From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A74936AB77 for ; Fri, 27 Feb 2026 08:53:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772182387; cv=none; b=aicSItaMAP0E03aJdco9Gxzrhax3Pk1LPadg8frk673BrcFfxWPhYrKtEZL3tiraMdIeiO89d2Hw1/7mtlMfds3omdJ9HyTiNPvQ2yGO5mEkEmKqz3SYcCR27IBsLpxu1tRYJQEPpg3z/E+8b3+bYhqqXA5cappona/ApgqSLFM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772182387; c=relaxed/simple; bh=tgLQxMu6JITyZWwdAuEZLvS6iu1D7yDVqCZzIsREeBM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=BF71kUczwKGK//1UX/vePSylATWahlOZmnu/YL4SfGancTW0MmZQ1PtlH3n52Ngwnndu5P6Hf8FDVAu7MQ/uYysCq8akMh10vZt8KcDgiYYemihqVciaPRlBqV2LkJl2cntlJB9RsgIZd/WiQ8yDzPxLbZVOM906M7qa5JhIRRU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pTd/82pF; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pTd/82pF" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D8735C116C6; Fri, 27 Feb 2026 08:52:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772182387; bh=tgLQxMu6JITyZWwdAuEZLvS6iu1D7yDVqCZzIsREeBM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=pTd/82pF246Y0dN0z7yyzx6rvF8YgPCDiBlu2mYjwr8Vxmtw9MXBDk+GtcjLU6iI1 FXgMUcBSb062z97ntKmAuoPmJOuJkgNFb/X0S7Z9eQqw2xm807wVsVMKrnsrwW3JnV 3A6jJAod0wACY5Ss84WpbLX5T1DNXL6ldRfs5j+aw1KKYgih+0GqLgn8gYqGQBAcUv EDGs0DmMKh/OnyDoT401kSjFuJ5DLvvbAQFs6XF4FwzXlj5gA23tcuWo6V3Y8/fxRF FFb9SyivscCecVcpJhyvHejyke9895NWMLBcd/EtNEvsuPxa9LM2FAKOtm9OggJz27 bwoPPsIQ94Ayg== Message-ID: <0421d482-a2b0-420c-b83f-1cc057d6662a@kernel.org> Date: Fri, 27 Feb 2026 09:52:52 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable v2 3/5] mm/khugepaged: define COLLAPSE_MAX_PTES_LIMIT as HPAGE_PMD_NR - 1 To: Nico Pache Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jackmanb@google.com, jack@suse.cz, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com References: <20260226012929.169479-1-npache@redhat.com> <20260226012929.169479-4-npache@redhat.com> <25723c0f-c702-44ad-93e9-1056313680cd@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 2/26/26 21:17, Nico Pache wrote: > On Thu, Feb 26, 2026 at 2:28 AM David Hildenbrand (Arm) > wrote: >> >> On 2/26/26 02:29, Nico Pache wrote: >>> The value (HPAGE_PMD_NR - 1) is used often in the khugepaged code to >>> signify the limit of the max_ptes_* values. Add a define for this to >>> increase code readability and reuse. >>> >>> Acked-by: Pedro Falcato >>> Reviewed-by: Zi Yan >>> Signed-off-by: Nico Pache >>> --- >>> mm/khugepaged.c | 9 +++++---- >>> 1 file changed, 5 insertions(+), 4 deletions(-) >>> >>> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >>> index 2ef4b972470b..4615f34911d1 100644 >>> --- a/mm/khugepaged.c >>> +++ b/mm/khugepaged.c >>> @@ -89,6 +89,7 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); >>> * >>> * Note that these are only respected if collapse was initiated by khugepaged. >>> */ >>> +#define COLLAPSE_MAX_PTES_LIMIT (HPAGE_PMD_NR - 1) >> >> I'd call it "KHUGEPAGED_MAX_PTES_LIMIT", because it's khugepaged >> specific (no madvise) and matches the parameters. > > Ok before changing that, note that this is also leveraged in the mTHP > set. It's technically used for madvise collapse because when it's not > khugepaged we set max_ptes_none= 511. It's more about disabling that parameter, right? -- Cheers, David