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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 47E2AD2A523 for ; Wed, 16 Oct 2024 14:47:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CCB7A6B0082; Wed, 16 Oct 2024 10:47:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C7B7A6B0092; Wed, 16 Oct 2024 10:47:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B43876B0093; Wed, 16 Oct 2024 10:47:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 971AE6B0082 for ; Wed, 16 Oct 2024 10:47:00 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 4621F1205CE for ; 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s=arc-20220608; d=hostedemail.com; t=1729089875; a=rsa-sha256; cv=none; b=gBksG/XZMjwV1zhURLNUHm1HRJSIWDIBgMcJPPhOBu2hoMMVDjBPZk1kLlPzv6b9+oz7ju DWiPP5kiH9qbr9mDSWLsiXM3a/6HxSLS8EPFz2eBa26bRQSU0HG7aW4xPfWL4nQWAZkg6f QjVqAn6UdYNBiSG+gMR8+CekGS7K7u0= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf18.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com 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 8CE951007; Wed, 16 Oct 2024 07:47:27 -0700 (PDT) Received: from [10.1.28.177] (XHFQ2J9959.cambridge.arm.com [10.1.28.177]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 47B933F71E; Wed, 16 Oct 2024 07:46:55 -0700 (PDT) Message-ID: <829b5662-13c0-4728-894c-b2d578681b11@arm.com> Date: Wed, 16 Oct 2024 15:46:53 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v1 36/57] xen: Remove PAGE_SIZE compile-time constant assumption Content-Language: en-GB To: Andrew Morton , Anshuman Khandual , Ard Biesheuvel , Catalin Marinas , David Hildenbrand , Greg Marsden , Ivan Ivanov , Kalesh Singh , Marc Zyngier , Mark Rutland , Matthias Brugger , Miroslav Benes , Will Deacon , Juergen Gross , Stefano Stabellini Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org References: <20241014105514.3206191-1-ryan.roberts@arm.com> <20241014105912.3207374-1-ryan.roberts@arm.com> <20241014105912.3207374-36-ryan.roberts@arm.com> From: Ryan Roberts In-Reply-To: <20241014105912.3207374-36-ryan.roberts@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E6B661C000A X-Stat-Signature: ddd6ye66sc5dfrrxw5zd1i6ghm9qcb8k X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1729090014-359521 X-HE-Meta: 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 G0rm8SRj 3IJ6sZJNCNtWUUZfJRL5jVR5g580LaOMLvRpYYc50XqbLaENxorspdEVgVBe2QaTR5Uim6rLak/o3LGla0BqKmuEeLHrAkXD9YJc5x688EzRjdTp04PZSKpfrZ5X4Kped/ag+dAjjfy79YHsRlnig7+F2lWn4cGUgX+jcBULM8eTQbj0eRbrMytCD9ssG1R0fo1wSzmh4MdUEiCoJNFOjgRjWI/E5TOP+OaqlC+261Uuj2M+H/kTBdEHFq0QgOEoCpOx6KMHbMI3QKE80CPIlA9L5yQ== 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: + Juergen Gross, Stefano Stabellini This was a rather tricky series to get the recipients correct for and my script did not realize that "supporter" was a pseudonym for "maintainer" so you were missed off the original post. Appologies! More context in cover letter: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ On 14/10/2024 11:58, Ryan Roberts wrote: > To prepare for supporting boot-time page size selection, refactor code > to remove assumptions about PAGE_SIZE being compile-time constant. Code > intended to be equivalent when compile-time page size is active. > > Allocate enough "frame_list" static storage in the balloon driver for > the maximum supported page size. Although continue to use only the first > PAGE_SIZE of the buffer at run-time to maintain existing behaviour. > > Refactor xen_biovec_phys_mergeable() to convert ifdeffery to c if/else. > For compile-time page size, the compiler will choose one branch and > strip the dead one. For boot-time, it can be evaluated at run time. > > Refactor a BUILD_BUG_ON to evaluate the limit (when the minimum > supported page size is selected at boot-time). > > Reserve enough storage for max page size in "struct remap_data" and > "struct xenbus_map_node". > > Signed-off-by: Ryan Roberts > --- > > ***NOTE*** > Any confused maintainers may want to read the cover note here for context: > https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/ > > drivers/xen/balloon.c | 11 ++++++----- > drivers/xen/biomerge.c | 12 ++++++------ > drivers/xen/privcmd.c | 2 +- > drivers/xen/xenbus/xenbus_client.c | 5 +++-- > drivers/xen/xlate_mmu.c | 6 +++--- > include/xen/page.h | 2 ++ > 6 files changed, 21 insertions(+), 17 deletions(-) > > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 528395133b4f8..0ed5f6453af0e 