worrying that all protection will be lost. This is
important because workingset size is really hard to know exactly,
especially with variable workloads, so at least getting *some* protection
if your workingset size grows larger than you expect increases user
confidence in setting memory.low without a huge buffer on top being
needed.
Thanks a lot to Johannes Weiner and Tejun Heo for their advice and
assistance in thinking about how to make this work better.
In testing these changes, I intended to verify that:
1. Changes in page scanning become gradual and proportional instead of
binary.
To test this, I experimented stepping further and further down
memory.low protection on a workload that floats around 19G workingset
when under memory.low protection, watching page scan rates for the
workload cgroup:
+------------+-----------------+--------------------+--------------+
| memory.low | test (pgscan/s) | control (pgscan/s) | % of control |
+------------+-----------------+--------------------+--------------+
| 21G | 0 | 0 | N/A |
| 17G | 867 | 3799 | 23% |
| 12G | 1203 | 3543 | 34% |
| 8G | 2534 | 3979 | 64% |
| 4G | 3980 | 4147 | 96% |
| 0 | 3799 | 3980 | 95% |
+------------+-----------------+--------------------+--------------+
As you can see, the test kernel (with a kernel containing this
patch) ramps up page scanning significantly more gradually than the
control kernel (without this patch).
2. More gradual ramp up in reclaim aggression doesn't result in
premature OOMs.
To test this, I wrote a script that slowly increments the number of
pages held by stress(1)'s --vm-keep mode until a production system
entered severe overall memory contention. This script runs in a highly
protected slice taking up the majority of available system memory.
Watching vmstat revealed that page scanning continued essentially
nominally between test and control, without causing forward reclaim
progress to become arrested.
[0]: https://facebookmicrosites.github.io/cgroup2/docs/overview.html#case-study-the-fbtax2-project
[[email protected]: reflow block comments to fit in 80 cols]
[[email protected]: handle cgroup_disable=memory when getting memcg protection]
Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Chris Down <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Reviewed-by: Roman Gushchin <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Dennis Zhou <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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The "mode" and "level" variables are enums and in this context GCC will
treat them as unsigned ints so the error handling is never triggered.
I also removed the bogus initializer because it isn't required any more
and it's sort of confusing.
[[email protected]: reduce implicit and explicit typecasting]
[[email protected]: fix return value, add comment, per Matthew]
Link: http://lkml.kernel.org/r/20190925110449.GO3264@mwanda
Fixes: 3cadfa2b9497 ("mm/vmpressure.c: convert to use match_string() helper")
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Acked-by: David Rientjes <[email protected]>
Reviewed-by: Matthew Wilcox <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Enrico Weigelt <[email protected]>
Cc: Kate Stewart <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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On architectures like s390, arch_free_page() could mark the page unused
(set_page_unused()) and any access later would trigger a kernel panic.
Fix it by moving arch_free_page() after all possible accessing calls.
Hardware name: IBM 2964 N96 400 (z/VM 6.4.0)
Krnl PSW : 0404e00180000000 0000000026c2b96e (__free_pages_ok+0x34e/0x5d8)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 0000000088d43af7 0000000000484000 000000000000007c 000000000000000f
000003d080012100 000003d080013fc0 0000000000000000 0000000000100000
00000000275cca48 0000000000000100 0000000000000008 000003d080010000
00000000000001d0 000003d000000000 0000000026c2b78a 000000002717fdb0
Krnl Code: 0000000026c2b95c: ec1100b30659 risbgn %r1,%r1,0,179,6
0000000026c2b962: e32014000036 pfd 2,1024(%r1)
#0000000026c2b968: d7ff10001000 xc 0(256,%r1),0(%r1)
>0000000026c2b96e: 41101100 la %r1,256(%r1)
0000000026c2b972: a737fff8 brctg %r3,26c2b962
0000000026c2b976: d7ff10001000 xc 0(256,%r1),0(%r1)
0000000026c2b97c: e31003400004 lg %r1,832
0000000026c2b982: ebff1430016a asi 5168(%r1),-1
Call Trace:
__free_pages_ok+0x16a/0x5d8)
memblock_free_all+0x206/0x290
mem_init+0x58/0x120
start_kernel+0x2b0/0x570
startup_continue+0x6a/0xc0
INFO: lockdep is turned off.
Last Breaking-Event-Address:
__free_pages_ok+0x372/0x5d8
Kernel panic - not syncing: Fatal exception: panic_on_oops
00: HCPGIR450W CP entered; disabled wait PSW 00020001 80000000 00000000 26A2379C
In the past, only kernel_poison_pages() would trigger this but it needs
"page_poison=on" kernel cmdline, and I suspect nobody tested that on
s390. Recently, kernel_init_free_pages() (commit 6471384af2a6 ("mm:
security: introduce init_on_alloc=1 and init_on_free=1 boot options"))
was added and could trigger this as well.
[[email protected]: add comment]
Link: http://lkml.kernel.org/r/[email protected]
Fixes: 8823b1dbc05f ("mm/page_poison.c: enable PAGE_POISONING as a separate option")
Fixes: 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Signed-off-by: Qian Cai <[email protected]>
Reviewed-by: Heiko Carstens <[email protected]>
Acked-by: Christian Borntraeger <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Alexander Duyck <[email protected]>
Cc: <[email protected]> [5.3+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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There's a really hard to reproduce race in z3fold between z3fold_free()
and z3fold_reclaim_page(). z3fold_reclaim_page() can claim the page
after z3fold_free() has checked if the page was claimed and
z3fold_free() will then schedule this page for compaction which may in
turn lead to random page faults (since that page would have been
reclaimed by then).
Fix that by claiming page in the beginning of z3fold_free() and not
forgetting to clear the claim in the end.
[[email protected]: v2]
Link: http://lkml.kernel.org/r/20190928113456.152742cf@bigdell
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Vitaly Wool <[email protected]>
Reported-by: Markus Linnala <[email protected]>
Cc: Dan Streetman <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Henry Burns <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: Markus Linnala <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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