• Paul Mackerras's avatar
    [PATCH] flush_icache_user_range (v2.5.4) · e97fde15
    Paul Mackerras authored
    The patch below changes access_process_vm to use a new architecture
    hook, flush_icache_user_range, instead of flush_icache_page, and adds
    a definition of flush_icache_user_range which does the same thing as
    flush_icache_page for all architectures except PPC.  (The PPC update
    that is in Linus' BK tree already includes a suitable definition of
    flush_icache_user_range.)
    
    The reason for doing this is that when flush_icache_page is called
    from do_no_page or do_swap_page, I want to be able to do the flush
    conditionally, based on the state of the page.  In contrast,
    access_process_vm needs to do the flush unconditionally since it has
    just modified the page.  In the access_process_vm case it is useful to
    have the information about the user address and length that have been
    modified since then we can just flush the affected cache lines rather
    than the whole page.
    
    This patch should make it easy to improve performance on alpha, since
    there (as I understand it) the icache flush is not needed at all in
    do_no_page or do_swap_page, but is needed in access_process_vm.  All
    that is needed is to make flush_icache_page a noop on alpha.  The
    patch below doesn't do this, I'll let the alpha maintainers push that
    change if they want.
    e97fde15
cachetlb.txt 15.1 KB