Messages in this thread |  | | From | Konstantin Khlebnikov <> | Date | Sun, 11 Feb 2018 18:55:27 +0300 | Subject | Re: [PATCH v2] mm/huge_memory.c: reorder operations in __split_huge_page_tail() |
| |
On Sun, Feb 11, 2018 at 6:47 PM, Kirill A. Shutemov <kirill@shutemov.name> 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@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.
OK, I'll review this yet again and resend tomorrow.
|  |