From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 89E413DA7E3 for ; Wed, 25 Feb 2026 16:34:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772037300; cv=none; b=nvm06JzL9ZQ3UPYbLeUjuxfUJ7kQHYog4alnwN//kmByy6cWDOllpNrnUP5r3XGNOa/6n07I9vKGPkiqLDhsvDyRmPSHSG+NxZumefyz4BL7ewAlfsoqov19GTvTueYXZac/VVOWeCF4aS2YpQO/LoPLbYo0ZZ495fgeWzktzCA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772037300; c=relaxed/simple; bh=ebS9I8aai7kV4sU2PAFUm9jjqS6JNJmM9daxxIuyudA=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=sUwdfqLN/RdFPRLss6wO55pSNQVxvgYlD8GEKeJPltOF9EBdo9QWD3/jHPGquknuSNjnTs4Fedgueoiv2qWG/aK/fWKwvQwPTtZ1k2TDhSYH+PpBjVHwW6cSnH6klqHeYYAGpT4KVQyLc1p2nqDyzEE23cGwb3sk0jVMTxxWFZQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=Bv18Nsad; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Bv18Nsad" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4832c4621c2so67396655e9.3 for ; Wed, 25 Feb 2026 08:34:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772037297; x=1772642097; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=G/9fFi5oF0vRGQJfwEM4ETi3Y5U6mRHQzuEt7SowwhY=; b=Bv18NsadpvO4eYOM9CRb/cxuoqfyFYfgYVl1D5y5kBMoymEZ/VnmXWlx6R9FQSpMDB wHLyL2hbjR6WrrCjlwb97WOHgfCJkcO3q+nIzvRd5KZr/5PD8Y8ohfjnsHaUlvPpiL7+ kJSDmQU42IMovB6/YkTWgYlJEKpm6vfpF2koEKgbi5MrqmSplmI0u/5vnzbxDO68YLQ4 pU4TE+jp7bIAfaJkAkP2rw5Zi8ZfTrptTIrH9wPZeBMAMDlEsHGmFmv3GPESniIY5Zk0 dpukdmQ5NViG4WWtwbYXkiVa6y63qmXFH+gdJeUpKf57ZJo93zByrjy82nJDeDmDbZX5 jEzw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772037297; x=1772642097; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=G/9fFi5oF0vRGQJfwEM4ETi3Y5U6mRHQzuEt7SowwhY=; b=oPQzEXOwOVLtWd1Dqebqa0pgzM3/H02aUvJjdzvEb4vxb/NpKbrl68dXH+JkbNHdz6 kT95r7VFp6sn7spJi/b8zF61uo4HqgX5sGo+6bmr3rK6cQODGYWDcqm5Bev8bewdo4Pf GZFRvYWkm3bt73vQuo0/WfLJHdXOtIq5FbdZnqyEj0pzaP6XANKV4rFQ/B7F+hix7PRa fBYyQx4vP3uBjINwTmIBtu//v9W8D4ytc22JvhYtMXFimDNO0MnNcr2ubyiz3U8BTLdn 5JJj0/7KI4vnv8Z5hQG/JdnaUvoZ8CU+hpeDrjRAUoUyuc2nsRQfyWJiJ398pT2rWYn/ ZaIA== X-Forwarded-Encrypted: i=1; AJvYcCUN2Fdn70tg3Zt+HUj9crU+ifsqFshd27EB4qJELIcbAx1MwduL3xctr1kG/TVj6m0D6VFRoYAUy7yEMCE=@vger.kernel.org X-Gm-Message-State: AOJu0Yyni6nAsoEE2TQ2Y4h2/VnSnljkMoE8kYMbCL0hl6kly6qOrjKG tJADn4/Po88bKJP/WJxOJs05zmGd/G8UYJ0zARc+dWauP5x0dAtDFI8qp0Ogidp83YA8v9w3/FL lV7C86YvrT82/dw== X-Received: from wmbjr3.prod.google.com ([2002:a05:600c:5603:b0:480:6c79:b533]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:674f:b0:483:6ff1:18b with SMTP id 5b1f17b1804b1-483a9555bafmr280867955e9.0.1772037296543; Wed, 25 Feb 2026 08:34:56 -0800 (PST) Date: Wed, 25 Feb 2026 16:34:40 +0000 In-Reply-To: <20260225-page_alloc-unmapped-v1-0-e8808a03cd66@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260225-page_alloc-unmapped-v1-0-e8808a03cd66@google.com> X-Mailer: b4 0.14.3 Message-ID: <20260225-page_alloc-unmapped-v1-15-e8808a03cd66@google.com> Subject: [PATCH RFC 15/19] mm/page_alloc: rename ALLOC_NON_BLOCK back to _HARDER From: Brendan Jackman To: Borislav Petkov , Dave Hansen , Peter Zijlstra , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Vlastimil Babka , Wei Xu , Johannes Weiner , Zi Yan Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, rppt@kernel.org, Sumit Garg , derkling@google.com, reijiw@google.com, Will Deacon , rientjes@google.com, "Kalyazin, Nikita" , patrick.roy@linux.dev, "Itazuri, Takahiro" , Andy