From a08b640fa72bf603c8fd24cbe7700543a1a73cf5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Botond=20D=C3=A9nes?= <bdenes@scylladb.com>
Date: Mon, 2 Nov 2020 15:45:45 +0200
Subject: [PATCH] utils/large_bitset: use reserve_partial() to reserve _storage

To avoid stalls when reserving memory for a large bloom filter. The
filter creation already has a yielding loop for initialization, this
patch extends it to reservation of memory too.
---
 utils/large_bitset.cc | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/utils/large_bitset.cc b/utils/large_bitset.cc
index f72893236b..161ffef18f 100644
--- a/utils/large_bitset.cc
+++ b/utils/large_bitset.cc
@@ -30,8 +30,15 @@ using namespace seastar;
 large_bitset::large_bitset(size_t nr_bits) : _nr_bits(nr_bits) {
     assert(thread::running_in_thread());
 
-    size_t nr_ints = align_up(nr_bits, bits_per_int()) / bits_per_int();
-    _storage.reserve(nr_ints);
+    const size_t orig_nr_ints = align_up(nr_bits, bits_per_int()) / bits_per_int();
+    auto nr_ints = orig_nr_ints;
+    while (nr_ints) {
+        nr_ints = _storage.reserve_partial(nr_ints);
+        if (need_preempt()) {
+            thread::yield();
+        }
+    }
+    nr_ints = orig_nr_ints;
     while (nr_ints) {
         _storage.push_back(0);
         --nr_ints;