From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DFC501E98E3; Fri, 5 Jun 2026 17:46:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780681627; cv=none; b=FEVcFQo8OfsK7CTig7Wa4SDGa9dPgNAxM39Rlau/bR1MI/N115uzp/HFre+9NorRPUYxlHEh/TpLv94bPE/TO9r8xs5Atv/csvgpsZ/SQBO2eOsCth47apPdEwcAeHefB2Iq4c/S9p3nf1XoIM4xH84hXRf1HXnnFg7QZLo+ygk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780681627; c=relaxed/simple; bh=HFSuDbaA48MsHVvv33Gi8Gc+d2c6ZtNwEDJbbsgaWVg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=vDtmmmvWj0+SgY3BKUakESuTRSjd4Xvivrxd9DNbsr4nxgAtkpmCrdgXupUbgDlhvGQt6KGFB2edX1KGhsZKr460ys+umWTHxhyx+cyfLP0MVB5k8PZBy2rKpy6WVWWwpAWJZgDjNxNXBWLhtFEnEPhOGRle3bt2vHW8ite8nMQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Lkio3xuU; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Lkio3xuU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43EBB1F00893; Fri, 5 Jun 2026 17:46:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780681619; bh=eogvnYwd7EDRot4mePyIFCuCOhQe1D4un50SJ/87W34=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Lkio3xuUd5AU8UgtD6c6jGLmmu91MDtI3qCGmPWKBE6IYaEtIGnF9GHeQHXMlqCJ4 5JvPvUv0EkXz3IFmbmdVFNnQZ25aWUK2JMzsGxmBWYu8nbNku41yXG5xOv8FipfYdD D9pf8Fdw7S4H2c68KzK8dYzavYASaND5XbGPAVhuzklqIhvvilD7IyvfGZZs+B/6HA DZbpId7SXoZMLhYEA6v1og+j2EK3mC089lWwt7szg4fYJSBdpwH4UNaSKnioZ9/7GJ Z9C8RXPS5BOQesIkLOZBUb27B/5L0roWBlWC3kf6XEBsOSgoCMUxgk7MDxmeMC4eiR OMcDZbFBvVylQ== Date: Fri, 5 Jun 2026 18:46:44 +0100 From: Lorenzo Stoakes To: Nico Pache Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.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, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, liam@infradead.org, 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 Subject: Re: [PATCH mm-unstable v19 10/14] mm/khugepaged: introduce collapse_possible_orders helper functions Message-ID: References: <20260605161422.213817-1-npache@redhat.com> <20260605161422.213817-11-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260605161422.213817-11-npache@redhat.com> On Fri, Jun 05, 2026 at 10:14:17AM -0600, Nico Pache wrote: > Add collapse_possible_orders() to generalize THP order eligibility. The > function determines which THP orders are permitted based on collapse > context (khugepaged vs madv_collapse). We also add collapse_possible() > as a thin wrapper around collapse_possible_orders() that returns a bool > rather than the whole bitmap. > > This consolidates collapse configuration logic and provides a clean > interface for future mTHP collapse support where the orders may be > different. > > Acked-by: David Hildenbrand (Arm) > Reviewed-by: Baolin Wang > Signed-off-by: Nico Pache LGTM, so: Reviewed-by: Lorenzo Stoakes > --- > mm/khugepaged.c | 24 +++++++++++++++++++++--- > 1 file changed, 21 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 26c343a6fa3d..ec886a031952 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -554,12 +554,30 @@ void __khugepaged_enter(struct mm_struct *mm) > wake_up_interruptible(&khugepaged_wait); > } > > +/* > + * Check what orders are possible based on the vma and collapse type. > + * This is used to determine if mTHP collapse is a viable option. > + */ > +static unsigned long collapse_possible_orders(struct vm_area_struct *vma, > + vm_flags_t vm_flags, enum tva_type tva_flags) > +{ > + const unsigned long orders = BIT(HPAGE_PMD_ORDER); > + > + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); > +} > + > +static bool collapse_possible(struct vm_area_struct *vma, > + vm_flags_t vm_flags, enum tva_type tva_flags) > +{ > + return collapse_possible_orders(vma, vm_flags, tva_flags); > +} > + > void khugepaged_enter_vma(struct vm_area_struct *vma, > vm_flags_t vm_flags) > { > if (!mm_flags_test(MMF_VM_HUGEPAGE, vma->vm_mm) && > hugepage_pmd_enabled()) { > - if (thp_vma_allowable_order(vma, vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) > + if (collapse_possible(vma, vm_flags, TVA_KHUGEPAGED)) > __khugepaged_enter(vma->vm_mm); > } > } > @@ -2700,7 +2718,7 @@ static void collapse_scan_mm_slot(unsigned int progress_max, > cc->progress++; > break; > } > - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) { > + if (!collapse_possible(vma, vma->vm_flags, TVA_KHUGEPAGED)) { > cc->progress++; > continue; > } > @@ -3010,7 +3028,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsigned long start, > BUG_ON(vma->vm_start > start); > BUG_ON(vma->vm_end < end); > > - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_FORCED_COLLAPSE, PMD_ORDER)) > + if (!collapse_possible(vma, vma->vm_flags, TVA_FORCED_COLLAPSE)) > return -EINVAL; > > cc = kmalloc_obj(*cc); > -- > 2.54.0 >