2006-02-24 15:07:50

by Michael Buesch

[permalink] [raw]
Subject: [PATCH] Uninline sys_mmap common code (reduce binary size)

This patch removes the inlinining of the new vs old mmap system
call common code.
This reduces the size of the resulting vmlinux for defconfig as follows:

mb@pc1:~/develop/git/linux-2.6$ size vmlinux.mmap*
text data bss dec hex filename
3303749 521524 186564 4011837 3d373d vmlinux.mmapinline
3303557 521524 186564 4011645 3d367d vmlinux.mmapnoinline

The new sys_mmap2() has also one function call overhead removed, now.
(probably it was already optimized to a jmp before, but anyway...)


diff --git a/arch/i386/kernel/sys_i386.c b/arch/i386/kernel/sys_i386.c
index a4a6197..8fdb1fb 100644
--- a/arch/i386/kernel/sys_i386.c
+++ b/arch/i386/kernel/sys_i386.c
@@ -40,14 +40,13 @@ asmlinkage int sys_pipe(unsigned long __
return error;
}

-/* common code for old and new mmaps */
-static inline long do_mmap2(
- unsigned long addr, unsigned long len,
- unsigned long prot, unsigned long flags,
- unsigned long fd, unsigned long pgoff)
+asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
+ unsigned long prot, unsigned long flags,
+ unsigned long fd, unsigned long pgoff)
{
int error = -EBADF;
- struct file * file = NULL;
+ struct file *file = NULL;
+ struct mm_struct *mm = current->mm;

flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
if (!(flags & MAP_ANONYMOUS)) {
@@ -56,9 +55,9 @@ static inline long do_mmap2(
goto out;
}

- down_write(&current->mm->mmap_sem);
+ down_write(&mm->mmap_sem);
error = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
- up_write(&current->mm->mmap_sem);
+ up_write(&mm->mmap_sem);

if (file)
fput(file);
@@ -66,13 +65,6 @@ out:
return error;
}

-asmlinkage long sys_mmap2(unsigned long addr, unsigned long len,
- unsigned long prot, unsigned long flags,
- unsigned long fd, unsigned long pgoff)
-{
- return do_mmap2(addr, len, prot, flags, fd, pgoff);
-}
-
/*
* Perform the select(nd, in, out, ex, tv) and mmap() system
* calls. Linux/i386 didn't use to be able to handle more than
@@ -101,7 +93,8 @@ asmlinkage int old_mmap(struct mmap_arg_
if (a.offset & ~PAGE_MASK)
goto out;

- err = do_mmap2(a.addr, a.len, a.prot, a.flags, a.fd, a.offset >> PAGE_SHIFT);
+ err = sys_mmap2(a.addr, a.len, a.prot, a.flags,
+ a.fd, a.offset >> PAGE_SHIFT);
out:
return err;
}


--
Greetings Michael.


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