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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 80E53C43458 for ; Mon, 13 Jul 2026 16:36:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 983666B0120; Mon, 13 Jul 2026 12:36:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E4A66B0141; Mon, 13 Jul 2026 12:36:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 823306B0142; Mon, 13 Jul 2026 12:36:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 4D5876B0120 for ; Mon, 13 Jul 2026 12:36:23 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 664EB8C420 for ; Mon, 13 Jul 2026 15:19:43 +0000 (UTC) X-FDA: 84984113046.27.326E8C9 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf09.hostedemail.com (Postfix) with ESMTP id 84D73140008 for ; Mon, 13 Jul 2026 15:19:41 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=eNOeX5wB; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf09.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1783955981; b=VQgKbFoRxLEkrD3hMeefSPpWQ0xmvxBN7QUnYSqPhc7VLNTZsgBG5IB3H1enQwg5Iqf1hA cPA+OrOsB/S2BdhaZlWgauarF1xrwENewKSpHCEU9c/xYinVigYtUgkhEXoSYAPP+hT3vA vls7iEqRmmKRxuZhZrkxFIh5lOCa8dk= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=arm.com header.s=foss header.b=eNOeX5wB; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf09.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1783955981; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NaaRVxnBFj+SQ9aWp6Se6zorBMY3aLkJmBwF4iBsWUQ=; b=Bxu45saRyMxkzywUsY64+nRL5U3qu/vtPa7+saX0d6qHr+6DXfodqJ6TygAb2KLufa01E1 9BfHh0834/S4KZF0TPl3Ftakj8UB9GfOIE6B2LsUfP39n5y6thvEsD5d61IhKZbJLlc3sY kY9bF1xWPZ8zqS5m5stSUpBWZX/PWio= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2E8461576; Mon, 13 Jul 2026 08:19:36 -0700 (PDT) Received: from [10.164.19.52] (unknown [10.164.19.52]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0F5B23F93E; Mon, 13 Jul 2026 08:19:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1783955980; bh=6itNocGqdstfsGVwFY8Fldnsbq94BxJ1jweYynvGIyM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=eNOeX5wBC+l/3/3tHLXTnRTariYyyEtBlRXR+rHI/BOZuLuOp6vUDOhXvIHFDkrhg 4mvmbYS8yYUrx8p84rbdDf/KcvkLxe5gops5cM9kGRNw7IWd8jHuVrQslZk+3VOU0D tTRvCWvoP3paIHCoH71B9srt9i0aGKkHhZKhaS5E= Message-ID: Date: Mon, 13 Jul 2026 20:49:33 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 5/6] mm/vmalloc: map contiguous pages in batches for vmap() if possible To: Wen Jiang , akpm@linux-foundation.org, catalin.marinas@arm.com, linux-mm@kvack.org, urezki@gmail.com, will@kernel.org Cc: Xueyuan.chen21@gmail.com, ajd@linux.ibm.com, anshuman.khandual@arm.com, david@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, rppt@kernel.org, ryan.roberts@arm.com, "Barry Song (Xiaomi)" , Wen Jiang , Leo Yan References: <20260709073823.6643-1-jiangwen6@xiaomi.com> <20260709073823.6643-6-jiangwen6@xiaomi.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260709073823.6643-6-jiangwen6@xiaomi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 84D73140008 X-Rspam-User: X-Stat-Signature: px51w1d3dw6iwsijj7ucipmkgiy9gymp X-Rspamd-Server: rspam03 X-HE-Tag: 1783955981-389966 X-HE-Meta: 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 Dtglm3EJ 