On Tuesday, March 12, 2013 12:33:04 pm Andre Oppermann wrote: > On 12.03.2013 16:50, Gleb Smirnoff wrote: > > On Tue, Mar 12, 2013 at 04:31:05PM +0100, Andre Oppermann wrote: > > A> > If you are concerned about using jumbos that are > PAGE_SIZE, then I > > can > > A> > extend API in my patch. ... done. > > A> > > > A> > Patch attached. > > A> > > > A> > The NFS code itself guarantees that it won't request > than MCLBYTES, > > A> > so using bare m_get2() here is safe. I can add flag there later for > > A> > clarity. > > A> > > A> Using PAGE_SIZE clusters is perfectly fine and no flag to prevent that > > A> is necessary. In fact we're doing it for years on socket writes without > > A> complaints (through m_getm2()). > > > > mbuf usage isn't limited to sockets. There is some code that right now > > utilizes > > only mbufs and standard clusters, netipsec for example. > > Yes, I understand that. > > > I'd like to remove a lot of handmade mbuf allocating, in different places in > > kernel and this can be done with M_NOJUMBO flag. I don't have time to dig > > more > > deep into large chunks of code trying to understand whether it is possible > > to > > convert them into using PAGE_SIZE clusters or not, I just want to reduce > > amount of pasted hand allocating. > > Reducing the amount of hand allocation is very good. > > > We have very common case when we allocate either mbuf or mbuf + cluster, > > depending on size. Everywhere this is made by hand, but can be substituted > > with m_get2(len, ..., M_NOJUMBO); > > I guess what I'm trying to say is that not wanting jumbo > PAGE_SIZE is > normal and shouldn't be specified all the time. > > This makes the API look like this: > > m_get2(len, ..., 0); /* w/o flags I get at most MJUMPAGESIZE */ > > If someone really, really, really knows what he is doing he can say > he wants jumbo > PAGE_SIZE returned with M_JUMBOOK or such. However > IMHO even that shouldn't be offered and m_getm2() should be used for > a chain.
I agree, large clusters should require opting-in, they should not be provided by default (if at all as Andre suggests). -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"