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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E9B2EC88E53 for ; Tue, 15 Sep 2026 09:02:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DDF136B0093; Tue, 15 Sep 2026 05:02:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D907A6B0095; Tue, 15 Sep 2026 05:02:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C81886B0096; Tue, 15 Sep 2026 05:02:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 9B9C16B0093 for ; Tue, 15 Sep 2026 05:02:09 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 8A39A80361 for ; Tue, 15 Sep 2026 09:02:08 +0000 (UTC) X-FDA: 85215404736.12.BB2E88B Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf22.hostedemail.com (Postfix) with ESMTP id E6C24C000C for ; Tue, 15 Sep 2026 09:02:06 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MW8hwpwx; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf22.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789462927; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=gDJQ+Dp4XqFFM9jA+QlPrk7mPj7e5HiBfLcieYIKpAo=; b=iUvoPqtBGqJUPOo89zHJM34sLPpMOQF92IX1P1MOk3lyoelRBMBklJ649lByH4elvu3tyz p9WtLoTm58ZrJfqXUoURz/G098aaxdu0NCViUVynbA61aDxJT8xOB7lOuDHIa0QzsIjBWz vqCobZy//szEWHlENDmP1qSJRY2BSVE= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789462927; b=L066Qm7zBAXoQustKGT771+48o21A+GkrXwRFRYRst3NQ9nCqY90tSax9SWX2fENxe+LsK TwW1/7Llnq7+I2YoMicltLHoVt3P/swXSYyp/UOoV9QEkmi30znvFw/7ABd0ccmZIav0Ix haJ+gchfdlVAxvC4JZaKmeVcFnmWGzs= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=MW8hwpwx; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf22.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 814F1602CC; Tue, 15 Sep 2026 09:02:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C69E91F000FF; Tue, 15 Sep 2026 09:02:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789462926; bh=gDJQ+Dp4XqFFM9jA+QlPrk7mPj7e5HiBfLcieYIKpAo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MW8hwpwxQWyiTItd2rjqwSdxeCZaHtwFUMRokpaoIrX7DjTl+xaqQB1RN9wDImwXB S7Msymu2OHWAYoza2Qx9eCGexwt4JTDSq316ER5Sayob1v8cq5aIZ92Ck3AGqYbmLx XrIDhQT2nsrhfl6AKMSe66hHWV1JCiWAEl2HgcpvWv+UvNRdlVk4PCOM9ksSbmVpe8 gA1FWSdRvFGJNBlHZHntpDh2bBjDNdbvTk//WKWw5rQ9zYr/vWrrkUHJ3O5ucU/A6d LmIQALw0VxViUcPA4tRUjG6LqlNq1scX8ynlU3xr97wemdwTKqel7oJt8AXeUtHjoK 8qTclbYIbQ1Jw== Date: Tue, 15 Sep 2026 10:01:58 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Yeoreum Yun , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Peter Xu , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Shuah Khan , Jason Gunthorpe , Leon Romanovsky , Sarthak Sharma Subject: Re: [PATCH v3 3/3] kselftest: mm: introduce size_to_shift() helper Message-ID: References: <20260914-fix_hpage_macro-v3-0-c9a305a01d39@arm.com> <20260914-fix_hpage_macro-v3-3-c9a305a01d39@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: E6C24C000C X-Stat-Signature: 7pt7tdh7bbof81k4yntceookaah4zrcu X-HE-Tag: 1789462926-204215 X-HE-Meta: