From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C6BEC5479D for ; Wed, 11 Jan 2023 15:19:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236274AbjAKPTD (ORCPT ); Wed, 11 Jan 2023 10:19:03 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234134AbjAKPSz (ORCPT ); Wed, 11 Jan 2023 10:18:55 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1BB8167F1 for ; Wed, 11 Jan 2023 07:18:53 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id A127A17D5A; Wed, 11 Jan 2023 15:18:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1673450331; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=hwhw0xueoRQfeRsCWppft2gnEQP/FMWyCk6R1o8Asho=; b=KmKPjMNWZsCwVeaDFB+fRZ5uBcKXjpMBjGXWHFq0tWO9XCW+39p8TZVLv5WdxlhMe8KXFz x/LWWti9rB+G7qdqWy9bSiET+4PwJ/r5dmYLAT6eqINOZn8wpfzcFOfJ9SqA63+fLD/VX4 JEzqyib8FTGmYuagESKEYJp2hvN2Mb0= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7FE3C13591; Wed, 11 Jan 2023 15:18:51 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id 8Y5eHFvTvmMSLgAAMHmgww (envelope-from ); Wed, 11 Jan 2023 15:18:51 +0000 Date: Wed, 11 Jan 2023 16:18:50 +0100 From: Michal Hocko To: Mel Gorman Cc: Linux-MM , Andrew Morton , NeilBrown , Thierry Reding , Matthew Wilcox , Vlastimil Babka , LKML Subject: Re: [PATCH 1/7] mm/page_alloc: Rename ALLOC_HIGH to ALLOC_MIN_RESERVE Message-ID: References: <20230109151631.24923-1-mgorman@techsingularity.net> <20230109151631.24923-2-mgorman@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230109151631.24923-2-mgorman@techsingularity.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 09-01-23 15:16:25, Mel Gorman wrote: > __GFP_HIGH aliases to ALLOC_HIGH but the name does not really hint > what it means. As ALLOC_HIGH is internal to the allocator, rename > it to ALLOC_MIN_RESERVE to document that the min reserves can > be depleted. > > Signed-off-by: Mel Gorman > Acked-by: Vlastimil Babka Naming is hard but ALLOC_HIGH is definitely much more confusing as it can collide with high watermark. ALLOC_MIN_RESERVE says that some reserves are involved. ALl the reserves are below min watermark by defition but I cannot really come up with a better name. I do not think we want to encode the amount of reserves into the name. Acked-by: Michal Hocko Thanks! > --- > mm/internal.h | 4 +++- > mm/page_alloc.c | 8 ++++---- > 2 files changed, 7 insertions(+), 5 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index bcf75a8b032d..403e4386626d 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -736,7 +736,9 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, > #endif > > #define ALLOC_HARDER 0x10 /* try to alloc harder */ > -#define ALLOC_HIGH 0x20 /* __GFP_HIGH set */ > +#define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50% > + * of the min watermark. > + */ > #define ALLOC_CPUSET 0x40 /* check for correct cpuset */ > #define ALLOC_CMA 0x80 /* allow allocations from CMA areas */ > #ifdef CONFIG_ZONE_DMA32 > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 0745aedebb37..244c1e675dc8 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -3976,7 +3976,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, > /* free_pages may go negative - that's OK */ > free_pages -= __zone_watermark_unusable_free(z, order, alloc_flags); > > - if (alloc_flags & ALLOC_HIGH) > + if (alloc_flags & ALLOC_MIN_RESERVE) > min -= min / 2; > > if (unlikely(alloc_harder)) { > @@ -4818,18 +4818,18 @@ gfp_to_alloc_flags(gfp_t gfp_mask) > unsigned int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET; > > /* > - * __GFP_HIGH is assumed to be the same as ALLOC_HIGH > + * __GFP_HIGH is assumed to be the same as ALLOC_MIN_RESERVE > * and __GFP_KSWAPD_RECLAIM is assumed to be the same as ALLOC_KSWAPD > * to save two branches. > */ > - BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH); > + BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_MIN_RESERVE); > BUILD_BUG_ON(__GFP_KSWAPD_RECLAIM != (__force gfp_t) ALLOC_KSWAPD); > > /* > * The caller may dip into page reserves a bit more if the caller > * cannot run direct reclaim, or if the caller has realtime scheduling > * policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will > - * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH). > + * set both ALLOC_HARDER (__GFP_ATOMIC) and ALLOC_MIN_RESERVE(__GFP_HIGH). > */ > alloc_flags |= (__force int) > (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); > -- > 2.35.3 -- Michal Hocko SUSE Labs