From c811fa61155576b21fe17f00445ba764f3ff6674 Mon Sep 17 00:00:00 2001 From: Nahim El Atmani Date: Sat, 5 Mar 2016 13:35:57 +0100 Subject: [PATCH] Reduce memory usage while managing tcbs allocation. * strace.c (init): Remove initial memory allocation for tcbtab. (expand_tcbtab): Do initial memory allocation when tcbtabsize == 0. Signed-off-by: Nahim El Atmani Reviewed-By: Gabriel Laskar Reported-by: haris iqbal Signed-off-by: Dmitry V. Levin --- strace.c | 33 +++++++++++++++------------------ 1 file changed, 15 insertions(+), 18 deletions(-) diff --git a/strace.c b/strace.c index 785cc605..49d6f3d6 100644 --- a/strace.c +++ b/strace.c @@ -691,19 +691,25 @@ newoutf(struct tcb *tcp) static void expand_tcbtab(void) { - /* Allocate some more TCBs and expand the table. + /* Allocate some (more) TCBs (and expand the table). We don't want to relocate the TCBs because our callers have pointers and it would be a pain. So tcbtab is a table of pointers. Since we never free the TCBs, we allocate a single chunk of many. */ - unsigned int i = tcbtabsize; - struct tcb *newtcbs = xcalloc(tcbtabsize, sizeof(newtcbs[0])); - struct tcb **newtab = xreallocarray(tcbtab, tcbtabsize * 2, - sizeof(tcbtab[0])); - tcbtabsize *= 2; - tcbtab = newtab; - while (i < tcbtabsize) - tcbtab[i++] = newtcbs++; + unsigned int new_tcbtabsize, alloc_tcbtabsize; + struct tcb *newtcbs; + + if (tcbtabsize) { + alloc_tcbtabsize = tcbtabsize; + new_tcbtabsize = tcbtabsize * 2; + } else { + new_tcbtabsize = alloc_tcbtabsize = 1; + } + + newtcbs = xcalloc(alloc_tcbtabsize, sizeof(newtcbs[0])); + tcbtab = xreallocarray(tcbtab, new_tcbtabsize, sizeof(tcbtab[0])); + while (tcbtabsize < new_tcbtabsize) + tcbtab[tcbtabsize++] = newtcbs++; } static struct tcb * @@ -1484,10 +1490,8 @@ get_os_release(void) static void ATTRIBUTE_NOINLINE init(int argc, char *argv[]) { - struct tcb *tcp; int c, i; int optF = 0; - unsigned int tcbi; struct sigaction sa; progname = argv[0] ? argv[0] : "strace"; @@ -1503,13 +1507,6 @@ init(int argc, char *argv[]) os_release = get_os_release(); - /* Allocate the initial tcbtab. */ - tcbtabsize = argc; /* Surely enough for all -p args. */ - tcbtab = xcalloc(tcbtabsize, sizeof(tcbtab[0])); - tcp = xcalloc(tcbtabsize, sizeof(*tcp)); - for (tcbi = 0; tcbi < tcbtabsize; tcbi++) - tcbtab[tcbi] = tcp++; - shared_log = stderr; set_sortby(DEFAULT_SORTBY); set_personality(DEFAULT_PERSONALITY); -- 2.40.0