[lldb] Conditionalize context_switch attribute based on kernel version

[root-kidik]

Close: #105705

I build llvm toolchain with linux-headers 4.2, but get error, while compiling lldb

llvm-project/lldb/source/Plugins/Process/Linux/Perf.cpp:345:8: error: 'struct perf_event_attr' has no member named 'context_switch' attr.context_switch = 1%3b

can we replace or disable this functionality in lldb with older linux-headers?

https://man7.org/linux/man-pages/man2/perf_event_open.2.html
context_switch (since Linux 4.3)

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[llvmbot]

@llvm/pr-subscribers-lldb

Author: Nikita (root-kidik)

Changes

Close: #105705

---

Full diff: https://github.com/llvm/llvm-project/pull/105715.diff

1 Files Affected:

• (modified) lldb/source/Plugins/Process/Linux/Perf.cpp (+2)

diff --git a/lldb/source/Plugins/Process/Linux/Perf.cpp b/lldb/source/Plugins/Process/Linux/Perf.cpp
index 097c719b9c1d25..8135d092cfdd68 100644
--- a/lldb/source/Plugins/Process/Linux/Perf.cpp
+++ b/lldb/source/Plugins/Process/Linux/Perf.cpp
@@ -342,7 +342,9 @@ lldb_private::process_linux::CreateContextSwitchTracePerfEvent(
   attr.size = sizeof(attr);
   attr.sample_type = PERF_SAMPLE_TID | PERF_SAMPLE_TIME;
   attr.type = PERF_TYPE_SOFTWARE;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 3, 0)
   attr.context_switch = 1;
+#endif
   attr.exclude_kernel = 1;
   attr.sample_id_all = 1;
   attr.exclude_hv = 1;

[JDevlieghere]

The change itself looks fine, but can you please update the PR description with a meaningful message, preferably with a reference that shows that this was added in 4.3?

[root-kidik]

Ping