Re: [PATCH v2 1/6] Documentation: filesystems: proc: update meminfo section

[David Hildenbrand <david@redhat.com>]

On 10.05.22 17:28, Johannes Weiner wrote:
> Add new entries. Minor corrections and cleanups.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
>  Documentation/filesystems/proc.rst | 155 ++++++++++++++++++-----------
>  1 file changed, 99 insertions(+), 56 deletions(-)
> 
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 061744c436d9..736ed384750c 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -942,56 +942,71 @@ can be substantial.  In many cases there are other means to find out
>  additional memory using subsystem specific interfaces, for instance
>  /proc/net/sockstat for TCP memory allocations.
>  
> -The following is from a 16GB PIII, which has highmem enabled.
> -You may not have all of these fields.
> +Example output. You may not have all of these fields.
>  
>  ::
>  
>      > cat /proc/meminfo
>  
> -    MemTotal:     16344972 kB
> -    MemFree:      13634064 kB
> -    MemAvailable: 14836172 kB
> -    Buffers:          3656 kB
> -    Cached:        1195708 kB
> -    SwapCached:          0 kB
> -    Active:         891636 kB
> -    Inactive:      1077224 kB
> -    HighTotal:    15597528 kB
> -    HighFree:     13629632 kB
> -    LowTotal:       747444 kB
> -    LowFree:          4432 kB
> -    SwapTotal:           0 kB
> -    SwapFree:            0 kB
> -    Dirty:             968 kB
> -    Writeback:           0 kB
> -    AnonPages:      861800 kB
> -    Mapped:         280372 kB
> -    Shmem:             644 kB
> -    KReclaimable:   168048 kB
> -    Slab:           284364 kB
> -    SReclaimable:   159856 kB
> -    SUnreclaim:     124508 kB
> -    PageTables:      24448 kB
> -    NFS_Unstable:        0 kB
> -    Bounce:              0 kB
> -    WritebackTmp:        0 kB
> -    CommitLimit:   7669796 kB
> -    Committed_AS:   100056 kB
> -    VmallocTotal:   112216 kB
> -    VmallocUsed:       428 kB
> -    VmallocChunk:   111088 kB
> -    Percpu:          62080 kB
> -    HardwareCorrupted:   0 kB
> -    AnonHugePages:   49152 kB
> -    ShmemHugePages:      0 kB
> -    ShmemPmdMapped:      0 kB
> +    MemTotal:       32858820 kB
> +    MemFree:        21001236 kB
> +    MemAvailable:   27214312 kB
> +    Buffers:          581092 kB
> +    Cached:          5587612 kB
> +    SwapCached:            0 kB
> +    Active:          3237152 kB
> +    Inactive:        7586256 kB
> +    Active(anon):      94064 kB
> +    Inactive(anon):  4570616 kB
> +    Active(file):    3143088 kB
> +    Inactive(file):  3015640 kB
> +    Unevictable:           0 kB
> +    Mlocked:               0 kB
> +    SwapTotal:             0 kB
> +    SwapFree:              0 kB
> +    Dirty:                12 kB
> +    Writeback:             0 kB
> +    AnonPages:       4654780 kB
> +    Mapped:           266244 kB
> +    Shmem:              9976 kB
> +    KReclaimable:     517708 kB
> +    Slab:             660044 kB
> +    SReclaimable:     517708 kB
> +    SUnreclaim:       142336 kB
> +    KernelStack:       11168 kB
> +    PageTables:        20540 kB
> +    NFS_Unstable:          0 kB
> +    Bounce:                0 kB
> +    WritebackTmp:          0 kB
> +    CommitLimit:    16429408 kB
> +    Committed_AS:    7715148 kB
> +    VmallocTotal:   34359738367 kB
> +    VmallocUsed:       40444 kB
> +    VmallocChunk:          0 kB
> +    Percpu:            29312 kB
> +    HardwareCorrupted:     0 kB
> +    AnonHugePages:   4149248 kB
> +    ShmemHugePages:        0 kB
> +    ShmemPmdMapped:        0 kB
> +    FileHugePages:         0 kB
> +    FilePmdMapped:         0 kB
> +    CmaTotal:              0 kB
> +    CmaFree:               0 kB
> +    HugePages_Total:       0
> +    HugePages_Free:        0
> +    HugePages_Rsvd:        0
> +    HugePages_Surp:        0
> +    Hugepagesize:       2048 kB
> +    Hugetlb:               0 kB
> +    DirectMap4k:      401152 kB
> +    DirectMap2M:    10008576 kB
> +    DirectMap1G:    24117248 kB
>  
>  MemTotal
>                Total usable RAM (i.e. physical RAM minus a few reserved
>                bits and the kernel binary code)
>  MemFree
> -              The sum of LowFree+HighFree
> +              Total free RAM. On highmem systems, the sum of LowFree+HighFree
>  MemAvailable
>                An estimate of how much memory is available for starting new
>                applications, without swapping. Calculated from MemFree,
> @@ -1005,8 +1020,9 @@ Buffers
>                Relatively temporary storage for raw disk blocks
>                shouldn't get tremendously large (20MB or so)
>  Cached
> -              in-memory cache for files read from the disk (the
> -              pagecache).  Doesn't include SwapCached
> +              In-memory cache for files read from the disk (the
> +              pagecache) as well as tmpfs & shmem.
> +              Doesn't include SwapCached.
>  SwapCached
>                Memory that once was swapped out, is swapped back in but
>                still also is in the swapfile (if memory is needed it
> @@ -1018,6 +1034,11 @@ Active
>  Inactive
>                Memory which has been less recently used.  It is more
>                eligible to be reclaimed for other purposes
> +Unevictable
> +              Memory that cannot be reclaimed, such as mlocked pages,
> +              ramfs backing pages, secret memfd pages etc.


A little imprecise, because this only includes memory to be mapped into
user space. For example, all kernel allocations are unevictable but not
accounted here.

Apart from that

Acked-by: David Hildenbrand <david@redhat.com>


-- 
Thanks,

David / dhildenb