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-rwxr-xr-xconfigure35
-rw-r--r--util/rcu.c6
2 files changed, 41 insertions, 0 deletions
diff --git a/configure b/configure
index 99ccc1725a..100309c33f 100755
--- a/configure
+++ b/configure
@@ -426,6 +426,7 @@ vxhs=""
supported_cpu="no"
supported_os="no"
bogus_os="no"
+malloc_trim=""
# parse CC options first
for opt do
@@ -1047,6 +1048,10 @@ for opt do
;;
--enable-tcg) tcg="yes"
;;
+ --disable-malloc-trim) malloc_trim="no"
+ ;;
+ --enable-malloc-trim) malloc_trim="yes"
+ ;;
--disable-spice) spice="no"
;;
--enable-spice) spice="yes"
@@ -1466,6 +1471,7 @@ Advanced options (experts only):
Default:trace-<pid>
--disable-slirp disable SLIRP userspace network connectivity
--enable-tcg-interpreter enable TCG with bytecode interpreter (TCI)
+ --enable-malloc-trim enable libc malloc_trim() for memory optimization
--oss-lib path to OSS library
--cpu=CPU Build for host CPU [$cpu]
--with-coroutine=BACKEND coroutine backend. Supported options:
@@ -3860,6 +3866,30 @@ if test "$tcmalloc" = "yes" && test "$jemalloc" = "yes" ; then
exit 1
fi
+# Even if malloc_trim() is available, these non-libc memory allocators
+# do not support it.
+if test "$tcmalloc" = "yes" || test "$jemalloc" = "yes" ; then
+ if test "$malloc_trim" = "yes" ; then
+ echo "Disabling malloc_trim with non-libc memory allocator"
+ fi
+ malloc_trim="no"
+fi
+
+#######################################
+# malloc_trim
+
+if test "$malloc_trim" != "no" ; then
+ cat > $TMPC << EOF
+#include <malloc.h>
+int main(void) { malloc_trim(0); return 0; }
+EOF
+ if compile_prog "" "" ; then
+ malloc_trim="yes"
+ else
+ malloc_trim="no"
+ fi
+fi
+
##########################################
# tcmalloc probe
@@ -5505,6 +5535,7 @@ if test "$tcg" = "yes" ; then
echo "TCG debug enabled $debug_tcg"
echo "TCG interpreter $tcg_interpreter"
fi
+echo "malloc trim support $malloc_trim"
echo "RDMA support $rdma"
echo "fdt support $fdt"
echo "preadv support $preadv"
@@ -6015,6 +6046,10 @@ if test "$opengl" = "yes" ; then
fi
fi
+if test "$malloc_trim" = "yes" ; then
+ echo "CONFIG_MALLOC_TRIM=y" >> $config_host_mak
+fi
+
if test "$avx2_opt" = "yes" ; then
echo "CONFIG_AVX2_OPT=y" >> $config_host_mak
fi
diff --git a/util/rcu.c b/util/rcu.c
index ca5a63e36a..f4d09c8304 100644
--- a/util/rcu.c
+++ b/util/rcu.c
@@ -32,6 +32,9 @@
#include "qemu/atomic.h"
#include "qemu/thread.h"
#include "qemu/main-loop.h"
+#if defined(CONFIG_MALLOC_TRIM)
+#include <malloc.h>
+#endif
/*
* Global grace period counter. Bit 0 is always one in rcu_gp_ctr.
@@ -246,6 +249,9 @@ static void *call_rcu_thread(void *opaque)
qemu_event_reset(&rcu_call_ready_event);
n = atomic_read(&rcu_call_count);
if (n == 0) {
+#if defined(CONFIG_MALLOC_TRIM)
+ malloc_trim(4 * 1024 * 1024);
+#endif
qemu_event_wait(&rcu_call_ready_event);
}
}