diff options
| author |   otto <otto@openbsd.org> | 2018-01-18 20:06:16 +0000 |
|---|---|---|
| committer | otto <otto@openbsd.org> | 2018-01-18 20:06:16 +0000 |
| commit | 727b47853a4df1f9473506558d7ed9fb8f703924 (patch) | |
| tree | 7a1616641fb2700670622a1fdf7f7809e96d3318 | |
| parent | Sorry, the PIC macros cannot reach to .rodata.... (diff) | |
| download | wireguard-openbsd-727b47853a4df1f9473506558d7ed9fb8f703924.tar.xz wireguard-openbsd-727b47853a4df1f9473506558d7ed9fb8f703924.zip | |
Zap the rotor, it was a wrong idea. Cluebat applied by kshe who
came also up with this diff. Simple, no bias and benchmarks show the extra
random calls disappear in te measurement noise.
| -rw-r--r-- | lib/libc/stdlib/malloc.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/lib/libc/stdlib/malloc.c b/lib/libc/stdlib/malloc.c index 40c602a1aeb..97d77b0a631 100644 --- a/lib/libc/stdlib/malloc.c +++ b/lib/libc/stdlib/malloc.c @@ -1,4 +1,4 @@ -/* $OpenBSD: malloc.c,v 1.240 2018/01/18 08:37:28 otto Exp $ */ +/* $OpenBSD: malloc.c,v 1.241 2018/01/18 20:06:16 otto Exp $ */ /* * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net> * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org> @@ -172,7 +172,6 @@ struct chunk_info { u_short free; /* how many free chunks */ u_short total; /* how many chunks */ u_short offset; /* requested size table offset */ - u_short rotor; /* randomization rotor */ u_short bits[1]; /* which chunks are free */ }; @@ -941,7 +940,7 @@ malloc_bytes(struct dir_info *d, size_t size, void *f) j = find_chunksize(size); - r = getrbyte(d); + r = ((u_int)getrbyte(d) << 8) | getrbyte(d); listnum = r % MALLOC_CHUNK_LISTS; /* If it's empty, make a page more of that size chunks */ if ((bp = LIST_FIRST(&d->chunk_dir[j][listnum])) == NULL) { @@ -953,9 +952,7 @@ malloc_bytes(struct dir_info *d, size_t size, void *f) if (bp->canary != (u_short)d->canary1) wrterror(d, "chunk info corrupted"); - if (bp->free > 1) - bp->rotor += r; - i = bp->rotor++ & (bp->total - 1); + i = (r / MALLOC_CHUNK_LISTS) & (bp->total - 1); /* start somewhere in a short */ lp = &bp->bits[i / MALLOC_BITS]; |