From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id BF55B440615 for ; Fri, 17 Feb 2017 11:22:07 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id h7so9088842wjy.6 for ; Fri, 17 Feb 2017 08:22:07 -0800 (PST) Received: from gum.cmpxchg.org (gum.cmpxchg.org. [85.214.110.215]) by mx.google.com with ESMTPS id o39si13863558wrc.14.2017.02.17.08.22.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 17 Feb 2017 08:22:06 -0800 (PST) Date: Fri, 17 Feb 2017 11:22:02 -0500 From: Johannes Weiner Subject: Re: [PATCH V3 2/7] mm: move MADV_FREE pages into LRU_INACTIVE_FILE list Message-ID: <20170217162202.GE23735@cmpxchg.org> References: <5c38c5f4d91e92ce86ee4f253e49c78708094632.1487100204.git.shli@fb.com> <20170216175253.GB20791@cmpxchg.org> <20170217003524.GA95440@shli-mbp.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170217003524.GA95440@shli-mbp.local> Sender: owner-linux-mm@kvack.org List-ID: To: Shaohua Li Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Kernel-team@fb.com, mhocko@suse.com, minchan@kernel.org, hughd@google.com, riel@redhat.com, mgorman@techsingularity.net, akpm@linux-foundation.org On Thu, Feb 16, 2017 at 04:35:25PM -0800, Shaohua Li wrote: > On Thu, Feb 16, 2017 at 12:52:53PM -0500, Johannes Weiner wrote: > > On Tue, Feb 14, 2017 at 11:36:08AM -0800, Shaohua Li wrote: > > > @@ -126,4 +126,24 @@ static __always_inline enum lru_list page_lru(struct page *page) > > > > > > #define lru_to_page(head) (list_entry((head)->prev, struct page, lru)) > > > > > > +/* > > > + * lazyfree pages are clean anonymous pages. They have SwapBacked flag cleared > > > + * to destinguish normal anonymous pages. > > > + */ > > > +static inline void set_page_lazyfree(struct page *page) > > > +{ > > > + VM_BUG_ON_PAGE(!PageAnon(page) || !PageSwapBacked(page), page); > > > + ClearPageSwapBacked(page); > > > +} > > > + > > > +static inline void clear_page_lazyfree(struct page *page) > > > +{ > > > + VM_BUG_ON_PAGE(!PageAnon(page) || PageSwapBacked(page), page); > > > + SetPageSwapBacked(page); > > > +} > > > + > > > +static inline bool page_is_lazyfree(struct page *page) > > > +{ > > > + return PageAnon(page) && !PageSwapBacked(page); > > > +} > > > > Sorry for not getting to v2 in time, but I have to say I strongly > > agree with your first iterations and would much prefer this to be > > open-coded. > > > > IMO this needlessly introduces a new state opaquely called "lazyfree", > > when really that's just anonymous pages that don't need to be swapped > > before reclaim - PageAnon && !PageSwapBacked. Very simple MM concept. > > > > That especially shows when we later combine it with page_is_file_cache > > checks like the next patch does. > > > > The rest of the patch looks good to me. > > Thanks! I do agree checking PageSwapBacked is clearer, but Minchan convinced me > because of the accounting issue. Where do you suggest we should put the > accounting to? I now proposed quite a few changes to the setting and clearing sites, so it's harder to judge, but AFAICT once those sites are consolidated, open-coding the stat updates as well shouldn't be too bad, right? One site to clear during MADV_FREE, one site to set during reclaim. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org