5xd6u3jBI8y0uQFPMO+JOmd3d2X3O2OYbyYWLji5wM31txEJo3jUcBx9uRkheTcx20/HzYjMrLHEE8iZGwRfAC4C0RY9aAa6gDB/wTXfMg5GbKiL2G1FwD3YEaNXN69EsD8ZGAgpkWxdvQwzAk+eQIOR8BjI4HplhF3vHrTtE4m6CfOXC52FCjEzwMEt13RgBlnGJByUUyiOBEYAIiaG2gPDHR+ygwsZlRraiv0aGJXEm9mqYJ3mWo0avPpifR3xXV2P5n9A70i1oE2JOotu9bh/k27VLAEU9IMww7otzun2eW8o75wG69vaTapTNQinrXp79oMWF/BdhVjs7f8brWNfh1qYoiyTTjDJvzTbhok6+jizp+rmkvfIqO3eHGoMG1Ojj3w2n5RsAH4xxE9h/SbmcCIe6Ze1eE49fwZIxg+6v6zcyTK8T/a2XbGdUJUX//QlAjj5SU/FlOn4tepttT5yTtA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 09/07/26 1:08 pm, Wen Jiang wrote: > From: "Barry Song (Xiaomi)" > > In many cases, the pages passed to vmap() may include high-order > pages. For example, the systemheap often allocates pages in descending > order: order 8, then 4, then 0. Currently, vmap() iterates over every > page individually—even pages inside a high-order block are handled > one by one. > > This patch detects physically contiguous pages (regardless of whether > they are compound or non-compound) by scanning with > num_pages_contiguous(), and maps them as a single contiguous block > whenever possible. The mapping order is determined by taking the > minimum of the contiguous page count and the pfn alignment, allowing > graceful degradation when pfn alignment is less than the contiguous > range. > > Pages with the same page_shift are coalesced and mapped via > vmap_pages_range_noflush_walk() to avoid page table rewalk. > > As users typically allocate memory in descending orders (e.g. > 8 → 4 → 0), once an order-0 page is encountered, we stop scanning > for contiguous pages since subsequent pages are likely order-0 as well. > > Signed-off-by: Barry Song (Xiaomi) > Co-developed-by: Dev Jain > Signed-off-by: Dev Jain > Signed-off-by: Wen Jiang > Tested-by: Xueyuan Chen > Tested-by: Leo Yan > --- > mm/vmalloc.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 85 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index d2a4d649af549..db0492151ad08 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3543,6 +3543,89 @@ void vunmap(const void *addr) > } > EXPORT_SYMBOL(vunmap); > > +static inline unsigned int vm_shift(pgprot_t prot, unsigned long size) > +{ > + if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) > + return PMD_SHIFT; > + > + return arch_vmap_pte_supported_shift(size); > +} Need to throw in a preparatory patch for this, which will (in addition to introduction of the vm_shift() function) do: diff --git a/mm/vmalloc.c b/mm/vmalloc.c index afaa14ebf17bb..dac87e1cd484b 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -4175,10 +4175,7 @@ void *__vmalloc_node_range_noprof(unsigned long size, unsigned long align, * supporting them. */ - if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) - shift = PMD_SHIFT; - else - shift = arch_vmap_pte_supported_shift(size); + shift = vm_shift(prot, size); align = max(original_align, 1UL << shift); } > + > +static inline int get_vmap_batch_order(struct page **pages, > + pgprot_t prot, unsigned int max_steps, unsigned int idx) > +{ > + unsigned int nr_contig; > + int order; > + > + if (!IS_ENABLED(CONFIG_HAVE_ARCH_HUGE_VMAP)) > + return 0; > + > + nr_contig = num_pages_contiguous(&pages[idx], max_steps); > + if (nr_contig < 2) > + return 0; > + > + order = ilog2(nr_contig); > + > + /* Limit order by pfn alignment */ > + order = min_t(int, order, __ffs(page_to_pfn(pages[idx]))); You missed Sashiko's point here :) the pfn may be zero and this will blow up. You can just first derive the pfn and do the clamping only when pfn > 0. > + > + if (vm_shift(prot, PAGE_SIZE << order) == PAGE_SHIFT) > + return 0; > + > + return order; > +} > +