Date: Sat, 27 Mar 2004 14:28:05 -0600 From: Alan Cox <alc@cs.rice.edu> To: Mike Silbersack <silby@silby.com> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern subr_param.c sys_pipe.c src/sys/sys pipe.h Message-ID: <20040327202805.GU19961@cs.rice.edu> In-Reply-To: <20040327140454.H3199@odysseus.silby.com> References: <200403271950.i2RJoN9P033780@repoman.freebsd.org> <20040327140454.H3199@odysseus.silby.com>
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On Sat, Mar 27, 2004 at 02:05:56PM -0600, Mike Silbersack wrote: > > On Sat, 27 Mar 2004, Alan Cox wrote: > > > Log: > > Revise the direct or optimized case to use uiomove_fromphys() by the reader > > instead of ephemeral mappings using pmap_qenter() by the writer. The > > writer is still, however, responsible for wiring the pages, just not > > mapping them. Consequently, the allocation of KVA for the direct case is > > unnecessary. Remove it and the sysctls limiting it, i.e., > > kern.ipc.maxpipekvawired and kern.ipc.amountpipekvawired. The number > > of temporarily wired pages is still, however, limited by > > kern.ipc.maxpipekva. > > The best advantage of this change is that the workings of direct mapped > pipes make much more sense to those of us who are not VM experts. :) > I hope this also serves to motivate people to work on eliminating the buffer map. Consider uiomove_fromphys() as my contribution to that effort. :-) Alan
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