Fix massif --pages-as-heap=yes does not report peak caused by mmap+munmap

ms_unrecord_page_mem was wrongly taking the (possible) peak snapshot
when unrecording the last block.
But the peak snapshot will be detected when unrecording the first block
of an munmap, not when unrecording the last block.



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15745

NEWS

@@ -52,11 +52,12 @@ where XXXXXX is the bug number as listed below.
 354797  Added vbit tester support for PPC 64 isa 2.07 iops
 354933  Fix documentation of --kernel-variant=android-no-hw-tls option
 355188  valgrind should intercept all malloc related global functions
-355455  expected stderr of test cases wrapmalloc and wrapmallocstatic overconstrained
+355455  stderr.exp of test cases wrapmalloc and wrapmallocstatic overconstrained
 355454  do not intercept malloc related symbols from the runtime linker
 356044  Dwarf line info reader misinterprets is_stmt register
 
 n-i-bz Fix incorrect (or infinite loop) unwind on RHEL7 x86 32 bits
+n-i-bz massif --pages-as-heap=yes does not report peak caused by mmap+munmap
 
 Release 3.11.0 (22 September 2015)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

massif/ms_main.c

@@ -1816,10 +1816,13 @@ void ms_unrecord_page_mem( Addr a, SizeT len )
    Addr end;
    tl_assert(VG_IS_PAGE_ALIGNED(len));
    tl_assert(len >= VKI_PAGE_SIZE);
+   // Unrecord the first page. This might be the peak, so do a snapshot.
+   unrecord_block((void*)a, /*maybe_snapshot*/True);
+   a += VKI_PAGE_SIZE;
+   // Then unrecord the remaining pages, but without snapshots.
    for (end = a + len - VKI_PAGE_SIZE; a < end; a += VKI_PAGE_SIZE) {
       unrecord_block((void*)a, /*maybe_snapshot*/False);
    }
-   unrecord_block((void*)a, /*maybe_snapshot*/True);
 }
 
 //------------------------------------------------------------//

massif/tests/Makefile.am

@@ -24,6 +24,7 @@ EXTRA_DIST = \
 	long-names.post.exp long-names.stderr.exp long-names.vgtest \
 	long-time.post.exp long-time.stderr.exp long-time.vgtest \
 	malloc_usable.stderr.exp malloc_usable.vgtest \
+	mmapunmap.post.exp mmapunmap.stderr.exp mmapunmap.vgtest \
 	new-cpp.post.exp new-cpp.stderr.exp new-cpp.vgtest \
 	no-stack-no-heap.post.exp no-stack-no-heap.stderr.exp no-stack-no-heap.vgtest \
 	null.post.exp null.stderr.exp null.vgtest \
@@ -61,6 +62,7 @@ check_PROGRAMS = \
 	insig \
 	long-names \
 	long-time \
+	mmapunmap \
 	malloc_usable \
 	new-cpp \
 	null \

massif/tests/mmapunmap.c

@@ -0,0 +1,16 @@
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include "tests/sys_mman.h"
+
+int main()
+{
+   void *m;
+
+   m = mmap(NULL, 80 * 1000 * 1024,
+            PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS,
+            -1, 0);
+   munmap(m, 80 * 1000 * 1024);
+   return 0;
+}

massif/tests/mmapunmap.post.exp

@@ -0,0 +1 @@
+  n0: 81920000 0x........: main (mmapunmap.c:11)

massif/tests/mmapunmap.vgtest

@@ -0,0 +1,6 @@
+prog: mmapunmap
+vgopts: --pages-as-heap=yes --threshold=30.0 -q
+vgopts: --stacks=no --time-unit=B --depth=8 --massif-out-file=massif.out
+vgopts: --ignore-fn=__part_load_locale --ignore-fn=__time_load_locale --ignore-fn=dwarf2_unwind_dyld_add_image_hook --ignore-fn=get_or_create_key_element
+post: grep -A3 -e =peak massif.out | grep -e 'main (mmapunmap.c:11)' | ../../tests/filter_addresses
+# cleanup: rm massif.out