• Christoph Lameter's avatar
    vmalloc: show vmalloced areas via /proc/vmallocinfo · a10aa579
    Christoph Lameter authored
    Implement a new proc file that allows the display of the currently allocated
    vmalloc memory.
    It allows to see the users of vmalloc.  That is important if vmalloc space is
    scarce (i386 for example).
    And it's going to be important for the compound page fallback to vmalloc.
    Many of the current users can be switched to use compound pages with fallback.
     This means that the number of users of vmalloc is reduced and page tables no
    longer necessary to access the memory.  /proc/vmallocinfo allows to review how
    that reduction occurs.
    If memory becomes fragmented and larger order allocations are no longer
    possible then /proc/vmallocinfo allows to see which compound page allocations
    fell back to virtual compound pages.  That is important for new users of
    virtual compound pages.  Such as order 1 stack allocation etc that may
    fallback to virtual compound pages in the future.
    /proc/vmallocinfo permissions are made readable-only-by-root to avoid possible
    information leakage.
    [akpm@linux-foundation.org: coding-style fixes]
    [akpm@linux-foundation.org: CONFIG_MMU=n build fix]
    Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
    Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Cc: Hugh Dickins <hugh@veritas.com>
    Cc: Nick Piggin <nickpiggin@yahoo.com.au>
    Cc: Arjan van de Ven <arjan@infradead.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
vmalloc.c 21.2 KB