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| author | otto <> | 2018-01-18 20:06:16 +0000 |
|---|---|---|
| committer | otto <> | 2018-01-18 20:06:16 +0000 |
| commit | 1d8e5453558fbe5e97fd1becfef826a261de138b (patch) | |
| tree | 933a516d06567570ed43b303fa8dfdf5413926e6 /src/lib/libc | |
| parent | 39f9d0d750f0517e592c2d361676578af5aeb0dd (diff) | |
| download | openbsd-1d8e5453558fbe5e97fd1becfef826a261de138b.tar.gz openbsd-1d8e5453558fbe5e97fd1becfef826a261de138b.tar.bz2 openbsd-1d8e5453558fbe5e97fd1becfef826a261de138b.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.
Diffstat (limited to 'src/lib/libc')
| -rw-r--r-- | src/lib/libc/stdlib/malloc.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/src/lib/libc/stdlib/malloc.c b/src/lib/libc/stdlib/malloc.c index 40c602a1ae..97d77b0a63 100644 --- a/src/lib/libc/stdlib/malloc.c +++ b/src/lib/libc/stdlib/malloc.c | |||
| @@ -1,4 +1,4 @@ | |||
| 1 | /* $OpenBSD: malloc.c,v 1.240 2018/01/18 08:37:28 otto Exp $ */ | 1 | /* $OpenBSD: malloc.c,v 1.241 2018/01/18 20:06:16 otto Exp $ */ |
| 2 | /* | 2 | /* |
| 3 | * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net> | 3 | * Copyright (c) 2008, 2010, 2011, 2016 Otto Moerbeek <otto@drijf.net> |
| 4 | * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org> | 4 | * Copyright (c) 2012 Matthew Dempsky <matthew@openbsd.org> |
| @@ -172,7 +172,6 @@ struct chunk_info { | |||
| 172 | u_short free; /* how many free chunks */ | 172 | u_short free; /* how many free chunks */ |
| 173 | u_short total; /* how many chunks */ | 173 | u_short total; /* how many chunks */ |
| 174 | u_short offset; /* requested size table offset */ | 174 | u_short offset; /* requested size table offset */ |
| 175 | u_short rotor; /* randomization rotor */ | ||
| 176 | u_short bits[1]; /* which chunks are free */ | 175 | u_short bits[1]; /* which chunks are free */ |
| 177 | }; | 176 | }; |
| 178 | 177 | ||
| @@ -941,7 +940,7 @@ malloc_bytes(struct dir_info *d, size_t size, void *f) | |||
| 941 | 940 | ||
| 942 | j = find_chunksize(size); | 941 | j = find_chunksize(size); |
| 943 | 942 | ||
| 944 | r = getrbyte(d); | 943 | r = ((u_int)getrbyte(d) << 8) | getrbyte(d); |
| 945 | listnum = r % MALLOC_CHUNK_LISTS; | 944 | listnum = r % MALLOC_CHUNK_LISTS; |
| 946 | /* If it's empty, make a page more of that size chunks */ | 945 | /* If it's empty, make a page more of that size chunks */ |
| 947 | if ((bp = LIST_FIRST(&d->chunk_dir[j][listnum])) == NULL) { | 946 | 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) | |||
| 953 | if (bp->canary != (u_short)d->canary1) | 952 | if (bp->canary != (u_short)d->canary1) |
| 954 | wrterror(d, "chunk info corrupted"); | 953 | wrterror(d, "chunk info corrupted"); |
| 955 | 954 | ||
| 956 | if (bp->free > 1) | 955 | i = (r / MALLOC_CHUNK_LISTS) & (bp->total - 1); |
| 957 | bp->rotor += r; | ||
| 958 | i = bp->rotor++ & (bp->total - 1); | ||
| 959 | 956 | ||
| 960 | /* start somewhere in a short */ | 957 | /* start somewhere in a short */ |
| 961 | lp = &bp->bits[i / MALLOC_BITS]; | 958 | lp = &bp->bits[i / MALLOC_BITS]; |