diff --git a/router/src/infer/v3/block_allocator.rs b/router/src/infer/v3/block_allocator.rs
index 0d6c7cfa..a084a505 100644
--- a/router/src/infer/v3/block_allocator.rs
+++ b/router/src/infer/v3/block_allocator.rs
@@ -1,44 +1,55 @@
-use std::cmp::min;
 use std::sync::{Arc, Mutex};
 use thiserror::Error;
 
 #[derive(Debug, Clone)]
 pub(crate) struct BlockAllocation {
-    pub blocks: Vec<u32>,
-    pub slots: Vec<u32>,
-    prompt_tokens: u32,
-    decode_tokens: u32,
+    allocated_blocks: Vec<u32>,
+    allocated_slots: Vec<u32>,
+    required_blocks: usize,
+    required_slots: usize,
     block_allocator: BlockAllocator,
 }
 
 impl BlockAllocation {
     pub(crate) fn len(&self) -> usize {
-        self.slots.len()
+        self.allocated_slots.len()
+    }
+
+    pub(crate) fn blocks(&self) -> &[u32] {
+        &self.allocated_blocks
+    }
+
+    pub(crate) fn slots(&self) -> &[u32] {
+        &self.allocated_slots
     }
 
     pub(crate) fn extend(&mut self) -> Result<(), AllocationError> {
         let (block, slots) = self.block_allocator.allocate_block()?;
+        // Add block and slots to current allocation
+        self.allocated_blocks.push(block);
+        self.allocated_slots.extend(slots);
 
-        match self.block_allocator.window_size {
-            None => {
-                self.blocks.push(block);
-                self.slots.extend(slots);
-            }
-            Some(window_size) => {
-                if self.len() as u32 > window_size {
-                    let total_tokens = self.prompt_tokens + self.decode_tokens;
-
-                    let repeats = (total_tokens + window_size - 1) / window_size;
-                }
+        if let Some(window_size) = self.block_allocator.window_size {
+            // if we have more slots than the window size,
+            // we will never need to re-allocate and we can just repeat the blocks/slots
+            let window_size = window_size as usize;
+            if self.len() > window_size {
+                let repeats = (self.required_slots + window_size - 1) / window_size;
+                self.allocated_blocks = self.allocated_blocks.repeat(repeats);
+                self.allocated_blocks.truncate(self.required_blocks);
+                self.allocated_slots = self.allocated_slots.repeat(repeats);
+                self.allocated_slots.truncate(self.required_slots);
             }
         }
+
         Ok(())
     }
 }
 
 impl Drop for BlockAllocation {
     fn drop(&mut self) {
-        self.block_allocator.free(self.blocks.clone())
+        let allocated_blocks = std::mem::take(&mut self.allocated_blocks);
+        self.block_allocator.free(allocated_blocks)
     }
 }
 
