[lkml]   [2001]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: how mmap() works?

On 03.30 Jerry Hong wrote:
> Hi,
> mmap() creates a mmaped memory associated with a
> physical file. If a process updates the mmaped memory,
> Linux will updates the file "automatically". If this
> is the case, why do we need msync()? If this is not

Where did you heard that ?

man mmap(2):
MAP_SHARED Share this mapping with all other processes
that map this object. Storing to the region is
equivalent to writing to the file. The file
may not actually be updated until msync(2) or
munmap(2) are called.
man msync(2):
msync flushes changes made to the in-core copy of a file
that was mapped into memory using mmap(2) back to disk.
Without use of this call there is no guarantee that
changes are written back before munmap(2) is called. To

J.A. Magallon # Let the source # be with you, Luke...

Linux werewolf 2.4.2-ac28 #1 SMP Thu Mar 29 16:41:17 CEST 2001 i686

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:18    [W:0.064 / U:2.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site