Lutomirski , David Kaplan , Thomas Gleixner , Brendan Jackman , Yosry Ahmed Content-Type: text/plain; charset="utf-8" Commit 1ebbb21811b7 ("mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves") renamed ALLOC_HARDER to ALLOC_NON_BLOCK because the former is "a vague description". However, vagueness is accurate here, this is a vague flag. It is not set for __GFP_NOMEMALLOC. It doesn't really mean "allocate without blocking" but rather "allow dipping into atomic reserves, _because_ of the need not to block". A later commit will need an alloc flag that really means "don't block here", so go back to the flag's old name and update the commentary to try and give it a slightly clearer meaning. Signed-off-by: Brendan Jackman --- mm/internal.h | 9 +++++---- mm/page_alloc.c | 8 ++++---- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index cac292dcd394f..5be53d25c89b7 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1372,9 +1372,10 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, #define ALLOC_OOM ALLOC_NO_WATERMARKS #endif -#define ALLOC_NON_BLOCK 0x10 /* Caller cannot block. Allow access - * to 25% of the min watermark or - * 62.5% if __GFP_HIGH is set. +#define ALLOC_HARDER 0x10 /* Because the caller cannot block, + * allow access * to 25% of the min + * watermark or 62.5% if __GFP_HIGH is + * set. */ #define ALLOC_MIN_RESERVE 0x20 /* __GFP_HIGH set. Allow access to 50% * of the min watermark. @@ -1391,7 +1392,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, #define ALLOC_KSWAPD 0x800 /* allow waking of kswapd, __GFP_KSWAPD_RECLAIM set */ /* Flags that allow allocations below the min watermark. */ -#define ALLOC_RESERVES (ALLOC_NON_BLOCK|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) +#define ALLOC_RESERVES (ALLOC_HARDER|ALLOC_MIN_RESERVE|ALLOC_HIGHATOMIC|ALLOC_OOM) enum ttu_flags; struct tlbflush_unmap_batch; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 14098474afd07..42b807faca5fe 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3392,7 +3392,7 @@ struct page *rmqueue_buddy(struct zone *preferred_zone, struct zone *zone, * reserves as failing now is worse than failing a * high-order atomic allocation in the future. */ - if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_NON_BLOCK))) + if (!page && (alloc_flags & (ALLOC_OOM|ALLOC_HARDER))) page = __rmqueue_smallest(zone, order, ft_high); if (!page) { @@ -3755,7 +3755,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark, * or (GFP_KERNEL & ~__GFP_DIRECT_RECLAIM) do not get * access to the min reserve. */ - if (alloc_flags & ALLOC_NON_BLOCK) + if (alloc_flags & ALLOC_HARDER) min -= min / 4; } @@ -4640,7 +4640,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) * 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_NON_BLOCK and ALLOC_MIN_RESERVE(__GFP_HIGH). + * set both ALLOC_HARDER and ALLOC_MIN_RESERVE(__GFP_HIGH). */ alloc_flags |= (__force int) (gfp_mask & (__GFP_HIGH | __GFP_KSWAPD_RECLAIM)); @@ -4651,7 +4651,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask, unsigned int order) * if it can't schedule. */ if (!(gfp_mask & __GFP_NOMEMALLOC)) { - alloc_flags |= ALLOC_NON_BLOCK; + alloc_flags |= ALLOC_HARDER; if (order > 0 && (alloc_flags & ALLOC_MIN_RESERVE)) alloc_flags |= ALLOC_HIGHATOMIC; -- 2.51.2