Re: BPF packet pagesize limit

2017-11-21 Thread Ryan Stone
Do not allocate MJUM9BYTES clusters under any circumstances. Trying to allocate them when the system is under memory pressure is enormously expensive and stands a good chance of livelocking the system if you try to allocate too many too quickly, even when allocating with M_NOWAIT. Honestly, suppo

Re: BPF packet pagesize limit

2017-11-21 Thread Kristof Provost
On 21 Nov 2017, at 17:14, Catalin Salgau wrote: Actually m_getm2() will always produce a chain for a size larger than the page size, due to m_getjcl() being called with MJUMPAGESIZE every time a large buffer is requested. The function could probably be called with MJUM9BYTES in this case, but t

Re: BPF packet pagesize limit

2017-11-21 Thread Catalin Salgau
On 20/11/2017 11:26 pm, Kristof Provost wrote: > On 19 Nov 2017, at 19:49, Catalin Salgau wrote: > > I'm trying to address the limitation in (upstream) net/vblade that was > brought up in > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=205164 > This is related to writes large

Re: BPF packet pagesize limit

2017-11-20 Thread Kristof Provost
On 19 Nov 2017, at 19:49, Catalin Salgau wrote: I'm trying to address the limitation in (upstream) net/vblade that was brought up in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=205164 This is related to writes larger than hw.pagesize but smaller than the configured MTU with BPF. I traced th

BPF packet pagesize limit

2017-11-19 Thread Catalin Salgau
Hello, I'm trying to address the limitation in (upstream) net/vblade that was brought up in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=205164 This is related to writes larger than hw.pagesize but smaller than the configured MTU with BPF. I traced this to sys/net/bpf.c where calls to bpfwrit