From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751848AbeBZFSz (ORCPT ); Mon, 26 Feb 2018 00:18:55 -0500 Received: from mga02.intel.com ([134.134.136.20]:63908 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750793AbeBZFSx (ORCPT ); Mon, 26 Feb 2018 00:18:53 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.47,396,1515484800"; d="scan'208";a="21050134" From: "Huang\, Ying" To: Minchan Kim Cc: Andrew Morton , lkml , linux-mm , Hugh Dickins , "Kirill A. Shutemov" Subject: Re: [PATCH RESEND 1/2] mm: swap: clean up swap readahead References: <20180220085249.151400-1-minchan@kernel.org> <20180220085249.151400-2-minchan@kernel.org> <874lm83zho.fsf@yhuang-dev.intel.com> <20180226045617.GA112402@rodete-desktop-imager.corp.google.com> Date: Mon, 26 Feb 2018 13:18:50 +0800 In-Reply-To: <20180226045617.GA112402@rodete-desktop-imager.corp.google.com> (Minchan Kim's message of "Mon, 26 Feb 2018 13:56:17 +0900") Message-ID: <87d10stjk5.fsf@yhuang-dev.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Minchan Kim writes: > On Fri, Feb 23, 2018 at 04:02:27PM +0800, Huang, Ying wrote: >> writes: >> [snip] >> >> > diff --git a/mm/swap_state.c b/mm/swap_state.c >> > index 39ae7cfad90f..c56cce64b2c3 100644 >> > --- a/mm/swap_state.c >> > +++ b/mm/swap_state.c >> > @@ -332,32 +332,38 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, >> > unsigned long addr) >> > { >> > struct page *page; >> > - unsigned long ra_info; >> > - int win, hits, readahead; >> > >> > page = find_get_page(swap_address_space(entry), swp_offset(entry)); >> > >> > INC_CACHE_INFO(find_total); >> > if (page) { >> > + bool vma_ra = swap_use_vma_readahead(); >> > + bool readahead = TestClearPageReadahead(page); >> > + >> >> TestClearPageReadahead() cannot be called for compound page. As in >> >> PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) >> TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) >> >> > INC_CACHE_INFO(find_success); >> > if (unlikely(PageTransCompound(page))) >> > return page; >> > - readahead = TestClearPageReadahead(page); >> >> So we can only call it here after checking whether page is compound. > > Hi Huang, > > Thanks for cathing this. > However, I don't see the reason we should rule out THP page for > readahead marker. Could't we relax the rule? > > I hope we can do so that we could remove PageTransCompound check > for readahead marker, which makes code ugly. > > From 748b084d5c3960ec2418d8c51a678aada30f1072 Mon Sep 17 00:00:00 2001 > From: Minchan Kim > Date: Mon, 26 Feb 2018 13:46:43 +0900 > Subject: [PATCH] mm: relax policy for PG_readahead > > This flag is in use for anon THP page so let's relax it. > > Cc: Kirill A. Shutemov > Signed-off-by: Minchan Kim > --- > include/linux/page-flags.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index e34a27727b9a..f12d4dfae580 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -318,8 +318,8 @@ PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) > /* PG_readahead is only used for reads; PG_reclaim is only for writes */ > PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) > TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) > -PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) > - TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) > +PAGEFLAG(Readahead, reclaim, PF_NO_TAIL) > + TESTCLEARFLAG(Readahead, reclaim, PF_NO_TAIL) > > #ifdef CONFIG_HIGHMEM > /* We never set Readahead bit for THP in reality. The original code acts as document for this. I don't think it is a good idea to change this without a good reason. Best Regards, Huang, Ying From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f72.google.com (mail-pl0-f72.google.com [209.85.160.72]) by kanga.kvack.org (Postfix) with ESMTP id BA1BA6B0005 for ; Mon, 26 Feb 2018 00:18:54 -0500 (EST) Received: by mail-pl0-f72.google.com with SMTP id b2so7073697plm.23 for ; Sun, 25 Feb 2018 21:18:54 -0800 (PST) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTPS id q25si5073645pge.457.2018.02.25.21.18.53 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 25 Feb 2018 21:18:53 -0800 (PST) From: "Huang\, Ying" Subject: Re: [PATCH RESEND 1/2] mm: swap: clean up swap readahead References: <20180220085249.151400-1-minchan@kernel.org> <20180220085249.151400-2-minchan@kernel.org> <874lm83zho.fsf@yhuang-dev.intel.com> <20180226045617.GA112402@rodete-desktop-imager.corp.google.com> Date: Mon, 26 Feb 2018 13:18:50 +0800 In-Reply-To: <20180226045617.GA112402@rodete-desktop-imager.corp.google.com> (Minchan Kim's message of "Mon, 26 Feb 2018 13:56:17 +0900") Message-ID: <87d10stjk5.fsf@yhuang-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , lkml , linux-mm , Hugh Dickins , "Kirill A. Shutemov" Minchan Kim writes: > On Fri, Feb 23, 2018 at 04:02:27PM +0800, Huang, Ying wrote: >> writes: >> [snip] >> >> > diff --git a/mm/swap_state.c b/mm/swap_state.c >> > index 39ae7cfad90f..c56cce64b2c3 100644 >> > --- a/mm/swap_state.c >> > +++ b/mm/swap_state.c >> > @@ -332,32 +332,38 @@ struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, >> > unsigned long addr) >> > { >> > struct page *page; >> > - unsigned long ra_info; >> > - int win, hits, readahead; >> > >> > page = find_get_page(swap_address_space(entry), swp_offset(entry)); >> > >> > INC_CACHE_INFO(find_total); >> > if (page) { >> > + bool vma_ra = swap_use_vma_readahead(); >> > + bool readahead = TestClearPageReadahead(page); >> > + >> >> TestClearPageReadahead() cannot be called for compound page. As in >> >> PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) >> TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) >> >> > INC_CACHE_INFO(find_success); >> > if (unlikely(PageTransCompound(page))) >> > return page; >> > - readahead = TestClearPageReadahead(page); >> >> So we can only call it here after checking whether page is compound. > > Hi Huang, > > Thanks for cathing this. > However, I don't see the reason we should rule out THP page for > readahead marker. Could't we relax the rule? > > I hope we can do so that we could remove PageTransCompound check > for readahead marker, which makes code ugly. > > From 748b084d5c3960ec2418d8c51a678aada30f1072 Mon Sep 17 00:00:00 2001 > From: Minchan Kim > Date: Mon, 26 Feb 2018 13:46:43 +0900 > Subject: [PATCH] mm: relax policy for PG_readahead > > This flag is in use for anon THP page so let's relax it. > > Cc: Kirill A. Shutemov > Signed-off-by: Minchan Kim > --- > include/linux/page-flags.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h > index e34a27727b9a..f12d4dfae580 100644 > --- a/include/linux/page-flags.h > +++ b/include/linux/page-flags.h > @@ -318,8 +318,8 @@ PAGEFLAG(MappedToDisk, mappedtodisk, PF_NO_TAIL) > /* PG_readahead is only used for reads; PG_reclaim is only for writes */ > PAGEFLAG(Reclaim, reclaim, PF_NO_TAIL) > TESTCLEARFLAG(Reclaim, reclaim, PF_NO_TAIL) > -PAGEFLAG(Readahead, reclaim, PF_NO_COMPOUND) > - TESTCLEARFLAG(Readahead, reclaim, PF_NO_COMPOUND) > +PAGEFLAG(Readahead, reclaim, PF_NO_TAIL) > + TESTCLEARFLAG(Readahead, reclaim, PF_NO_TAIL) > > #ifdef CONFIG_HIGHMEM > /* We never set Readahead bit for THP in reality. The original code acts as document for this. I don't think it is a good idea to change this without a good reason. Best Regards, Huang, Ying -- 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