Because these register sets are incredibly large, the CPU cannot automatically save or restore them during a typical context switch without severely damaging system performance. The Linux kernel uses struct fpstate to allocate memory dynamically depending on the exact hardware features supported by the CPU.
When a signal occurs, the kernel must save the current FPU state to the user's stack frame (the sigframe ). The fpstate vso logic ensures the correct amount of data is copied so that floating-point operations can resume accurately after the signal handler finishes.
This refers to the data structure that stores the state of a CPU's Floating-Point Unit (FPU) . When a computer switches between different tasks (context switching), the kernel must save the current task's math registers (like SSE, AVX, or AVX-512) into an fpstate area so they can be restored later without losing data. fpstate vso
The use of FPState VSO in virtualized environments offers several benefits:
Ensuring that simulated backend VSOs in test environments accurately reflect the real-world state of the microservices they are replacing. Summary and Moving Forward Because these register sets are incredibly large, the
Tracing memory leaks and register corruption in highly concurrent, multithreaded applications.
The struct fpstate is defined in the Linux kernel source (as of version 5.19) and looks like this: The fpstate vso logic ensures the correct amount
The map_vdso function is defined in the same source code file and maps pages for the vDSO and for the shared vDSO variables. That' 0xax.gitbooks.io vdso(7) - Linux manual page - man7.org