Messages in this thread | | | Date | Wed, 14 Jan 2009 14:08:35 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: [RFC][PATCH] don't show pgoff of vma if vma is pure ANON (was Re: mmotm 2009-01-12-16-53 uploaded) |
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On Wed, 14 Jan 2009, KAMEZAWA Hiroyuki wrote: > Hmm, is this brutal ? > > == > Recently, it's argued that what proc/pid/maps shows is ugly when a > 32bit binary runs on 64bit host. > > /proc/pid/maps outputs vma's pgoff member but vma->pgoff is of no use > information is the vma is for ANON. > By this patch, /proc/pid/maps shows just 0 if no file backing store. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> > ---
Brutal, but sensible enough: revert to how things looked before we ever starting putting vm_pgoff to work on anonymous areas.
I slightly regret losing that visible clue to whether an anonymous vma has ever been mremap moved. But have I ever actually used that info? No, never.
I presume you test !vma->vm_file so the lines fit in, fair enough. But I think you'll find checkpatch.pl protests at "(!vma->vm_file)?"
I dislike its decisions on the punctuation of the ternary operator - perhaps even more than Andrew dislikes the operator itself! Do we write a space before a question mark? no: nor before a colon; but I also dislike getting into checkpatch.pl arguments!
While you're there, I'd also be inclined to make task_nommu.c use the same loff_t cast as task_mmu.c is using.
Hugh
> Index: mmotm-2.6.29-Jan13/fs/proc/task_mmu.c > =================================================================== > --- mmotm-2.6.29-Jan13.orig/fs/proc/task_mmu.c > +++ mmotm-2.6.29-Jan13/fs/proc/task_mmu.c > @@ -220,7 +220,8 @@ static void show_map_vma(struct seq_file > flags & VM_WRITE ? 'w' : '-', > flags & VM_EXEC ? 'x' : '-', > flags & VM_MAYSHARE ? 's' : 'p', > - ((loff_t)vma->vm_pgoff) << PAGE_SHIFT, > + (!vma->vm_file)? 0 : > + ((loff_t)vma->vm_pgoff) << PAGE_SHIFT, > MAJOR(dev), MINOR(dev), ino, &len); > > /* > Index: mmotm-2.6.29-Jan13/fs/proc/task_nommu.c > =================================================================== > --- mmotm-2.6.29-Jan13.orig/fs/proc/task_nommu.c > +++ mmotm-2.6.29-Jan13/fs/proc/task_nommu.c > @@ -143,7 +143,8 @@ static int nommu_vma_show(struct seq_fil > flags & VM_WRITE ? 'w' : '-', > flags & VM_EXEC ? 'x' : '-', > flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p', > - (unsigned long long) vma->vm_pgoff << PAGE_SHIFT, > + (!vma->vm_file) ? 0 : > + (unsigned long long) vma->vm_pgoff << PAGE_SHIFT, > MAJOR(dev), MINOR(dev), ino, &len); > > if (file) { >
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