• M
    [S390] Optimize storage key operations for anon pages · a4b526b3
    Martin Schwidefsky 提交于
    For anonymous pages without a swap cache backing the check in
    page_remove_rmap for the physical dirty bit in page_remove_rmap is
    unnecessary. The instructions that are used to check and reset the dirty
    bit are expensive. Removing the check noticably speeds up process exit.
    In addition the clearing of the dirty bit in __SetPageUptodate is
    pointless as well. With these two changes there is no storage key
    operation for an anonymous page anymore if it does not hit the swap
    space.
    
    The micro benchmark which repeatedly executes an empty shell script
    gets about 5% faster.
    Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
    a4b526b3
page-flags.h 10.6 KB