Date: Fri, 16 Jun 2000 14:18:15 +0000 From: Joy Ganguly <joy@niksun.com> To: freebsd-hackers <freebsd-hackers@freeBSD.org> Subject: mmap and file writes...??? Message-ID: <394A3727.1FEC441E@falcon.niksun.com>
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hi all, i have a question regarding mmap and file write. a file is mmap'ed and data is written into the mapped region. now the same region is written. (as shown below) buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); . . /* some data put in buf */ . write(fd, buf, len); now does this lead to unnecessary copies?? more specifically what happens if two virtual addresses point to the same physical address and data is copied from one to the other. thanx in advance joy To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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