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b=nOqke5uHz3c8Omr8Fn2jbW5MHHG5OuPLMw1lLfed1JGaFfykgXJjuqzL1Hi+4WtoG +jBvLMTkMO1mVi4JSWlb6t2S4RsyCiq1zpMPMbbpxzeU7XAO4F2eUlYJM72UZcmZL+ u1z923V6dbF2O4hgLytDjQISNB8FtPCew/kW7K9UCjrqkX0VZhX+xsAKN/GSUvUxFu jF9+3tI1AUG764wYWaMQ1Bi0bgL4Akk+KL/qH7U6sGl9TR34BpOrqoFymyLNhC5576 WhHptdIK9xAkNPvKggauQNvE7aW/o+HhQrqkCUm3XWvORXkEylaRApJRREPATEeb94 WRcgh8sTsEksA== Message-ID: <7f850a9a-0ac8-473d-a4ec-914462e4014d@kernel.org> Date: Thu, 12 Mar 2026 22:09:04 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable v15 09/13] mm/khugepaged: introduce collapse_allowable_orders helper function To: Nico Pache , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org Cc: 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, jack@suse.cz, jackmanb@google.com, 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: <20260226031741.230674-1-npache@redhat.com> <20260226032542.233891-1-npache@redhat.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: DACEA20004 X-Rspamd-Server: rspam08 X-Stat-Signature: ff558364myseth56age85pcd77tryt8q X-HE-Tag: 1773349762-429320 X-HE-Meta: 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 aT2RWxmg o/DeWay280QxRlgr6QN03p+v9y9Z/bgRr5ex/e6gbWHBGoQbSZ85xvtquqC2yQtg34LNAksP/qpxgrLk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/26/26 04:25, Nico Pache wrote: > Add collapse_allowable_orders() to generalize THP order eligibility. The > function determines which THP orders are permitted based on collapse > context (khugepaged vs madv_collapse). > > This consolidates collapse configuration logic and provides a clean > interface for future mTHP collapse support where the orders may be > different. > > Reviewed-by: Baolin Wang > Signed-off-by: Nico Pache > --- > mm/khugepaged.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 2e66d660ee8e..2fdfb6d42cf9 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -486,12 +486,22 @@ static unsigned int collapse_max_ptes_none(unsigned int order) > return -EINVAL; > } > > +/* Check what orders are allowed based on the vma and collapse type */ > +static unsigned long collapse_allowable_orders(struct vm_area_struct *vma, > + vm_flags_t vm_flags, bool is_khugepaged) Nit: one tab to much > +{ > + enum tva_type tva_flags = is_khugepaged ? TVA_KHUGEPAGED : TVA_FORCED_COLLAPSE; > + unsigned long orders = BIT(HPAGE_PMD_ORDER); > + > + return thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); > +} > + > 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_allowable_orders(vma, vm_flags, /*is_khugepaged=*/true)) > __khugepaged_enter(vma->vm_mm); > } > } > @@ -2637,7 +2647,7 @@ static unsigned int collapse_scan_mm_slot(unsigned int pages, enum scan_result * > progress++; > break; > } > - if (!thp_vma_allowable_order(vma, vma->vm_flags, TVA_KHUGEPAGED, PMD_ORDER)) { > + if (!collapse_allowable_orders(vma, vma->vm_flags, /*is_khugepaged=*/true)) { I'm not sure if converting from a perfectly readable enum to a boolean is an improvement? I would just keep the TVA_KHUGEPAGED / TVA_FORCED_COLLAPSE here/ If you want to catch callers passing in something else, you could likely use a BUILD_BUG_ON in there. -- Cheers, David