From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f73.google.com (mail-ed1-f73.google.com [209.85.208.73]) (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 005453E9F9C for ; Wed, 25 Feb 2026 16:34:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772037298; cv=none; b=mRwj44X8Rolamqp3QvpeF3PYrlhu3ND9XgOdZKwMh47ozEZyR/nJ7rtM1+fl4b8Vnzg1e3SLCxZrAo3u77qsipcc1wLFf3QWFk93veGS0K8oBgBH0Cjj677mtPoluJCNNoCE/AfDNYWv5TkIC6zkvfjQU5VA1GALo/YYQe5j22k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772037298; c=relaxed/simple; bh=75hKgIS9RzMMp4owYlRuElrSxMDZa6gGyt78/Cpptfw=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=WTFGCKdpfo7bvTri/HaB9DR8T+76O5l6sPNRyFTD1gQQyOQzVztNkzf17soLOZ+ENaQbfRoMOBa8olE01sZ3yP5h7SkDlRlAjyW1wqwJb2DZrtVlZJ/KhKTixbUM/Uh4pRTTLCsSpiHu6PnscfkEtGrT36XU1pY4cL4MUgSwzqE= 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=uEQbhqLF; arc=none smtp.client-ip=209.85.208.73 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="uEQbhqLF" Received: by mail-ed1-f73.google.com with SMTP id 4fb4d7f45d1cf-65fa4713bc6so626965a12.1 for ; Wed, 25 Feb 2026 08:34:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772037295; x=1772642095; 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=q51ijtBTrIsvjhX+iA1BrCEddMf5G3kZ1UUUAgabwFs=; b=uEQbhqLFMwTn64Ph8OLzH64BwE2gtgPLKG80QwZm1/yQUOCF6pgQa6NwGYAzIuHx5R M2B4U1hbRpOKkyoAizk1F+eUkEM6sXFLYMvKkwcOaZrM4GNW/Pg3k5lemFbZgw/t8mUw /PaVljvN/bgaYZkXktBsvULS18GGxif+XYfQvo+jAV30ZWcggubBOQWoDPm/9WekzC6G ECztXvN7eHPN7yVUyQfW4mGpJ/+Ky0qHIWNEiiGyyMAHpfNnaOFJgQnAtmQugFuxC1Ei 8Oo4MTVwEbVkLAJnHx3HfC/5nkVszGmOAbWIo6RaOKfRqh/SwtCYrMjRurpTpoi5xGzg 0ZmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772037295; x=1772642095; 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=q51ijtBTrIsvjhX+iA1BrCEddMf5G3kZ1UUUAgabwFs=; b=ezSvtL554Y0fbi86GdZUqo1JPBh1ui6f5MSvbGm6pJTZV1Gs9AYwtJ3u41uQxnnVlL z29uXp+meJ28XgcJiyrGDZSev+cBFZp/9o/Ni4M2fQiqtofJGV5tg3LYclVdFAr4K/sU 1MaEma+7ikhxru1gCUNdi1eaZWYh1WtPyIR4trwYxtuPgYVnZqmAyiHFM9awCy5fqITl 990244biN+HxOW/lQ2Wrvb6bP/oyhMSE1xqXpmTyZR29HkirhgN/8Qr2V21iwQUKGIQp uDdhd/lDYbzdv4Q3iusKT+Dt0ERSdgVn50Gd1dxC+wsgD3oxBwzi6LY33X5Hr43RIYGt iZQg== X-Forwarded-Encrypted: i=1; AJvYcCXItsZJTLHaYjO6p2xkpPzYn65y+FyuSc1PD32MKzcfCVHuu7wRuCTLopyHQqkLcgJ12Aj73gLKWHdv1XI=@vger.kernel.org X-Gm-Message-State: AOJu0YzhMA1x87zLWXlXHIaL1/Hal1/Jqt1lccFrbyNi2vMR5ce4qAmK LYXgXTd119onsRy6cMcl7k7xIeK32lenMIqxdnYF09AQQPpnw3aq5M4isiDPX3X91nUiYML2Dhd 4sRCmWE0G8PPwWw== X-Received: from edsj15.prod.google.com ([2002:a50:ed0f:0:b0:64b:8031:e69a]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6402:848:b0:658:bf9f:75be with SMTP id 4fb4d7f45d1cf-65f7bb13cd0mr2490510a12.16.1772037295237; Wed, 25 Feb 2026 08:34:55 -0800 (PST) Date: Wed, 25 Feb 2026 16:34:39 +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-v1-14-e8808a03cd66@google.com> Subject: [PATCH RFC 14/19] mm/page_alloc: separate pcplists by freetype flags 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" The normal freelists are already separated by this flag, so now update the pcplists accordingly. This follows the most "obvious" design where __GFP_UNMAPPED is supported at arbitrary orders. If necessary, it would be possible to avoid the proliferation of pcplists by restricting orders that can be allocated from them with this FREETYPE_UNMAPPED. On the other hand, there's currently no usecase for movable/reclaimable unmapped memory, and constraining the migratetype doesn't have any tricky plumbing implications. So, take advantage of that and assume that FREETYPE_UNMAPPED implies MIGRATE_UNMOVABLE. Overall, this just takes the existing space of pindices and tacks another bank on the end. For !THP this is just 4 more lists, with THP there is a single additional list for hugepages. Signed-off-by: Brendan Jackman --- include/linux/mmzone.h | 11 ++++++++++- mm/page_alloc.c | 44 +++++++++++++++++++++++++++++++++----------- 2 files