From: Waldemar Kozaczuk <[email protected]>
Committer: Nadav Har'El <[email protected]>
Branch: master
Handle small memory allocations ( < 16 bytes) more space efficiently
This patch adjusts std_malloc() to handle small
allocations (smaller than 16-bytes) more efficiently.
More specifically instead of allocating whole page
for each such request, adjusted std_malloc() uses memory
pool adequate to requested size and thus saves almost
entire page (4K) of memory.
Fixes #1011
Signed-off-by: Waldemar Kozaczuk <[email protected]>
Message-Id: <[email protected]>
---
diff --git a/core/mempool.cc b/core/mempool.cc
--- a/core/mempool.cc
+++ b/core/mempool.cc
@@ -1546,8 +1546,9 @@ static inline void* std_malloc(size_t size, size_t
alignment)
if ((ssize_t)size < 0)
return libc_error_ptr<void *>(ENOMEM);
void *ret;
- if (size <= memory::pool::max_object_size && alignment <= size &&
smp_allocator) {
- size = std::max(size, memory::pool::min_object_size);
+ size_t minimum_size = std::max(size, memory::pool::min_object_size);
+ if (size <= memory::pool::max_object_size && alignment <= minimum_size
&& smp_allocator) {
+ size = minimum_size;
unsigned n = ilog2_roundup(size);
ret = memory::malloc_pools[n].alloc();
ret = translate_mem_area(mmu::mem_area::main,
mmu::mem_area::mempool,
diff --git a/modules/tests/Makefile b/modules/tests/Makefile
--- a/modules/tests/Makefile
+++ b/modules/tests/Makefile
@@ -116,7 +116,7 @@ tests := tst-pthread.so misc-ramdisk.so tst-vblk.so
tst-bsd-evh.so \
tst-ifaddrs.so tst-pthread-affinity-inherit.so tst-sem-timed-wait.so \
tst-ttyname.so tst-pthread-barrier.so tst-feexcept.so tst-math.so \
tst-sigaltstack.so tst-fread.so tst-tcp-cork.so tst-tcp-v6.so \
- tst-calloc.so tst-crypt.so tst-non-fpic.so
+ tst-calloc.so tst-crypt.so tst-non-fpic.so tst-small-malloc.so
# libstatic-thread-variable.so tst-static-thread-variable.so \
diff --git a/tests/tst-small-malloc.cc b/tests/tst-small-malloc.cc
--- a/tests/tst-small-malloc.cc
+++ b/tests/tst-small-malloc.cc
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2018 Waldemar Kozaczuk
+ *
+ * This work is open source software, licensed under the terms of the
+ * BSD license as described in the LICENSE file in the top-level directory.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <cassert>
+#include <osv/trace-count.hh>
+
+int main() {
+ tracepoint_counter *memory_malloc_mempool_counter = nullptr,
+ *memory_malloc_page_counter = nullptr;
+
+ for (auto & tp : tracepoint_base::tp_list) {
+ if ("memory_malloc_mempool" == std::string(tp.name)) {
+ memory_malloc_mempool_counter = new tracepoint_counter(tp);
+ }
+ if ("memory_malloc_page" == std::string(tp.name)) {
+ memory_malloc_page_counter = new tracepoint_counter(tp);
+ }
+ }
+ assert(memory_malloc_mempool_counter != nullptr);
+ assert(memory_malloc_page_counter != nullptr);
+
+ auto memory_malloc_mempool_counter_now =
memory_malloc_mempool_counter->read();
+ auto memory_malloc_page_counter_now =
memory_malloc_page_counter->read();
+
+ const int allocation_count = 1024;
+ for( int i = 0; i < allocation_count; i++) {
+ void *addr = malloc(7);
+ assert(addr);
+ free(addr);
+
+ addr = malloc(17);
+ assert(addr);
+ free(addr);
+ }
+
+ // Verify all allocations above were handled by malloc_pool
+ assert(memory_malloc_mempool_counter->read() -
memory_malloc_mempool_counter_now >= 2 * allocation_count);
+ // Verify that NO allocations were handled by alloc_page
+ assert(memory_malloc_page_counter->read() -
memory_malloc_page_counter_now == 0);
+}
\ No newline at end of file
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