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mmap.c (backtrace_free): If freeing a large aligned block of memory, call munmap rather than holding onto it.

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* mmap.c (backtrace_free): If freeing a large aligned block of
	memory, call munmap rather than holding onto it.
	(backtrace_vector_grow): When growing a vector, double the number
	of pages requested.  When releasing the old version of a grown
	vector, pass the correct size to backtrace_free.

From-SVN: r210256
This commit is contained in:
Ian Lance Taylor 2014-05-09 05:01:08 +00:00 committed by Ian Lance Taylor
parent 0600049c86
commit d573fd89a5
2 changed files with 34 additions and 2 deletions
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8
libbacktrace/ChangeLog
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@ -1,3 +1,11 @@
2014-05-08 Ian Lance Taylor <iant@google.com>
* mmap.c (backtrace_free): If freeing a large aligned block of
memory, call munmap rather than holding onto it.
(backtrace_vector_grow): When growing a vector, double the number
of pages requested. When releasing the old version of a grown
vector, pass the correct size to backtrace_free.
2014-03-07 Ian Lance Taylor <iant@google.com>
* sort.c (backtrace_qsort): Use middle element as pivot.

28
libbacktrace/mmap.c
View File

@ -164,6 +164,26 @@ backtrace_free (struct backtrace_state *state, void *addr, size_t size,
{
int locked;
/* If we are freeing a large aligned block, just release it back to
the system. This case arises when growing a vector for a large
binary with lots of debug info. Calling munmap here may cause us
to call mmap again if there is also a large shared library; we
just live with that. */
if (size >= 16 * 4096)
{
size_t pagesize;
pagesize = getpagesize ();
if (((uintptr_t) addr & (pagesize - 1)) == 0
&& (size & (pagesize - 1)) == 0)
{
/* If munmap fails for some reason, just add the block to
the freelist. */
if (munmap (addr, size) == 0)
return;
}
}
/* If we can acquire the lock, add the new space to the free list.
If we can't acquire the lock, just leak the memory.
__sync_lock_test_and_set returns the old state of the lock, so we
@ -209,14 +229,18 @@ backtrace_vector_grow (struct backtrace_state *state,size_t size,
alc = pagesize;
}
else
alc = (alc + pagesize - 1) & ~ (pagesize - 1);
{
alc *= 2;
alc = (alc + pagesize - 1) & ~ (pagesize - 1);
}
base = backtrace_alloc (state, alc, error_callback, data);
if (base == NULL)
return NULL;
if (vec->base != NULL)
{
memcpy (base, vec->base, vec->size);
backtrace_free (state, vec->base, vec->alc, error_callback, data);
backtrace_free (state, vec->base, vec->size + vec->alc,
error_callback, data);
}
vec->base = base;
vec->alc = alc - vec->size;