Re: [hackers] Re: Setting memory allocators for library functions.

[Tony Finch]

Lyndon Nerenberg <[EMAIL PROTECTED]> wrote:
>
>If the information in the data segment is going to be updated then
>you have to have writable backing store. If, however, that data
>is never going to be changed, it should be declared in the program
>as read-only data. The kernel VM system should not be working around
>applications that don't declare their data arena correctly.

In most cases it is impossible to declare the data read-only because
it originally had to be read-write and you can't change its attributes
later. This is always the case for malloc(). Many applications do a
load of initialization that requires read-write memory then never
write to that memory again; when they fork the OS still has to account
for that memory twice even if it is going to be immediately discarded
by an exec(). An even more exaggerated example is Apache which forks a
load of times then hangs around for ages.

Tony.
-- 
f.a.n.finch    [EMAIL PROTECTED]    [EMAIL PROTECTED]
MALIN: NORTHEAST 7 TO SEVERE GALE 9, OCCASIONALLY STORM 10 IN SOUTHEAST AT
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