[BUG?]Data key in /proc/allocinfo is a multiset

[David Wang]

Just start a new thread for this[1].
There are duplications in /proc/allocinfo where same [file:line]
shows up several times:

=======================
           0        0 ./include/crypto/kpp.h:185 func:kpp_request_alloc 
           0        0 ./include/crypto/kpp.h:185 func:kpp_request_alloc 
=======================
           0        0 ./include/net/tcp.h:2548 func:tcp_v4_save_options 
           0        0 ./include/net/tcp.h:2548 func:tcp_v4_save_options 
=======================
           0        0 drivers/iommu/amd/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/amd/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/amd/../iommu-pages.h:94 func:iommu_alloc_pages_node 
=======================
           0        0 drivers/iommu/intel/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/intel/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/intel/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/intel/../iommu-pages.h:94 func:iommu_alloc_pages_node 
           0        0 drivers/iommu/intel/../iommu-pages.h:94 func:iommu_alloc_pages_node 
...

The duplication make parsing tools a little bit more complicated:
the numbers need to be added up, group by key
       81920       20 drivers/iommu/amd/../iommu-pages.h:94 func:iommu_alloc_pages_node 20 
     1441792      352 drivers/iommu/amd/../iommu-pages.h:94 func:iommu_alloc_pages_node 352

The script for checking:
```
#!/bin/env python
def fetch():
    r = {}
    with open("/proc/allocinfo") as f:
        for l in f:
            f = l.strip().split()[2]
            if f not in r: r[f]=[]
            r[f].append(l)
    keys = []
    for f, ls in r.items():
        if len(ls) > 1: keys.append(f)
    keys.sort()
    for f in keys:
        print "======================="
        for l in r[f]: print l,

fetch()
```

Thanks
David

[1]. https://lore.kernel.org/lkml/531adbba.b537.196b0868a8c.Coremail.00107082@xxxxxxx/