Merge pull request #547 from LibreQoE/issue_518_reloading_2

Issue 518 reloading 2

src/rust/lqos_sys/src/bpf_map.rs

@@ -1,15 +1,15 @@
 #![allow(dead_code)]
-use anyhow::{Error, Result};
-use libbpf_sys::{
-  bpf_map_delete_elem, bpf_map_get_next_key, bpf_map_lookup_elem,
-  bpf_map_update_elem, bpf_obj_get, BPF_NOEXIST,
-};
 use std::{
     ffi::{c_void, CString},
     marker::PhantomData,
     ptr::null_mut,
 };
 
+use anyhow::{Error, Result};
+use libbpf_sys::{bpf_map_delete_elem, bpf_map_get_next_key, bpf_map_lookup_elem, bpf_map_update_elem, BPF_NOEXIST, bpf_obj_get};
+
+use crate::lqos_kernel::bpf::bpf_map_delete_batch;
+
 /// Represents an underlying BPF map, accessed via the filesystem.
 /// `BpfMap` *only* talks to shared (not PER-CPU) variants of maps.
 ///
@@ -39,7 +39,7 @@ where
         }
     }
 
-  /// Iterates the undlering BPF map, and adds the results
+    /// Iterates the underlying BPF map, and adds the results
     /// to a vector. Each entry contains a `key, value` tuple.
     ///
     /// This has performance issues due to excessive cloning
@@ -220,6 +220,24 @@ where
         }
         Ok(())
     }
+
+    /// Clears an eBPF map using `bpf_map_delete_batch`, which
+    /// has better locking semantics than per-row.
+    pub fn clear_bulk(&mut self) -> Result<()> {
+        let mut keys: Vec<K> = self.dump_vec().iter().map(|(k, _)| {
+            k.clone()
+        }).collect();
+        let mut count = keys.len() as u32;
+        loop {
+            let ret = unsafe {
+                bpf_map_delete_batch(self.fd, keys.as_mut_ptr() as *mut c_void, &mut count, null_mut())
+            };
+            if ret != 0 || count == 0 {
+                break;
+            }
+        }
+        Ok(())
+    }
 }
 
 impl<K, V> Drop for BpfMap<K, V> {

src/rust/lqos_sys/src/ip_mapping/mod.rs

@@ -100,6 +100,6 @@ pub fn list_mapped_ips() -> Result<Vec<(IpHashKey, IpHashData)>> {
 /// destinations.
 pub fn clear_hot_cache() -> Result<()> {
   let mut bpf_map = BpfMap::<XdpIpAddress, IpHashData>::from_path("/sys/fs/bpf/ip_to_cpu_and_tc_hotcache")?;
-  bpf_map.clear()?;
+  bpf_map.clear_bulk()?;
   Ok(())
 }