On Sun, Feb 11, 2018 at 6:47 PM, Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > 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 >> <kirill@xxxxxxxxxxxxx> 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. OK, I'll review this yet again and resend tomorrow. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
