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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <5e148194-58c2-89c2-2cd8-9f2086f1e090@nvidia.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200908_062610_963299_1DD417E1 X-CRM114-Status: GOOD ( 15.76 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki Poulose , Marc Zyngier , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, will@kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org CgpPbiAwOS8wMy8yMDIwIDExOjAxIFBNLCBSYWxwaCBDYW1wYmVsbCB3cm90ZToKPiAKPiBPbiA5 LzMvMjAgOTo1NiBBTSwgQ2F0YWxpbiBNYXJpbmFzIHdyb3RlOgo+PiBPbiBNb24sIEF1ZyAxNywg MjAyMCBhdCAwMjo0OTo0M1BNICswNTMwLCBBbnNodW1hbiBLaGFuZHVhbCB3cm90ZToKPj4+IHBt ZF9wcmVzZW50KCkgYW5kIHBtZF90cmFuc19odWdlKCkgYXJlIGV4cGVjdGVkIHRvIGJlaGF2ZSBp biB0aGUgZm9sbG93aW5nCj4+PiBtYW5uZXIgZHVyaW5nIHZhcmlvdXMgcGhhc2VzIG9mIGEgZ2l2 ZW4gUE1ELiBJdCBpcyBkZXJpdmVkIGZyb20gYSBwcmV2aW91cwo+Pj4gZGV0YWlsZWQgZGlzY3Vz c2lvbiBvbiB0aGlzIHRvcGljIFsxXSBhbmQgcHJlc2VudCBUSFAgZG9jdW1lbnRhdGlvbiBbMl0u Cj4+Pgo+Pj4gcG1kX3ByZXNlbnQocG1kKToKPj4+Cj4+PiAtIFJldHVybnMgdHJ1ZSBpZiBwbWQg cmVmZXJzIHRvIHN5c3RlbSBSQU0gd2l0aCBhIHZhbGlkIHBtZF9wYWdlKHBtZCkKPj4+IC0gUmV0 dXJucyBmYWxzZSBpZiBwbWQgZG9lcyBub3QgcmVmZXIgdG8gc3lzdGVtIFJBTSAtIEludmFsaWQg cG1kX3BhZ2UocG1kKQo+Pgo+PiBUaGUgc2Vjb25kIGJ1bGxldCBkb2Vzbid0IG1ha2UgbXVjaCBz ZW5zZS4gSWYgeW91IGhhdmUgYSBwbWQgbWFwcGluZyBvZgo+PiBzb21lIEkvTyBtZW1vcnksIHBt ZF9wcmVzZW50KCkgc3RpbGwgcmV0dXJucyB0cnVlIChhcyBkb2VzCj4+IHB0ZV9wcmVzZW50KCkp Lgo+Pgo+Pj4gZGlmZiAtLWdpdCBhL2FyY2gvYXJtNjQvaW5jbHVkZS9hc20vcGd0YWJsZS1wcm90 LmggYi9hcmNoL2FybTY0L2luY2x1ZGUvYXNtL3BndGFibGUtcHJvdC5oCj4+PiBpbmRleCA0ZDg2 N2M2NDQ2YzQuLjI4NzkyZmRkOTYyNyAxMDA2NDQKPj4+IC0tLSBhL2FyY2gvYXJtNjQvaW5jbHVk ZS9hc20vcGd0YWJsZS1wcm90LmgKPj4+ICsrKyBiL2FyY2gvYXJtNjQvaW5jbHVkZS9hc20vcGd0 YWJsZS1wcm90LmgKPj4+IEBAIC0xOSw2ICsxOSwxMyBAQAo+Pj4gwqAgI2RlZmluZSBQVEVfREVW TUFQwqDCoMKgwqDCoMKgwqAgKF9BVChwdGV2YWxfdCwgMSkgPDwgNTcpCj4+PiDCoCAjZGVmaW5l IFBURV9QUk9UX05PTkXCoMKgwqDCoMKgwqDCoCAoX0FUKHB0ZXZhbF90LCAxKSA8PCA1OCkgLyog b25seSB3aGVuICFQVEVfVkFMSUQgKi8KPj4+IMKgICsvKgo+Pj4gKyAqIFRoaXMgaGVscCBpbmRp Y2F0ZSB0aGF0IHRoZSBlbnRyeSBpcyBwcmVzZW50IGkuZSBwbWRfcGFnZSgpCj4+Cj4+IE5pdDog YWRkIGFub3RoZXIgLiBhZnRlciBpLmUKPiAKPiBBbm90aGVyIG5pdDogIlRoaXMgaGVscCBpbmRp Y2F0ZSIgPT4gIlRoaXMgaGVscGVyIGluZGljYXRlcyIKPiAKPiBNYXliZSBJIHNob3VsZCBsb29r IGF0IHRoZSBzZXJpZXMgbW9yZS4gOi0pCgpJdCBpcyB0YWxraW5nIGFib3V0IHRoZSBuZXcgUFRF IGJpdCBiZWluZyB1c2VkIGhlcmUgbm90IGFueQpoZWxwZXIuIFRob3VnaCB0aGUgZm9sbG93aW5n IHJlcGxhY2VtZW50IG1pZ2h0IGJlIGJldHRlci4KCnMvVGhpcyBoZWxwIGluZGljYXRlL1RoaXMg Yml0IGluZGljYXRlcy8KCi8qCiAqIFRoaXMgaGVscCBpbmRpY2F0ZSB0aGF0IHRoZSBlbnRyeSBp cyBwcmVzZW50IGkuZSBwbWRfcGFnZSgpCiAqIHN0aWxsIHBvaW50cyB0byBhIHZhbGlkIGh1Z2Ug cGFnZSBpbiBtZW1vcnkgZXZlbiBpZiB0aGUgcG1kCiAqIGhhcyBiZWVuIGludmFsaWRhdGVkLgog Ki8KI2RlZmluZSBQTURfUFJFU0VOVF9JTlZBTElECShfQVQocHRldmFsX3QsIDEpIDw8IDU5KSAv KiBvbmx5IHdoZW4gIVBNRF9TRUNUX1ZBTElEICovCgpfX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fXwpsaW51eC1hcm0ta2VybmVsIG1haWxpbmcgbGlzdApsaW51 eC1hcm0ta2VybmVsQGxpc3RzLmluZnJhZGVhZC5vcmcKaHR0cDovL2xpc3RzLmluZnJhZGVhZC5v cmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1hcm0ta2VybmVsCg== 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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4619CC433E2 for ; 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Tue, 8 Sep 2020 10:26:09 +0000 (UTC) X-FDA: 77239514058.28.gate17_35043e5270d4 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id 8C3866C05 for ; Tue, 8 Sep 2020 10:26:09 +0000 (UTC) X-HE-Tag: gate17_35043e5270d4 X-Filterd-Recvd-Size: 3456 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Sep 2020 10:26:09 +0000 (UTC) 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 49C7531B; Tue, 8 Sep 2020 03:26:08 -0700 (PDT) Received: from [10.163.71.211] (unknown [10.163.71.211]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id DB8153F66E; Tue, 8 Sep 2020 03:26:04 -0700 (PDT) Subject: Re: [PATCH 1/2] arm64/mm: Change THP helpers to comply with generic MM semantics To: Ralph Campbell , Catalin Marinas Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, will@kernel.org, akpm@linux-foundation.org, Mark Rutland , Marc Zyngier , Suzuki Poulose , linux-kernel@vger.kernel.org References: <1597655984-15428-1-git-send-email-anshuman.khandual@arm.com> <1597655984-15428-2-git-send-email-anshuman.khandual@arm.com> <20200903165631.GC31409@gaia> <5e148194-58c2-89c2-2cd8-9f2086f1e090@nvidia.com> From: Anshuman Khandual Message-ID: <93ef8d6a-c86a-956b-5f06-5f2e67b6fd04@arm.com> Date: Tue, 8 Sep 2020 15:55:32 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <5e148194-58c2-89c2-2cd8-9f2086f1e090@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US X-Rspamd-Queue-Id: 8C3866C05 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 Content-Transfer-Encoding: quoted-printable 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: On 09/03/2020 11:01 PM, Ralph Campbell wrote: >=20 > On 9/3/20 9:56 AM, Catalin Marinas wrote: >> On Mon, Aug 17, 2020 at 02:49:43PM +0530, Anshuman Khandual wrote: >>> pmd_present() and pmd_trans_huge() are expected to behave in the foll= owing >>> manner during various phases of a given PMD. It is derived from a pre= vious >>> detailed discussion on this topic [1] and present THP documentation [= 2]. >>> >>> pmd_present(pmd): >>> >>> - Returns true if pmd refers to system RAM with a valid pmd_page(pmd) >>> - Returns false if pmd does not refer to system RAM - Invalid pmd_pag= e(pmd) >> >> The second bullet doesn't make much sense. If you have a pmd mapping o= f >> some I/O memory, pmd_present() still returns true (as does >> pte_present()). >> >>> diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/inclu= de/asm/pgtable-prot.h >>> index 4d867c6446c4..28792fdd9627 100644 >>> --- a/arch/arm64/include/asm/pgtable-prot.h >>> +++ b/arch/arm64/include/asm/pgtable-prot.h >>> @@ -19,6 +19,13 @@ >>> =C2=A0 #define PTE_DEVMAP=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 (= _AT(pteval_t, 1) << 57) >>> =C2=A0 #define PTE_PROT_NONE=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */ >>> =C2=A0 +/* >>> + * This help indicate that the entry is present i.e pmd_page() >> >> Nit: add another . after i.e >=20 > Another nit: "This help indicate" =3D> "This helper indicates" >=20 > Maybe I should look at the series more. :-) It is talking about the new PTE bit being used here not any helper. Though the following replacement might be better. s/This help indicate/This bit indicates/ /* * This help indicate that the entry is present i.e pmd_page() * still points to a valid huge page in memory even if the pmd * has been invalidated. */ #define PMD_PRESENT_INVALID (_AT(pteval_t, 1) << 59) /* only when !PMD_SE= CT_VALID */