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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701366190; 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; bh=QZC2LHHmw4nzD0yHmjuZPyvBNvpTXO82fEe1JqW2iQw=; b=Uohnsr74ze8LO6vpyFSgs0ZMwnEdJPEXKSHRYlsV9qEnraUTgezs/FKpQcXBnwg8VkLVGU NnCsCPNw5QPHimUkyoZY+1AX8AMivJfH/MFvYCze8xm19gGQnrXHjKnOz+bxoTV1sGlswT 1uCYDVIZRk9MoWYjG4MHeTDoQV3HsqE= 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 0867A1756; Thu, 30 Nov 2023 09:43:56 -0800 (PST) Received: from raptor (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 526A93F6C4; Thu, 30 Nov 2023 09:43:04 -0800 (PST) Date: Thu, 30 Nov 2023 17:43:01 +0000 From: Alexandru Elisei To: Peter Collingbourne 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, steven.price@arm.com, anshuman.khandual@arm.com, vincenzo.frascino@arm.com, david@redhat.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 21/27] mm: arm64: Handle tag storage pages mapped before mprotect(PROT_MTE) Message-ID: References: <20231119165721.9849-1-alexandru.elisei@arm.com> <20231119165721.9849-22-alexandru.elisei@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 237BBA0006 X-Stat-Signature: 5jkiaspace96jazc4aykooi8tba75y1d X-HE-Tag: 1701366189-199901 X-HE-Meta: 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 Tqnqi1IQ jAb868ZWRE//jOHzKBoKY7z2wUn2MDnM2Eq4/UCeddvZqyW/v5hehvhmWU8/wjxJkwBg1nIMwDCivk3DDxfF/wtQcxLb1Dzwphm7C9/sQ4H7O8JsNbjht6+8PulPP0Jgso+VIxdo1DTKDLzLyIOfBd0uzXdUKkrtGg0ZWnfhQw+IE4nih3RLCj6v28bUN6CCVGTnkAnLhZL+AqZ70rD2+lBqrsA== 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: List-Subscribe: List-Unsubscribe: Hi Peter, On Mon, Nov 27, 2023 at 09:39:17PM -0800, Peter Collingbourne wrote: > Hi Alexandru, > > On Sun, Nov 19, 2023 at 8:59 AM Alexandru Elisei > wrote: > > > > Signed-off-by: Alexandru Elisei > > --- > > arch/arm64/include/asm/mte_tag_storage.h | 1 + > > arch/arm64/kernel/mte_tag_storage.c | 15 +++++++ > > arch/arm64/mm/fault.c | 55 ++++++++++++++++++++++++ > > include/linux/migrate.h | 8 +++- > > include/linux/migrate_mode.h | 1 + > > mm/internal.h | 6 --- > > 6 files changed, 78 insertions(+), 8 deletions(-) > > > > diff --git a/arch/arm64/include/asm/mte_tag_storage.h b/arch/arm64/include/asm/mte_tag_storage.h > > index b97406d369ce..6a8b19a6a758 100644 > > --- a/arch/arm64/include/asm/mte_tag_storage.h > > +++ b/arch/arm64/include/asm/mte_tag_storage.h > > @@ -33,6 +33,7 @@ int reserve_tag_storage(struct page *page, int order, gfp_t gfp); > > void free_tag_storage(struct page *page, int order); > > > > bool page_tag_storage_reserved(struct page *page); > > +bool page_is_tag_storage(struct page *page); > > > > vm_fault_t handle_page_missing_tag_storage(struct vm_fault *vmf); > > vm_fault_t handle_huge_page_missing_tag_storage(struct vm_fault *vmf); > > diff --git a/arch/arm64/kernel/mte_tag_storage.c b/arch/arm64/kernel/mte_tag_storage.c > > index a1cc239f7211..5096ce859136 100644 > > --- a/arch/arm64/kernel/mte_tag_storage.c > > +++ b/arch/arm64/kernel/mte_tag_storage.c > > @@ -500,6 +500,21 @@ bool page_tag_storage_reserved(struct page *page) > > return test_bit(PG_tag_storage_reserved, &page->flags); > > } > > > > +bool page_is_tag_storage(struct page *page) > > +{ > > + unsigned long pfn = page_to_pfn(page); > > + struct range *tag_range; > > + int i; > > + > > + for (i = 0; i < num_tag_regions; i++) { > > + tag_range = &tag_regions[i].tag_range; > > + if (tag_range->start <= pfn && pfn <= tag_range->end) > > + return true; > > + } > > + > > + return false; > > +} > > + > > int reserve_tag_storage(struct page *page, int order, gfp_t gfp) > > { > > unsigned long start_block, end_block; > > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > > index 6730a0812a24..964c5ae161a3 100644 > > --- a/arch/arm64/mm/fault.c > > +++ b/arch/arm64/mm/fault.c > > @@ -12,6 +12,7 @@ > > #include > > #include > > #include > > +#include > > #include > > #include > > #include > > @@ -956,6 +957,50 @@ void tag_clear_highpage(struct page *page) > > } > > > > #ifdef CONFIG_ARM64_MTE_TAG_STORAGE > > + > > +#define MR_TAGGED_TAG_STORAGE MR_ARCH_1 > > + > > +extern bool isolate_lru_page(struct page *page); > > +extern void putback_movable_pages(struct list_head *l); > > Could we move these declarations to a non-mm-internal header and > #include it instead of manually declaring them here? Yes, that's better than this hackish way of doing it. > > > + > > +/* Returns with the page reference dropped. */ > > +static void migrate_tag_storage_page(struct page *page) > > +{ > > + struct migration_target_control mtc = { > > + .nid = NUMA_NO_NODE, > > + .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_TAGGED, > > + }; > > + unsigned long i, nr_pages = compound_nr(page); > > + LIST_HEAD(pagelist); > > + int ret, tries; > > + > > + lru_cache_disable(); > > + > > + for (i = 0; i < nr_pages; i++) { > > + if (!isolate_lru_page(page + i)) { > > + ret = -EAGAIN; > > + goto out; > > + } > > + /* Isolate just grabbed another reference, drop ours. */ > > + put_page(page + i); > > + list_add_tail(&(page + i)->lru, &pagelist); > > + } > > + > > + tries = 5; > > + while (tries--) { > > + ret = migrate_pages(&pagelist, alloc_migration_target, NULL, (unsigned long)&mtc, > > + MIGRATE_SYNC, MR_TAGGED_TAG_STORAGE, NULL); > > + if (ret == 0 || ret != -EBUSY) > > This could be simplified to: > > if (ret != -EBUSY) Indeed! I can do the same thing in reserve_tag_storage(), in the loop where I call alloc_contig_range(). Thanks, Alex