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Fix BZ #15089: malloc_trim always trim for large padding.

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This commit is contained in:
Fernando J. V. da Silva
2013-12-06 18:04:10 +01:00
committed by Ondřej Bílka
parent 0a3ac0aabf
commit 4b5b548c9f
3 changed files with 51 additions and 44 deletions
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70
malloc/malloc.c
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@ -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);
/* Release in pagesize units, keeping at least one page */
extra = (top_size - pad - MINSIZE - 1) & ~(pagesz - 1);
top_area = top_size - MINSIZE - 1;
if (top_area <= pad)
return 0;
if (extra > 0) {
/* Release in pagesize units, keeping at least one page */
extra = (top_area - pad) & ~(pagesz - 1);
/*
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;