From 4b5b548c9fedd5e6d920639e42ea8e5f473c4de3 Mon Sep 17 00:00:00 2001 From: "Fernando J. V. da Silva" Date: Fri, 6 Dec 2013 18:04:10 +0100 Subject: Fix BZ #15089: malloc_trim always trim for large padding. --- malloc/malloc.c | 68 +++++++++++++++++++++++++++++---------------------------- 1 file changed, 35 insertions(+), 33 deletions(-) (limited to 'malloc') diff --git a/malloc/malloc.c b/malloc/malloc.c index 8977687f8c..b3353bd0a3 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -2709,52 +2709,54 @@ static int systrim(size_t pad, mstate av) char* current_brk; /* address returned by pre-check sbrk call */ char* new_brk; /* address returned by post-check sbrk call */ size_t pagesz; + long top_area; pagesz = GLRO(dl_pagesize); top_size = chunksize(av->top); + top_area = top_size - MINSIZE - 1; + if (top_area <= pad) + return 0; + /* Release in pagesize units, keeping at least one page */ - extra = (top_size - pad - MINSIZE - 1) & ~(pagesz - 1); + extra = (top_area - pad) & ~(pagesz - 1); - if (extra > 0) { + /* + Only proceed if end of memory is where we last set it. + This avoids problems if there were foreign sbrk calls. + */ + current_brk = (char*)(MORECORE(0)); + if (current_brk == (char*)(av->top) + top_size) { /* - Only proceed if end of memory is where we last set it. - This avoids problems if there were foreign sbrk calls. + Attempt to release memory. We ignore MORECORE return value, + and instead call again to find out where new end of memory is. + This avoids problems if first call releases less than we asked, + of if failure somehow altered brk value. (We could still + encounter problems if it altered brk in some very bad way, + but the only thing we can do is adjust anyway, which will cause + some downstream failure.) */ - current_brk = (char*)(MORECORE(0)); - if (current_brk == (char*)(av->top) + top_size) { - - /* - Attempt to release memory. We ignore MORECORE return value, - and instead call again to find out where new end of memory is. - This avoids problems if first call releases less than we asked, - of if failure somehow altered brk value. (We could still - encounter problems if it altered brk in some very bad way, - but the only thing we can do is adjust anyway, which will cause - some downstream failure.) - */ - MORECORE(-extra); - /* Call the `morecore' hook if necessary. */ - void (*hook) (void) = force_reg (__after_morecore_hook); - if (__builtin_expect (hook != NULL, 0)) - (*hook) (); - new_brk = (char*)(MORECORE(0)); + MORECORE(-extra); + /* Call the `morecore' hook if necessary. */ + void (*hook) (void) = force_reg (__after_morecore_hook); + if (__builtin_expect (hook != NULL, 0)) + (*hook) (); + new_brk = (char*)(MORECORE(0)); - LIBC_PROBE (memory_sbrk_less, 2, new_brk, extra); + LIBC_PROBE (memory_sbrk_less, 2, new_brk, extra); - if (new_brk != (char*)MORECORE_FAILURE) { - released = (long)(current_brk - new_brk); + if (new_brk != (char*)MORECORE_FAILURE) { + released = (long)(current_brk - new_brk); - if (released != 0) { - /* Success. Adjust top. */ - av->system_mem -= released; - set_head(av->top, (top_size - released) | PREV_INUSE); - check_malloc_state(av); - return 1; - } - } + if (released != 0) { + /* Success. Adjust top. */ + av->system_mem -= released; + set_head(av->top, (top_size - released) | PREV_INUSE); + check_malloc_state(av); + return 1; + } } } return 0; -- cgit 1.4.1