• Bron Gondwana's avatar
    mm/page-writeback: highmem_is_dirtyable option · 195cf453
    Bron Gondwana authored
    Add vm.highmem_is_dirtyable toggle
    
    A 32 bit machine with HIGHMEM64 enabled running DCC has an MMAPed file of
    approximately 2Gb size which contains a hash format that is written
    randomly by the dbclean process.  On 2.6.16 this process took a few
    minutes.  With lowmem only accounting of dirty ratios, this takes about 12
    hours of 100% disk IO, all random writes.
    
    Include a toggle in /proc/sys/vm/highmem_is_dirtyable which can be set to 1 to
    add the highmem back to the total available memory count.
    
    [akpm@linux-foundation.org: Fix the CONFIG_DETECT_SOFTLOCKUP=y build]
    Signed-off-by: default avatarBron Gondwana <brong@fastmail.fm>
    Cc: Ethan Solomita <solo@google.com>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: WU Fengguang <wfg@mail.ustc.edu.cn>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    195cf453
sysctl.c 68.2 KB