lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Fri, 17 Feb 2017 11:11:05 -0500 From: Johannes Weiner <hannes@...xchg.org> To: Minchan Kim <minchan@...nel.org> Cc: Shaohua Li <shli@...com>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Kernel-team@...com, mhocko@...e.com, hughd@...gle.com, riel@...hat.com, mgorman@...hsingularity.net, akpm@...ux-foundation.org Subject: Re: [PATCH V3 3/7] mm: reclaim MADV_FREE pages Hi Minchan, On Fri, Feb 17, 2017 at 02:45:55PM +0900, Minchan Kim wrote: > On Thu, Feb 16, 2017 at 04:27:18PM -0800, Shaohua Li wrote: > > On Thu, Feb 16, 2017 at 01:40:18PM -0500, Johannes Weiner wrote: > > > On Tue, Feb 14, 2017 at 11:36:09AM -0800, Shaohua Li wrote: > > > > @@ -1419,11 +1419,18 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma, > > > > VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page), > > > > page); > > > > > > > > - if (!PageDirty(page) && (flags & TTU_LZFREE)) { > > > > - /* It's a freeable page by MADV_FREE */ > > > > - dec_mm_counter(mm, MM_ANONPAGES); > > > > - rp->lazyfreed++; > > > > - goto discard; > > > > + if (flags & TTU_LZFREE) { > > > > + if (!PageDirty(page)) { > > > > + /* It's a freeable page by MADV_FREE */ > > > > + dec_mm_counter(mm, MM_ANONPAGES); > > > > + rp->lazyfreed++; > > > > + goto discard; > > > > + } else { > > > > + set_pte_at(mm, address, pvmw.pte, pteval); > > > > + ret = SWAP_FAIL; > > > > + page_vma_mapped_walk_done(&pvmw); > > > > + break; > > > > + } > > > > > > I don't understand why we need the TTU_LZFREE bit in general. More on > > > that below at the callsite. > > > > Sounds useless flag, don't see any reason we shouldn't free the MADV_FREE page > > in places other than reclaim. Looks TTU_UNMAP is useless too.. > > Agree on TTU_UNMAP but for example, THP split doesn't mean free lazyfree pages, > I think. Anon THP splitting uses the migration branch, so we should be fine.
Powered by blists - more mailing lists