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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> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: DEA0B20006 X-Stat-Signature: iwqm3ogp5wcenr8uuai6bqcifj4myib9 X-HE-Tag: 1673450333-70559 X-HE-Meta: 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 x4dX+YpT G+qeWtvu3lLKH1Z0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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