diff --git a/src/libarena/lib.rs b/src/libarena/lib.rs
index dae05a368fa06..955cab1d93f76 100644
--- a/src/libarena/lib.rs
+++ b/src/libarena/lib.rs
@@ -298,6 +298,7 @@ pub struct DroplessArena {
 unsafe impl Send for DroplessArena {}
 
 impl Default for DroplessArena {
+    #[inline]
     fn default() -> DroplessArena {
         DroplessArena {
             ptr: Cell::new(0 as *mut u8),
@@ -319,6 +320,7 @@ impl DroplessArena {
         false
     }
 
+    #[inline]
     fn align(&self, align: usize) {
         let final_address = ((self.ptr.get() as usize) + align - 1) & !(align - 1);
         self.ptr.set(final_address as *mut u8);
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 57b5903c9d39f..c87dcbe500cba 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -3614,6 +3614,7 @@ assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));
 assert_eq!(", stringify!($SelfT), "::max_value().checked_next_power_of_two(), None);",
 $EndFeature, "
 ```"),
+            #[inline]
             #[stable(feature = "rust1", since = "1.0.0")]
             pub fn checked_next_power_of_two(self) -> Option<Self> {
                 self.one_less_than_next_power_of_two().checked_add(1)
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index 7c717d832fa54..349aa029ba8cb 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -849,6 +849,7 @@ impl<K, V, S> HashMap<K, V, S>
     /// let mut map: HashMap<&str, i32> = HashMap::new();
     /// map.reserve(10);
     /// ```
+    #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn reserve(&mut self, additional: usize) {
         match self.reserve_internal(additional, Infallible) {
@@ -880,6 +881,7 @@ impl<K, V, S> HashMap<K, V, S>
         self.reserve_internal(additional, Fallible)
     }
 
+    #[inline]
     fn reserve_internal(&mut self, additional: usize, fallibility: Fallibility)
         -> Result<(), CollectionAllocErr> {
 
@@ -1571,6 +1573,7 @@ impl<K, V, S> HashMap<K, V, S>
     /// so that the map now contains keys which compare equal, search may start
     /// acting erratically, with two keys randomly masking each other. Implementations
     /// are free to assume this doesn't happen (within the limits of memory-safety).
+    #[inline(always)]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn raw_entry_mut(&mut self) -> RawEntryBuilderMut<K, V, S> {
         self.reserve(1);
@@ -1911,6 +1914,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
     }
 
     /// Create a `RawEntryMut` from the given key and its hash.
+    #[inline]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn from_key_hashed_nocheck<Q: ?Sized>(self, hash: u64, k: &Q) -> RawEntryMut<'a, K, V, S>
         where K: Borrow<Q>,
@@ -1919,6 +1923,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
         self.from_hash(hash, |q| q.borrow().eq(k))
     }
 
+    #[inline]
     fn search<F>(self, hash: u64, is_match: F, compare_hashes: bool)  -> RawEntryMut<'a, K, V, S>
         where for<'b> F: FnMut(&'b K) -> bool,
     {
@@ -1941,6 +1946,7 @@ impl<'a, K, V, S> RawEntryBuilderMut<'a, K, V, S>
         }
     }
     /// Create a `RawEntryMut` from the given hash.
+    #[inline]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn from_hash<F>(self, hash: u64, is_match: F) -> RawEntryMut<'a, K, V, S>
         where for<'b> F: FnMut(&'b K) -> bool,
@@ -2215,6 +2221,7 @@ impl<'a, K, V, S> RawVacantEntryMut<'a, K, V, S> {
 
     /// Sets the value of the entry with the VacantEntry's key,
     /// and returns a mutable reference to it.
+    #[inline]
     #[unstable(feature = "hash_raw_entry", issue = "56167")]
     pub fn insert_hashed_nocheck(self, hash: u64, key: K, value: V) -> (&'a mut K, &'a mut V) {
         let hash = SafeHash::new(hash);
diff --git a/src/libstd/collections/hash/table.rs b/src/libstd/collections/hash/table.rs
index 547f97cc8acee..479e6dccb90dd 100644
--- a/src/libstd/collections/hash/table.rs
+++ b/src/libstd/collections/hash/table.rs
@@ -329,6 +329,7 @@ impl<K, V, M> Put<K, V> for FullBucket<K, V, M>
 }
 
 impl<K, V, M: Deref<Target = RawTable<K, V>>> Bucket<K, V, M> {
+    #[inline]
     pub fn new(table: M, hash: SafeHash) -> Bucket<K, V, M> {
         Bucket::at_index(table, hash.inspect() as usize)
     }
@@ -342,6 +343,7 @@ impl<K, V, M: Deref<Target = RawTable<K, V>>> Bucket<K, V, M> {
         }
     }
 
+    #[inline]
     pub fn at_index(table: M, ib_index: usize) -> Bucket<K, V, M> {
         // if capacity is 0, then the RawBucket will be populated with bogus pointers.
         // This is an uncommon case though, so avoid it in release builds.
@@ -654,6 +656,7 @@ impl<K, V, M> GapThenFull<K, V, M>
 
 // Returns a Layout which describes the allocation required for a hash table,
 // and the offset of the array of (key, value) pairs in the allocation.
+#[inline(always)]
 fn calculate_layout<K, V>(capacity: usize) -> Result<(Layout, usize), LayoutErr> {
     let hashes = Layout::array::<HashUint>(capacity)?;
     let pairs = Layout::array::<(K, V)>(capacity)?;
@@ -722,6 +725,7 @@ impl<K, V> RawTable<K, V> {
         }
     }
 
+    #[inline(always)]
     fn raw_bucket_at(&self, index: usize) -> RawBucket<K, V> {
         let (_, pairs_offset) = calculate_layout::<K, V>(self.capacity())
             .unwrap_or_else(|_| unsafe { hint::unreachable_unchecked() });