Date: Tue, 29 Jun 2004 15:57:05 +0000 (UTC) From: Peter Wemm <peter@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/i386/i386 pmap.c src/sys/i386/include pmap.h Message-ID: <200406291557.i5TFv5rm097109@repoman.freebsd.org>
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peter 2004-06-29 15:57:05 UTC FreeBSD src repository Modified files: sys/i386/i386 pmap.c sys/i386/include pmap.h Log: Reduce the size of pv entries by 15%. This saves 1MB of KVA for mapping pv entries per 1GB of user virtual memory. (eg: if we had 1GB file was mmaped into 30 processes, that would theoretically reduce the KVA demand by 30MB for pv entries. In reality though, we limit pv entries so we don't have that many at once.) We used to store the vm_page_t for the page table page. But we recently had the pa of the ptp, or can calculate it fairly quickly. If we wanted to avoid the shift/mask operation in pmap_pde(), we could recover the pa but that means we have to store it for a while. This does not measurably change performance. Suggested by: alc Tested by: alc Revision Changes Path 1.479 +15 -16 src/sys/i386/i386/pmap.c 1.112 +0 -1 src/sys/i386/include/pmap.h
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