changed, 43 insertions(+), 12 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 301328cbb8449..fc242b4090441 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -692,8 +692,17 @@ enum zone_watermarks { #else #define NR_PCP_THP 0 #endif +/* + * FREETYPE_UNMAPPED can currently only be used with MIGRATE_UNMOVABLE, no for + * those there's no need to encode the migratetype in the pindex. + */ +#ifdef CONFIG_PAGE_ALLOC_UNMAPPED +#define NR_UNMAPPED_PCP_LISTS (PAGE_ALLOC_COSTLY_ORDER + 1 + !!NR_PCP_THP) +#else +#define NR_UNMAPPED_PCP_LISTS 0 +#endif #define NR_LOWORDER_PCP_LISTS (MIGRATE_PCPTYPES * (PAGE_ALLOC_COSTLY_ORDER + 1)) -#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP) +#define NR_PCP_LISTS (NR_LOWORDER_PCP_LISTS + NR_PCP_THP + NR_UNMAPPED_PCP_LISTS) /* * Flags used in pcp->flags field. diff --git a/mm/page_alloc.c b/mm/page_alloc.c index fa12fff2182c7..14098474afd07 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -729,18 +729,30 @@ static void bad_page(struct page *page, const char *reason) add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); } -static inline unsigned int order_to_pindex(int migratetype, int order) +static inline unsigned int order_to_pindex(freetype_t freetype, int order) { + int migratetype = free_to_migratetype(freetype); + + VM_BUG_ON(migratetype >= MIGRATE_PCPTYPES); + VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER && + (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) || order != HPAGE_PMD_ORDER)); + + /* FREETYPE_UNMAPPED currently always means MIGRATE_UNMOVABLE. */ + if (freetype_flags(freetype) & FREETYPE_UNMAPPED) { + int order_offset = order; + + VM_BUG_ON(migratetype != MIGRATE_UNMOVABLE); + if (order > PAGE_ALLOC_COSTLY_ORDER) + order_offset = PAGE_ALLOC_COSTLY_ORDER + 1; + + return NR_LOWORDER_PCP_LISTS + NR_PCP_THP + order_offset; + } + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { bool movable = migratetype == MIGRATE_MOVABLE; - if (order > PAGE_ALLOC_COSTLY_ORDER) { - VM_BUG_ON(order != HPAGE_PMD_ORDER); - + if (order > PAGE_ALLOC_COSTLY_ORDER) return NR_LOWORDER_PCP_LISTS + movable; - } - } else { - VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); } return (MIGRATE_PCPTYPES * order) + migratetype; @@ -748,8 +760,18 @@ static inline unsigned int order_to_pindex(int migratetype, int order) static inline int pindex_to_order(unsigned int pindex) { - int order = pindex / MIGRATE_PCPTYPES; + unsigned int unmapped_base = NR_LOWORDER_PCP_LISTS + NR_PCP_THP; + int order; + if (pindex >= unmapped_base) { + order = pindex - unmapped_base; + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && + order > PAGE_ALLOC_COSTLY_ORDER) + return HPAGE_PMD_ORDER; + return order; + } + + order = pindex / MIGRATE_PCPTYPES; if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { if (pindex >= NR_LOWORDER_PCP_LISTS) order = HPAGE_PMD_ORDER; @@ -2970,7 +2992,7 @@ static bool free_frozen_page_commit(struct zone *zone, */ pcp->alloc_factor >>= 1; __count_vm_events(PGFREE, 1 << order); - pindex = order_to_pindex(free_to_migratetype(freetype), order); + pindex = order_to_pindex(freetype, order); list_add(&page->pcp_list, &pcp->lists[pindex]); pcp->count += 1 << order; @@ -3490,7 +3512,7 @@ static struct page *rmqueue_pcplist(struct zone *preferred_zone, * frees. */ pcp->free_count >>= 1; - list = &pcp->lists[order_to_pindex(free_to_migratetype(freetype), order)]; + list = &pcp->lists[order_to_pindex(freetype, order)]; page = __rmqueue_pcplist(zone, order, freetype, alloc_flags, pcp, list); pcp_spin_unlock(pcp, UP_flags); if (page) { @@ -5275,7 +5297,7 @@ unsigned long alloc_pages_bulk_noprof(gfp_t gfp, int preferred_nid, goto failed; /* Attempt the batch allocation */ - pcp_list = &pcp->lists[order_to_pindex(free_to_migratetype(ac.freetype), 0)]; + pcp_list = &pcp->lists[order_to_pindex(ac.freetype, 0)]; while (nr_populated < nr_pages) { /* Skip existing pages */ -- 2.51.2