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re PR other/68239 (libbacktrace allocation is sometimes very slow)

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PR other/68239
	* mmap.c (backtrace_free_locked): Don't put more than 16 entries
	on the free list.

From-SVN: r257039
This commit is contained in:
Ian Lance Taylor 2018-01-25 02:24:45 +00:00 • committed by Ian Lance Taylor
parent 533277ba75
commit 3fe3c7d749
2 changed files with 29 additions and 1 deletions
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6
libbacktrace/ChangeLog
View file

@ -1,3 +1,9 @@
2018-01-24 Ian Lance Taylor <iant@golang.org>
PR other/68239
* mmap.c (backtrace_free_locked): Don't put more than 16 entries
on the free list.
2018-01-19 Tony Reix <tony.reix@atos.net>
* xcoff.c (xcoff_incl_compare): New function.

24
libbacktrace/mmap.c
View file

@ -69,11 +69,33 @@ struct backtrace_freelist_struct
static void
backtrace_free_locked (struct backtrace_state *state, void *addr, size_t size)
{
/* Just leak small blocks. We don't have to be perfect. */
/* Just leak small blocks. We don't have to be perfect. Don't put
more than 16 entries on the free list, to avoid wasting time
searching when allocating a block. If we have more than 16
entries, leak the smallest entry. */
if (size >= sizeof (struct backtrace_freelist_struct))
{
size_t c;
struct backtrace_freelist_struct **ppsmall;
struct backtrace_freelist_struct **pp;
struct backtrace_freelist_struct *p;
c = 0;
ppsmall = NULL;
for (pp = &state->freelist; *pp != NULL; pp = &(*pp)->next)
{
if (ppsmall == NULL || (*pp)->size < (*ppsmall)->size)
ppsmall = pp;
++c;
}
if (c >= 16)
{
if (size <= (*ppsmall)->size)
return;
*ppsmall = (*ppsmall)->next;
}
p = (struct backtrace_freelist_struct *) addr;
p->next = state->freelist;
p->size = size;