### What this PR does / why we need it? Calculate in advance the workspace memory size needed for the PagedAttention operator to avoid deadlocks during resource cleanup. This PR requires torch_npu version 0920 or newer. ### How was this patch tested? - vLLM version: v0.11.0 --------- Signed-off-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com> Co-authored-by: wangxiaoxin-sherie <wangxiaoxin7@huawei.com>