only use memcpy realloc to shrink if an exact-sized free chunk exists master
authorRich Felker <dalias@aerifal.cx>
Tue, 16 Jun 2020 04:53:57 +0000 (00:53 -0400)
committerRich Felker <dalias@aerifal.cx>
Tue, 16 Jun 2020 04:58:22 +0000 (00:58 -0400)
commitfca7428c096066482d8c3f52450810288e27515c
tree985334c5d64519bbaa87a7502654718cd5bb577e
parentcb5babdc8d624a3e3e7bea0b4e28a677a2f2fc46
only use memcpy realloc to shrink if an exact-sized free chunk exists

otherwise, shrink in-place. as explained in the description of commit
3e16313f8fe2ed143ae0267fd79d63014c24779f, the split here is valid
without holding split_merge_lock because all chunks involved are in
the in-use state.
src/malloc/oldmalloc/malloc.c