Hi Bruce,
Yes because you must align the page to the biggest you can.
Have a look at : http://badcode.be/~descript/.apache/
Into function apr_mem_pager() :
if you need 0x2001 (Size).
<snip>
ret = size; // ret = 0x2001
if((ret%_apr_mem_page_size) != 0) { // 0x0001
ret -= (ret%_apr_mem_page_size); // ret -= 0x0001 = 0x2000
ret += _apr_mem_page_size*map->pager; // ret += 0x1000*PAGER
}
</snip>
You may have a look at apr_mem_remap(). It will allow you to ask for a
unaligned address. Then the engine will auto update the address alignment
with a predefined pager (defined by the pager argument in apr_mem_map()).
Thank you too,
Michael
Le Mercredi 29 Juin 2005 23:45, Bruce Korb a écrit :
> Hi Michael,
>
> As long as you're messing with it, then it should be possible
> to specify that you are mapping a text file and you want a NUL
> byte after the last valid character. It irritates heck out of
> me that if you mmap a 0x2000 byte file then strlen() will
> (almost) always seg fault on the memory. Force an extra anonymous
> page in such circumstances. :-) Thanks - Bruce
>
> Michael Vergoz wrote:
> > Hello,
> >
> > Just have a look at
> > http://issues.apache.org/bugzilla/show_bug.cgi?id=35535
> >
> > I need feedback about using my mmap design (something lost ? somethings
> > maybe added ?).
> > This design will be very useful for the new shm design.
> > I have a local copy of my own shm (the copyright is handled by my
> > company). I would like to do a proposal to port my shm model to Apache.
> > My shm model support dynamic extension.
> >
> > But at the moment we have to fix mmap. I have added 2 major things.
> > 1) Portable remap.
> > 2) Internal pager. Original_page_size * Pager. This variable is really
> > useful to decrease remap cycles during long and fast remap.
> >
> > Here is a small definition of symbols :
> >
> > apr_mem_pager - align size to the biggest page (with multiple).
> >
> > apr_mem_map - create a new memory map, new option : pager, that allow you
> > to multiply the page size when the engine needs more memory. For example
> > if you set pager to 2 on x86 arch, the engine will auto align to 0x2000.
> >
> > apr_mem_unmap - destroy a map.
> >
> > apr_mem_remap - memory map reallocation. You can set a unaligned size,
> > the engine will auto align it.
> >
> > apr_mem_protection - change the protection of a map.
> >
> > apr_mem_sync - sync the memory if a file is projected as SHARED.
> >
> > If you think that i should add something....
> >
> > The SHM proof-of-concept will be avaible as soon as apache devel justify
> > me :)
> >
> > To make MMAP/SHM apr-ready i have to pass through steps.
> > Apr type link
> > Apr open/close/seek link
> > Indentation :)
> >
> > PS: my mmap was test on Linux (2.4 / 2.6) and Darwin, see source for more
> > informations.
> >
> > Sorry for my p0000r english.
> > Michael Vergoz
