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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 17:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-08 17:28:57 -0700
commit3431a940bb6c3969240d91314d654ebac7e12b09 (patch)
tree8d75363fe5bc959bf03d72bc1c00275fb759f153 /arch
parent5b7a2095232d026d4537c4be54040c0f10525b5b (diff)
parent711486fd18596315d42cebaac3dba8c408f60a3d (diff)
Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 AVX512 status update from Ingo Molnar: "This adds a new ABI that the main scheduler probably doesn't want to deal with but HPC job schedulers might want to use: the AVX512_elapsed_ms field in the new /proc/<pid>/arch_status task status file, which allows the user-space job scheduler to cluster such tasks, to avoid turbo frequency drops" * 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Documentation/filesystems/proc.txt: Add arch_status file x86/process: Add AVX-512 usage elapsed time to /proc/pid/arch_status proc: Add /proc/<pid>/arch_status
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/Kconfig1
-rw-r--r--arch/x86/kernel/fpu/xstate.c47
2 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fbabf59692ff..3b3acb7f1b07 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -220,6 +220,7 @@ config X86
select USER_STACKTRACE_SUPPORT
select VIRT_TO_BUS
select X86_FEATURE_NAMES if PROC_FS
+ select PROC_PID_ARCH_STATUS if PROC_FS
config INSTRUCTION_DECODER
def_bool y
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 7b4c52aa929f..e5cb67d67c03 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -8,6 +8,8 @@
#include <linux/cpu.h>
#include <linux/mman.h>
#include <linux/pkeys.h>
+#include <linux/seq_file.h>
+#include <linux/proc_fs.h>
#include <asm/fpu/api.h>
#include <asm/fpu/internal.h>
@@ -1231,3 +1233,48 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf)
return 0;
}
+
+#ifdef CONFIG_PROC_PID_ARCH_STATUS
+/*
+ * Report the amount of time elapsed in millisecond since last AVX512
+ * use in the task.
+ */
+static void avx512_status(struct seq_file *m, struct task_struct *task)
+{
+ unsigned long timestamp = READ_ONCE(task->thread.fpu.avx512_timestamp);
+ long delta;
+
+ if (!timestamp) {
+ /*
+ * Report -1 if no AVX512 usage
+ */
+ delta = -1;
+ } else {
+ delta = (long)(jiffies - timestamp);
+ /*
+ * Cap to LONG_MAX if time difference > LONG_MAX
+ */
+ if (delta < 0)
+ delta = LONG_MAX;
+ delta = jiffies_to_msecs(delta);
+ }
+
+ seq_put_decimal_ll(m, "AVX512_elapsed_ms:\t", delta);
+ seq_putc(m, '\n');
+}
+
+/*
+ * Report architecture specific information
+ */
+int proc_pid_arch_status(struct seq_file *m, struct pid_namespace *ns,
+ struct pid *pid, struct task_struct *task)
+{
+ /*
+ * Report AVX512 state if the processor and build option supported.
+ */
+ if (cpu_feature_enabled(X86_FEATURE_AVX512F))
+ avx512_status(m, task);
+
+ return 0;
+}
+#endif /* CONFIG_PROC_PID_ARCH_STATUS */