• Chris Wilson's avatar
    mm/vmap: Add a notifier for when we run out of vmap address space · 4da56b99
    Chris Wilson authored
    vmaps are temporary kernel mappings that may be of long duration.
    Reusing a vmap on an object is preferrable for a driver as the cost of
    setting up the vmap can otherwise dominate the operation on the object.
    However, the vmap address space is rather limited on 32bit systems and
    so we add a notification for vmap pressure in order for the driver to
    release any cached vmappings.
    The interface is styled after the oom-notifier where the callees are
    passed a pointer to an unsigned long counter for them to indicate if they
    have freed any space.
    v2: Guard the blocking notifier call with gfpflags_allow_blocking()
    v3: Correct typo in forward declaration and move to head of file
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: David Rientjes <rientjes@google.com>
    Cc: Roman Peniaev <r.peniaev@gmail.com>
    Cc: Mel Gorman <mgorman@techsingularity.net>
    Cc: linux-mm@kvack.org
    Cc: linux-kernel@vger.kernel.org
    Acked-by: Andrew Morton <akpm@linux-foundation.org> # for inclusion via DRM
    Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
    Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/1459777603-23618-3-git-send-email-chris@chris-wilson.co.ukReviewed-by: default avatarJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
vmalloc.c 68.7 KB