@@ -82,85 +93,76 @@ impl BlockAllocator {
     /// For decode tokens, we allocate block by block
     ///
     /// If prompt tokens + min(decode_tokens, block_size) > window size, we repeat blocks and slots
-    fn allocate(
-        &self,
-        prompt_tokens: u32,
-        decode_tokens: u32,
-    ) -> Result<(Vec<u32>, Vec<u32>), AllocationError> {
-        // let decode_tokens = min(decode_tokens, self.block_size);
-        // let tokens = prompt_tokens + decode_tokens;
-
-        let required_prompt_blocks = (prompt_tokens + self.block_size - 1) / self.block_size;
-        // prompt blocks + a single block for decode
-        let required_blocks = required_prompt_blocks + 1;
-
-        let (required_blocks, repeats) = match self.window_size {
-            // Nothing to do
-            None => (required_blocks, 1),
-            Some(window_size) => {
-                // Number of blocks needed for this window size
-                let window_size_required_blocks = (window_size + self.block_size - 1) / self.block_size;
-                // Number of times we will need to repeat blocks to cover the required allocation
-                let repeats = (required_blocks + window_size_required_blocks -1) / window_size_required_blocks;
-                let required_blocks = min(required_blocks, window_size_required_blocks);
-
-                (required_blocks, repeats)
-            }
-        };
-
-
-        /// if prompt + decode < window size => do nothing
-        /// if prompt + decode > window size => do normal until we reach window size then
-
-        // Apply window size
-        let (required_blocks, repeats) = {
-            let (tokens, repeats) = match self.window_size {
-                None => (tokens, 1),
-                Some(window_size) => {
-                    let repeats = (tokens + window_size - 1) / window_size;
-                    let tokens = min(tokens, window_size);
-                    (tokens, repeats as usize)
-                }
-            };
-            // Pad to a multiple of block size
-            let required_blocks = (tokens + self.block_size - 1) / self.block_size;
-            (required_blocks, repeats)
-        };
-
-        let mut free_blocks = self.free_blocks.lock().expect("Lock could not be acquired");
-
-        if required_blocks > free_blocks.len() as u32 {
-            Err(AllocationError::NotEnoughPages)
-        } else {
-            let n_free_blocks = free_blocks.len();
-            let blocks =
-                free_blocks.split_off(n_free_blocks - required_blocks as usize);
-            let mut slots = Vec::with_capacity(
-                (required_blocks * self.block_size * repeats as u32) as usize,
-            );
-
-            for block_id in blocks.repeat(repeats).iter() {
-                for s in (block_id * self.block_size)..((block_id + 1) * self.block_size) {
-                    slots.push(s);
-                }
-            }
-            Ok((blocks, slots))
-        }
-    }
-
     pub(crate) fn block_allocation(
         &self,
         prompt_tokens: u32,
         decode_tokens: u32,
     ) -> Result<BlockAllocation, AllocationError> {
-        self.allocate_inner(prompt_tokens, decode_tokens)
-            .map(|(blocks, slots)| BlockAllocation {
-                blocks,
-                slots,
-                prompt_tokens,
-                decode_tokens,
+        let required_prompt_blocks = (prompt_tokens + self.block_size - 1) / self.block_size;
+        // prompt blocks + a single block for decode
+        let required_blocks = required_prompt_blocks + 1;
+
+        let (clipped_required_blocks, repeats) = match self.window_size {
+            // Nothing to do
+            None => (required_blocks, 1),
+            Some(window_size) => {
+                // Number of blocks for this window size
+                let window_size_blocks = (window_size + self.block_size - 1) / self.block_size;
+
+                if required_blocks > window_size_blocks {
+                    // Number of times we will need to repeat blocks to cover the required allocation
+                    let repeats = (required_blocks + window_size_blocks - 1) / window_size_blocks;
+                    (window_size_blocks, repeats)
+                } else {
+                    (required_blocks, 1)
+                }
+            }
+        };
+
+        let repeats = repeats as usize;
+        let required_blocks = required_blocks as usize;
+        let clipped_required_blocks = clipped_required_blocks as usize;
+
+        let mut free_blocks = self.free_blocks.lock().expect("Lock could not be acquired");
+
+        if clipped_required_blocks > free_blocks.len() {
+            Err(AllocationError::NotEnoughPages)
+        } else {
+            let n_free_blocks = free_blocks.len();
+            let allocated_blocks =
+                free_blocks.split_off(n_free_blocks - clipped_required_blocks);
+
+            let allocated_blocks = if repeats != 1 {
+                let mut allocated_blocks = allocated_blocks.repeat(repeats);
+                allocated_blocks.truncate(required_blocks);
+                allocated_blocks
+            } else {
+                allocated_blocks
+            };
+
+            let mut allocated_slots = Vec::with_capacity(
+                allocated_blocks.len() * self.block_size as usize * repeats,
+            );
+
+            let required_slots = (prompt_tokens + decode_tokens) as usize;
+
+            'slots: for block_id in allocated_blocks.iter() {
+                for s in (block_id * self.block_size)..((block_id + 1) * self.block_size) {
+                    allocated_slots.push(s);
+                    if allocated_slots.len() > required_slots {
+                        break 'slots;
+                    }
+                }
+            }
+
+            Ok(BlockAllocation {
+                allocated_blocks,
+                allocated_slots,
+                required_blocks,
+                required_slots,
                 block_allocator: self.clone(),
             })
+        }
     }
 
     pub(crate) fn free(&self, blocks: Vec<u32>) {
diff --git a/router/src/infer/v3/queue.rs b/router/src/infer/v3/queue.rs
index 14e67fff..db09f9b4 100644
--- a/router/src/infer/v3/queue.rs
+++ b/router/src/infer/v3/queue.rs
@@ -283,7 +283,7 @@ impl State {
                     let decode_tokens =
                         entry.request.stopping_parameters.max_new_tokens + self.speculate;
                     match block_allocator
-                        .allocate(entry.request.input_length, decode_tokens)
+                        .block_allocation(entry.request.input_length, decode_tokens)
                     {
                         Err(_) => {
                             // Entry is over budget
@@ -294,7 +294,7 @@ impl State {
                         }
                         Ok(block_allocation) => {
                             tracing::debug!("Allocation: {block_allocation:?}");
-                            max_blocks = max(max_blocks, block_allocation.blocks.len() as u32);
+                            max_blocks = max(max_blocks, block_allocation.blocks().len() as u32);
                             Some(block_allocation)
                         }
                     }
@@ -313,8 +313,8 @@ impl State {
             let (blocks, slots) = match &block_allocation {
                 None => (Vec::new(), Vec::new()),
                 Some(block_allocation) => (
-                    block_allocation.blocks.clone(),
-                    block_allocation.slots.clone(),
+                    block_allocation.blocks().to_vec(),
+                    block_allocation.slots().to_vec(),
                 ),
             };
 
diff --git a/router/src/infer/v3/scheduler.rs b/router/src/infer/v3/scheduler.rs
index 0913f495..5fb9e11d 100644
--- a/router/src/infer/v3/scheduler.rs
+++ b/router/src/infer/v3/scheduler.rs
@@ -347,7 +347,7 @@ async fn filter_batch(
                 let (blocks, slots) = entry
                     .block_allocation
                     .as_ref()
-                    .map(|alloc| (alloc.blocks.clone(), alloc.slots.clone()))
+                    .map(|alloc| (alloc.blocks().to_vec(), alloc.slots().to_vec()))
                     .unwrap_or((Vec::new(), Vec::new()));
 
                 KeptRequest {