On Sun, Feb 11, 2018 at 06:32:10PM +0300, Konstantin Khlebnikov wrote: > On Sun, Feb 11, 2018 at 6:14 PM, Kirill A. Shutemov > <kir...@shutemov.name> wrote: > > On Sun, Feb 11, 2018 at 05:29:37PM +0300, Konstantin Khlebnikov wrote: > >> And replace page_ref_inc()/page_ref_add() with page_ref_unfreeze() which > >> is made especially for that and has semantic of smp_store_release(). > > > > Nak on this part. > > > > page_ref_unfreeze() uses atomic_set() which neglects the situation in the > > comment you're removing. > > Why? look into x86 smp_store_release > for PPro it use same sequence smp_wb + WRITE_ONCE > As I see spin_unlock uses exactly this macro. > > Anyway if page_ref_unfreeze cannot handle races with > get_page_unless_zero() then it completely useless,
Okay, fair enough. But please call it out it the commit message. -- Kirill A. Shutemov
