• Manfred Spraul's avatar
    ipc/msg: increase MSGMNI, remove scaling · 0050ee05
    Manfred Spraul authored
    SysV can be abused to allocate locked kernel memory.  For most systems, a
    small limit doesn't make sense, see the discussion with regards to SHMMAX.
    
    Therefore: increase MSGMNI to the maximum supported.
    
    And: If we ignore the risk of locking too much memory, then an automatic
    scaling of MSGMNI doesn't make sense.  Therefore the logic can be removed.
    
    The code preserves auto_msgmni to avoid breaking any user space applications
    that expect that the value exists.
    
    Notes:
    1) If an administrator must limit the memory allocations, then he can set
    MSGMNI as necessary.
    
    Or he can disable sysv entirely (as e.g. done by Android).
    
    2) MSGMAX and MSGMNB are intentionally not increased, as these values are used
    to control latency vs. throughput:
    If MSGMNB is large, then msgsnd() just returns and more messages can be queued
    before a task switch to a task that calls msgrcv() is forced.
    
    [akpm@linux-foundation.org: coding-style fixes]
    Signed-off-by: default avatarManfred Spraul <manfred@colorfullife.com>
    Cc: Davidlohr Bueso <dave@stgolabs.net>
    Cc: Rafael Aquini <aquini@redhat.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    0050ee05
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