diff options
| -rw-r--r-- | lib/libc/sys/mmap.2 | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/lib/libc/sys/mmap.2 b/lib/libc/sys/mmap.2 index d70d871..32fcb44 100644 --- a/lib/libc/sys/mmap.2 +++ b/lib/libc/sys/mmap.2 @@ -213,13 +213,13 @@ was specified and insufficient memory was available. .Sh BUGS .Ar len -is limit to 2GB. Mmapping slightly more than 2GB doesn't work, but -mapping a window of size (filesize % 2GB) for file sizes of slightly -less than 2G, 4GB, 6GB and 8GB. +is limited to 2GB. Mmapping slightly more than 2GB doesn't work, but +it is possible to map a window of size (filesize % 2GB) for file sizes +of slightly less than 2G, 4GB, 6GB and 8GB. The limit is imposed for a variety of reasons. Most of them have to do with FreeBSD not wanting to use 64 bit offsets in the VM system due to -the extreme performance penalty. So FreeBSD use 32bit page indexes and +the extreme performance penalty. So FreeBSD uses 32bit page indexes and this gives FreeBSD a maximum of 8TB filesizes. It's actually bugs in the filesystem code that causes the limit to be further restricted to 1TB (loss of precision when doing blockno calculations). |
