Date: Fri, 25 Jan 2002 04:07:26 -0600 (CST) From: Hyong-Youb Kim <hykim@cs.rice.edu> To: <freebsd-hackers@FreeBSD.org> Subject: vm and vfs_bio Message-ID: <Pine.GSO.4.33.0201250332100.15122-100000@colorado.cs.rice.edu>
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From what I have gathered from 4.4bsd book and 4.3 freebsd source code, struct buf and various b* (read, write etc) functions implement the file cache. I am wondering where the physical pages that struct buf has references to reside in the vm map. It seems its virtual addresses are allocated using buffer_map. Well my real question would be, does the vm maintain a file cache independent of the file cache using struct buf? And this is quite a different question but I will ask here. When a user does a read (followed by open) on a file, the kernel must allocate vnode corresponding to that file right? Assuming the file is not memory-mapped by any other process, would the vnode still have a valid v_object field? Ahh I am confused. Thanks in advance. John To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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