U2FsdGVkX19GzGkda+9ne7A5vM89id+PI+oJ/ZTpX8xenff9kQ2G8pNl96V7zfmIpR2GeJzhFbgklIvGyf+fdhF5pufQ8lAmfGq/B2Q4BRvgizZluxIJhELTqPlOOcBxkGNpN4D4wS/PmI62Xp6bzsgFFPSS+w9j9u2FtqANYDmwFXKk0WTQDcKCf7GR0m4UnNyfYwiRP+guiiu/6D8uXeSA6ci2Nbz1TXiCGTihEDzCCNZgWFunqv3c1d5T1fGMLFwUxNLW/OtVa19eeUh7ERcXKJcywVH5akvaijKR6fKVxvqM5RPuj+qBTV0KYOw04nvlNg7/TIIy5hZwqJ2w+otZ73iiuz7ZgtTlCL3HI34hOCyKyG2iK+PuJ3kMT8nZYmuCJhuT1tlwcz5ejhUtpW2LkjoG7SSwJT4jWKW7CWZ8Hr4uS8+G/sfFTmKLVKlxxBiZlB1D+wBwP4EigcpINXnJOYfByF4q0J2+6nBzc9RgOI2do+RJ1LbbijHOZhCa+cEDMqhbDXc4G0UVhiaptI6cWVWAHYudQTzbnVQ1DcvY/ZdzZL3er2M+cOkD4LDIvvkrtDcio930zQBzcT0jyBIOASHGBjNpcTZLBp4hpthzbPaBb4D5ku7fQo7RG81tFMbh4eMxkGPOPVAXk0Odnx5e0IVdfUzFFhK7BwfOJyIy8cSL2e9MChih3jPqzlJu1PdIK3e3WvtdyjxdJaR3h/gibrzn8Afsqxe37jSha7Kk8KLwomAsltiLwuy7drgIjibdXIirpjVj5mewoQkh2Zk5WcMe029B1pc9mac6ZvBQ3LpXVPlFJK2MHxdq3dtnuSIhOMC/0Zksq+PX7coU5aXZcDqiOHi+nTi3mAc+SBG28FoXC3iX6ChKE5SLw+bajlSzHlIFZPFXM5y/w04xoIzxa5vydcn+9pzmJR8B31GUKaNxYdDuFvwBda6dFxEc+F9YHDUc1k/uodMb+BW RTkrWOrP CiHPqcO0URX/+EY/r3+B5kY4svlJLs/wrRC9P5lmtqUHm2IfBiNFxNZIeMrko3/GXlwI75zdWSG6GgBp0c7BXd8W6pnBxgrjrGXDFpTi+lqJ9JZB9ioS1oZMJ53vzSR/Nh3rUKWRqLGfUFQs45fuO9GbdxOQ70EWgYMqWMV9yAgqfrl64ZY/gTJ9Nnc/TkIc5zdipxXGMl3JUV7rQREIjf4vCrxyko7bYTimNUFr5Vu1dUE9oAXb2IVFM2sAqCOutOAf8NU1PNZa/4tByfDaIVmzCdoLDuvnvKwvvT1RJpJx9kLLiq8aqr2te3Qc/39Ctv24i0Ltor+vq63VFSdpzYzBkZpTIQXQjxPehaxxjUJxxGel+BafSLFMHd/cBK8Q2jpDY Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Sep 14, 2026 at 04:08:30PM +0200, David Hildenbrand (Arm) wrote: > On 9/14/26 16:06, Yeoreum Yun wrote: > > On Mon, Sep 14, 2026 at 04:01:02PM +0200, David Hildenbrand (Arm) wrote: > >> On 9/14/26 09:30, Yeoreum Yun wrote: > >>> Introduce size_to_shift() for future users that need to > >>> obtain shift of a huge-page which is other than pmd_psize(). > >>> > >>> Suggested-by: David Hildenbrand (Arm) > >>> Signed-off-by: Yeoreum Yun > >>> --- > >>> tools/testing/selftests/mm/vm_util.c | 10 +++++++++- > >>> tools/testing/selftests/mm/vm_util.h | 1 + > >>> 2 files changed, 10 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > >>> index fd1432dc6152..1fef1266429f 100644 > >>> --- a/tools/testing/selftests/mm/vm_util.c > >>> +++ b/tools/testing/selftests/mm/vm_util.c > >>> @@ -157,6 +157,14 @@ bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len) > >>> return false; > >>> } > >>> Probably worth a comment here saying it's only for power-of-two sizes. > >>> +uint64_t size_to_shift(uint64_t size) > >>> +{ > >>> + if (__builtin_popcountll(size) != 1) I wonder if it wouldn't be better to just do the old trick of: if (!size || (size & (size - 1))) return 0; ? > >>> + return 0; > >>> + > >>> + return ffsl(size) - 1; > >>> +} > >> > >> Could likely just be an inline helper? > > > > Okay. If there is no comments on today, I'll post tomorrow with this. > > > > No need to rush, leave some more days for people to catch up. Agree with David seems better as an inline thing, the __builtin_xxx() should be... built-in hopefully :P though I suggest something that wouldn't need that. As long as strings.h is included in the header ofc for ffsl(). With the stuff above addressed, seems fine to me so: Reviewed-by: Lorenzo Stoakes (ARM) > > -- > Cheers, > > David -- Cheers, Lorenzo