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -131,7 +131,8 @@ struct balloon_stats balloon_stats; > EXPORT_SYMBOL_GPL(balloon_stats); > > /* We increase/decrease in batches which fit in a page */ > -static xen_pfn_t frame_list[PAGE_SIZE / sizeof(xen_pfn_t)]; > +static xen_pfn_t frame_list[PAGE_SIZE_MAX / sizeof(xen_pfn_t)]; > +#define FRAME_LIST_NR_ENTRIES (PAGE_SIZE / sizeof(xen_pfn_t)) > > > /* List of ballooned pages, threaded through the mem_map array. */ > @@ -389,8 +390,8 @@ static enum bp_state increase_reservation(unsigned long nr_pages) > unsigned long i; > struct page *page; > > - if (nr_pages > ARRAY_SIZE(frame_list)) > - nr_pages = ARRAY_SIZE(frame_list); > + if (nr_pages > FRAME_LIST_NR_ENTRIES) > + nr_pages = FRAME_LIST_NR_ENTRIES; > > page = list_first_entry_or_null(&ballooned_pages, struct page, lru); > for (i = 0; i < nr_pages; i++) { > @@ -434,8 +435,8 @@ static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp) > int ret; > LIST_HEAD(pages); > > - if (nr_pages > ARRAY_SIZE(frame_list)) > - nr_pages = ARRAY_SIZE(frame_list); > + if (nr_pages > FRAME_LIST_NR_ENTRIES) > + nr_pages = FRAME_LIST_NR_ENTRIES; > > for (i = 0; i < nr_pages; i++) { > page = alloc_page(gfp); > diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c > index 05a286d24f148..28f0887e40026 100644 > --- a/drivers/xen/biomerge.c > +++ b/drivers/xen/biomerge.c > @@ -8,16 +8,16 @@ > bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, > const struct page *page) > { > -#if XEN_PAGE_SIZE == PAGE_SIZE > - unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page)); > - unsigned long bfn2 = pfn_to_bfn(page_to_pfn(page)); > + if (XEN_PAGE_SIZE == PAGE_SIZE) { > + unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page)); > + unsigned long bfn2 = pfn_to_bfn(page_to_pfn(page)); > + > + return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2; > + } > > - return bfn1 + PFN_DOWN(vec1->bv_offset + vec1->bv_len) == bfn2; > -#else > /* > * XXX: Add support for merging bio_vec when using different page > * size in Xen and Linux. > */ > return false; > -#endif > } > diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c > index 9563650dfbafc..847f7b806caf7 100644 > --- a/drivers/xen/privcmd.c > +++ b/drivers/xen/privcmd.c > @@ -557,7 +557,7 @@ static long privcmd_ioctl_mmap_batch( > state.global_error = 0; > state.version = version; > > - BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0); > + BUILD_BUG_ON(((PAGE_SIZE_MIN / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE_MAX) != 0); > /* mmap_batch_fn guarantees ret == 0 */ > BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t), > &pagelist, mmap_batch_fn, &state)); > diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c > index 51b3124b0d56c..99bde836c10c4 100644 > --- a/drivers/xen/xenbus/xenbus_client.c > +++ b/drivers/xen/xenbus/xenbus_client.c > @@ -49,9 +49,10 @@ > > #include "xenbus.h" > > -#define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE)) > +#define XENBUS_PAGES(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE)) > +#define XENBUS_PAGES_MAX(_grants) (DIV_ROUND_UP(_grants, XEN_PFN_PER_PAGE_MIN)) > > -#define XENBUS_MAX_RING_PAGES (XENBUS_PAGES(XENBUS_MAX_RING_GRANTS)) > +#define XENBUS_MAX_RING_PAGES (XENBUS_PAGES_MAX(XENBUS_MAX_RING_GRANTS)) > > struct xenbus_map_node { > struct list_head next; > diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c > index f17c4c03db30c..a757c801a7542 100644 > --- a/drivers/xen/xlate_mmu.c > +++ b/drivers/xen/xlate_mmu.c > @@ -74,9 +74,9 @@ struct remap_data { > int mapped; > > /* Hypercall parameters */ > - int h_errs[XEN_PFN_PER_PAGE]; > - xen_ulong_t h_idxs[XEN_PFN_PER_PAGE]; > - xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE]; > + int h_errs[XEN_PFN_PER_PAGE_MAX]; > + xen_ulong_t h_idxs[XEN_PFN_PER_PAGE_MAX]; > + xen_pfn_t h_gpfns[XEN_PFN_PER_PAGE_MAX]; > > int h_iter; /* Iterator */ > }; > diff --git a/include/xen/page.h b/include/xen/page.h > index 285677b42943a..86683a30038a3 100644 > --- a/include/xen/page.h > +++ b/include/xen/page.h > @@ -21,6 +21,8 @@ > ((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT)) > > #define XEN_PFN_PER_PAGE (PAGE_SIZE / XEN_PAGE_SIZE) > +#define XEN_PFN_PER_PAGE_MIN (PAGE_SIZE_MIN / XEN_PAGE_SIZE) > +#define XEN_PFN_PER_PAGE_MAX (PAGE_SIZE_MAX / XEN_PAGE_SIZE) > > #define XEN_PFN_DOWN(x) ((x) >> XEN_PAGE_SHIFT) > #define XEN_PFN_UP(x) (((x) + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT)