i suggest you do a little before you ask any questions.
first, we never load a whole file into memory, second, it is hardly relevent to
vm struct
Sent from my HTC
- Reply message -
From: "horseriver"
To:
Subject: internel implemention of file operation
Date: Thu, Jan 3, 20
> Default read/write inerfaces does not move file's data to process address
space ?
Yes it does, in either case, user space memory has to be in process address
space. But Difference is in the access pattern. With read/write, you demand
for it explicitly through a system call, hence application is m
On Fri, Jan 11, 2013 at 12:39:26PM +0530, Rajat Sharma wrote:
> Default read/write inerfaces are better suited for sequential read/write
> within your program. Although you can seek to any location within the file,
> you still have overhead to issue system calls to get data. However mmap
> allows
Default read/write inerfaces are better suited for sequential read/write
within your program. Although you can seek to any location within the file,
you still have overhead to issue system calls to get data. However mmap
allows you to map a section of file into program address space. Now if your
ac
hi:
these two wayes of operating one file :
1.use open/write interface call .
2.mmap this file into memory , then access this memory area and do r/w .
what is the essential difference between this teo wayes?
thanks!
___
Kernelnewbies mailin
> in this vm_operations_struct , there are open/close functions , are
there necessary relations between file operations and this struct ?
well not really for open/close of vm_ops are of interest to filesystems,
but page fault handler and making page writable is where filesystem come
into picture.
On Thu, Jan 03, 2013 at 01:16:06PM +0530, Rajat Sharma wrote:
> > will it be maped with vm_area struct ?
> Yes if it is accessed via mmap system call.
you know that , in the struct vm_area_struct,there is a struct
vm_operations_struct * vm_ops;
in this vm_operations_struct , there are open/clos
unfortunately these are not the topic to digest in a mail, I recommend you
reading UTLK book (http://shop.oreilly.com/product/9780596005658.do).
Still...
> will it be maped with vm_area struct ?
Yes if it is accessed via mmap system call.
> what is the relation between page-cache and file operat
On Thu, Jan 03, 2013 at 12:48:01PM +0530, Rajat Sharma wrote:
> Never heard of page-cache?
will it be maped with vm_area struct ?
what is the relation between page-cache and file operation?
thanks!
>
>
> On Thu, Jan 3, 2013 at 12:29 PM, horseriver wrote:
>
> > hi:
> >
> > when one file is
Never heard of page-cache?
On Thu, Jan 3, 2013 at 12:29 PM, horseriver wrote:
> hi:
>
> when one file is opened , does its data be put into memory ? and all
> operation on this file
>
> will be implemented by operation on its mapping memory area ?
>
> thanks!
>
> __
hi:
when one file is opened , does its data be put into memory ? and all
operation on this file
will be implemented by operation on its mapping memory area ?
thanks!
___
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