• Nick Piggin's avatar
    mm: purge fragmented percpu vmap blocks · 02b709df
    Nick Piggin authored
    Improve handling of fragmented per-CPU vmaps.  We previously don't free
    up per-CPU maps until all its addresses have been used and freed.  So
    fragmented blocks could fill up vmalloc space even if they actually had
    no active vmap regions within them.
    Add some logic to allow all CPUs to have these blocks purged in the case
    of failure to allocate a new vm area, and also put some logic to trim
    such blocks of a current CPU if we hit them in the allocation path (so
    as to avoid a large build up of them).
    Christoph reported some vmap allocation failures when using the per CPU
    vmap APIs in XFS, which cannot be reproduced after this patch and the
    previous bug fix.
    Cc: linux-mm@kvack.org
    Cc: stable@kernel.org
    Tested-by: default avatarChristoph Hellwig <hch@infradead.org>
    Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
vmalloc.c 60.8 KB