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SubjectRe: 2.6.8.1-mm4
On Sun, Aug 22, 2004 at 01:34:02AM -0700, Andrew Morton wrote:
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.8.1/2.6.8.1-mm4/
> - Added the kexec code. Again. This was in -mm a year or so ago but didn't
> make it.
> - This kernel has an x86 patch which alters the copy_*_user() functions so
> they will return -EFAULT on a fault rather than the number of bytes which
> remain to be copied. This is a bit of an experiment, because this seems to
> be the preferred API for those functions. It's a see-what-breaks thing.
> And things will break. If weird behaviour is observed, please revert
> usercopy-return-EFAULT.patch and send a report.

task_vsize() doesn't need mm->mmap_sem for the CONFIG_MMU case; the
semaphore doesn't prevent mm->total_vm from going stale or getting
inconsistent with other numbers regardless. Also, KSTK_EIP() and
KSTK_ESP() don't want or need protection from mm->mmap_sem either. So
this pushes mm->mmap_sem to task_vsize() in the CONFIG_MMU=n task_vsize().

Also, hoist the prototype of task_vsize() into proc_fs.h

The net result of this is a small speedup of procps for CONFIG_MMU.


Index: mm4-2.6.8.1/fs/proc/array.c
===================================================================
--- mm4-2.6.8.1.orig/fs/proc/array.c 2004-08-23 10:16:52.126977417 -0700
+++ mm4-2.6.8.1/fs/proc/array.c 2004-08-23 10:20:24.268576381 -0700
@@ -300,7 +300,6 @@
return buffer - orig;
}

-extern unsigned long task_vsize(struct mm_struct *);
int proc_pid_stat(struct task_struct *task, char * buffer)
{
unsigned long vsize, eip, esp, wchan;
@@ -320,11 +319,9 @@
vsize = eip = esp = 0;
mm = get_task_mm(task);
if (mm) {
- down_read(&mm->mmap_sem);
vsize = task_vsize(mm);
eip = KSTK_EIP(task);
esp = KSTK_ESP(task);
- up_read(&mm->mmap_sem);
}

get_task_comm(tcomm, task);
Index: mm4-2.6.8.1/fs/proc/task_nommu.c
===================================================================
--- mm4-2.6.8.1.orig/fs/proc/task_nommu.c 2004-08-14 03:55:33.000000000 -0700
+++ mm4-2.6.8.1/fs/proc/task_nommu.c 2004-08-23 10:21:10.930685184 -0700
@@ -68,11 +68,12 @@
struct mm_tblock_struct *tbp;
unsigned long vsize = 0;

+ down_read(&mm->mmap_sem);
for (tbp = &mm->context.tblock; tbp; tbp = tbp->next) {
if (tbp->rblock)
vsize += kobjsize(tbp->rblock->kblock);
}
-
+ up_read(&mm->mmap_sem);
return vsize;
}

Index: mm4-2.6.8.1/include/linux/proc_fs.h
===================================================================
--- mm4-2.6.8.1.orig/include/linux/proc_fs.h 2004-08-14 03:56:25.000000000 -0700
+++ mm4-2.6.8.1/include/linux/proc_fs.h 2004-08-23 10:22:38.627949735 -0700
@@ -90,6 +90,7 @@
struct dentry *proc_pid_unhash(struct task_struct *p);
void proc_pid_flush(struct dentry *proc_dentry);
int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir);
+unsigned long task_vsize(struct mm_struct *);

extern struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
struct proc_dir_entry *parent);
-
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