Hi On Thu, Nov 23, 2017 at 7:41 AM, Yang Zhong <yang.zh...@intel.com> wrote: > Since there are some issues in memory alloc/free machenism > in glibc for little chunk memory, if Qemu frequently > alloc/free little chunk memory, the glibc doesn't alloc > little chunk memory from free list of glibc and still > allocate from OS, which make the heap size bigger and bigger. > > This patch introduce malloc_trim(), which will free heap memory. > > Below are test results from smaps file. > (1)without patch > 55f0783e1000-55f07992a000 rw-p 00000000 00:00 0 [heap] > Size: 21796 kB > Rss: 14260 kB > Pss: 14260 kB > > (2)with patch > 55cc5fadf000-55cc61008000 rw-p 00000000 00:00 0 [heap] > Size: 21668 kB > Rss: 6940 kB > Pss: 6940 kB
Have you opened a bug to glibc malloc (or discussed that issue with the glibc malloc developpers) ? Or is there a justification that qemu should have its own trim heuristic on top of malloc? > > Signed-off-by: Yang Zhong <yang.zh...@intel.com> > --- > configure | 4 ++++ > util/rcu.c | 6 ++++++ > 2 files changed, 10 insertions(+) > > diff --git a/configure b/configure > index 0e856bb..5b463d4 100755 > --- a/configure > +++ b/configure > @@ -6012,6 +6012,10 @@ if test "$opengl" = "yes" ; then > fi > fi > > +if test "$tcmalloc" = "yes" || test "$jemalloc" = "yes" ; then > + echo "CONFIG_NONGLIBMALLOC=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 ca5a63e..f3e96a8 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_LINUX) > +#include <malloc.h> > +#endif > > /* > * Global grace period counter. Bit 0 is always one in rcu_gp_ctr. > @@ -272,6 +275,9 @@ static void *call_rcu_thread(void *opaque) > node->func(node); > } > qemu_mutex_unlock_iothread(); > +#if defined(CONFIG_LINUX) && !defined(CONFIG_NONGLIBMALLOC) > + malloc_trim(4 * 1024 * 1024); > +#endif > } > abort(); > } > -- > 1.9.1 > > -- Marc-André Lureau
