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Date:   Thu, 15 Sep 2022 17:03:44 +0200
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Subject: [PATCH v7 10/43] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE
From:   Alexander Potapenko <glider@google.com>
To:     glider@google.com
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Christoph Hellwig <hch@lst.de>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Eric Biggers <ebiggers@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Kees Cook <keescook@chromium.org>,
        Marco Elver <elver@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Pekka Enberg <penberg@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Petr Mladek <pmladek@suse.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vegard Nossum <vegard.nossum@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

KMSAN adds extra metadata fields to struct page, so it does not fit into
64 bytes anymore.

This change leads to increased memory consumption of the nvdimm driver,
regardless of whether the kernel is built with KMSAN or not.

Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
---
Link: https://linux-review.googlesource.com/id/I353796acc6a850bfd7bb342aa1b63e616fc614f1
---
 drivers/nvdimm/nd.h       | 2 +-
 drivers/nvdimm/pfn_devs.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index ec5219680092d..85ca5b4da3cf3 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -652,7 +652,7 @@ void devm_namespace_disable(struct device *dev,
 		struct nd_namespace_common *ndns);
 #if IS_ENABLED(CONFIG_ND_CLAIM)
 /* max struct page size independent of kernel config */
-#define MAX_STRUCT_PAGE_SIZE 64
+#define MAX_STRUCT_PAGE_SIZE 128
 int nvdimm_setup_pfn(struct nd_pfn *nd_pfn, struct dev_pagemap *pgmap);
 #else
 static inline int nvdimm_setup_pfn(struct nd_pfn *nd_pfn,
diff --git a/drivers/nvdimm/pfn_devs.c b/drivers/nvdimm/pfn_devs.c
index 0e92ab4b32833..61af072ac98f9 100644
--- a/drivers/nvdimm/pfn_devs.c
+++ b/drivers/nvdimm/pfn_devs.c
@@ -787,7 +787,7 @@ static int nd_pfn_init(struct nd_pfn *nd_pfn)
 		 * when populating the vmemmap. This *should* be equal to
 		 * PMD_SIZE for most architectures.
 		 *
-		 * Also make sure size of struct page is less than 64. We
+		 * Also make sure size of struct page is less than 128. We
 		 * want to make sure we use large enough size here so that
 		 * we don't have a dynamic reserve space depending on
 		 * struct page size. But we also want to make sure we notice
-- 
2.37.2.789.g6183377224-goog