From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 77703D6; Mon, 27 Nov 2023 07:10:41 -0800 (PST) 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 CAC2F2F4; Mon, 27 Nov 2023 07:11:28 -0800 (PST) Received: from raptor (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EC8E23F6C4; Mon, 27 Nov 2023 07:10:35 -0800 (PST) Date: Mon, 27 Nov 2023 15:10:33 +0000 From: Alexandru Elisei To: David Hildenbrand Cc: catalin.marinas@arm.com, will@kernel.org, oliver.upton@linux.dev, maz@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, arnd@arndb.de, akpm@linux-foundation.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mhiramat@kernel.org, rppt@kernel.org, hughd@google.com, pcc@google.com, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, eugenis@google.com, kcc@google.com, hyesoo.yu@samsung.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH RFC v2 15/27] arm64: mte: Check that tag storage blocks are in the same zone Message-ID: References: <20231119165721.9849-1-alexandru.elisei@arm.com> <20231119165721.9849-16-alexandru.elisei@arm.com> Precedence: bulk X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi, On Fri, Nov 24, 2023 at 08:56:59PM +0100, David Hildenbrand wrote: > On 19.11.23 17:57, Alexandru Elisei wrote: > > alloc_contig_range() requires that the requested pages are in the same > > zone. Check that this is indeed the case before initializing the tag > > storage blocks. > > > > Signed-off-by: Alexandru Elisei > > --- > > arch/arm64/kernel/mte_tag_storage.c | 33 +++++++++++++++++++++++++++++ > > 1 file changed, 33 insertions(+) > > > > diff --git a/arch/arm64/kernel/mte_tag_storage.c b/arch/arm64/kernel/mte_tag_storage.c > > index 8b9bedf7575d..fd63430d4dc0 100644 > > --- a/arch/arm64/kernel/mte_tag_storage.c > > +++ b/arch/arm64/kernel/mte_tag_storage.c > > @@ -265,6 +265,35 @@ void __init mte_tag_storage_init(void) > > } > > } > > +/* alloc_contig_range() requires all pages to be in the same zone. */ > > +static int __init mte_tag_storage_check_zone(void) > > +{ > > + struct range *tag_range; > > + struct zone *zone; > > + unsigned long pfn; > > + u32 block_size; > > + int i, j; > > + > > + for (i = 0; i < num_tag_regions; i++) { > > + block_size = tag_regions[i].block_size; > > + if (block_size == 1) > > + continue; > > + > > + tag_range = &tag_regions[i].tag_range; > > + for (pfn = tag_range->start; pfn <= tag_range->end; pfn += block_size) { > > + zone = page_zone(pfn_to_page(pfn)); > > + for (j = 1; j < block_size; j++) { > > + if (page_zone(pfn_to_page(pfn + j)) != zone) { > > + pr_err("Tag storage block pages in different zones"); > > + return -EINVAL; > > + } > > + } > > + } > > + } > > + > > + return 0; > > +} > > + > > Looks like something that ordinary CMA provides. See cma_activate_area(). Indeed. > > Can't we find a way to let CMA do CMA thingies and only be a user of that? > What would be required to make the performance issue you spelled out in the > cover letter be gone and not have to open-code that in arch code? I've replied with a possible solution here [1]. [1] https://lore.kernel.org/all/ZWSvMYMjFLFZ-abv@raptor/ Thanks, Alex > > -- > Cheers, > > David / dhildenb >