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X-CSE-ConnectionGUID: TqxAGj1wSda+VGBajRT0aQ== X-CSE-MsgGUID: 5b9Wh10cQtOTLPyMz/GCyA== X-IronPort-AV: E=McAfee;i="6700,10204,11446"; a="61098598" X-IronPort-AV: E=Sophos;i="6.15,320,1739865600"; d="scan'208";a="61098598" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2025 01:55:26 -0700 X-CSE-ConnectionGUID: 1yTLA9bhTNGc1WfrftagLg== X-CSE-MsgGUID: YJGTweprTPmbgT0LpLaE6Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,320,1739865600"; d="scan'208";a="166357521" Received: from unknown (HELO [10.238.3.95]) ([10.238.3.95]) by fmviesa002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 May 2025 01:55:08 -0700 Message-ID: Date: Wed, 28 May 2025 16:55:05 +0800 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: [RFC PATCH v2 16/51] mm: hugetlb: Consolidate interpretation of gbl_chg within alloc_hugetlb_folio() To: Ackerley Tng Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-fsdevel@vger.kernel.org, aik@amd.com, ajones@ventanamicro.com, akpm@linux-foundation.org, amoorthy@google.com, anthony.yznaga@oracle.com, anup@brainfault.org, aou@eecs.berkeley.edu, bfoster@redhat.com, brauner@kernel.org, catalin.marinas@arm.com, chao.p.peng@intel.com, chenhuacai@kernel.org, dave.hansen@intel.com, david@redhat.com, dmatlack@google.com, dwmw@amazon.co.uk, erdemaktas@google.com, fan.du@intel.com, fvdl@google.com, graf@amazon.com, haibo1.xu@intel.com, hch@infradead.org, hughd@google.com, ira.weiny@intel.com, isaku.yamahata@intel.com, jack@suse.cz, james.morse@arm.com, jarkko@kernel.org, jgg@ziepe.ca, jgowans@amazon.com, jhubbard@nvidia.com, jroedel@suse.de, jthoughton@google.com, jun.miao@intel.com, kai.huang@intel.com, keirf@google.com, kent.overstreet@linux.dev, kirill.shutemov@intel.com, liam.merwick@oracle.com, maciej.wieczor-retman@intel.com, mail@maciej.szmigiero.name, maz@kernel.org, mic@digikod.net, michael.roth@amd.com, mpe@ellerman.id.au, muchun.song@linux.dev, nikunj@amd.com, nsaenz@amazon.es, oliver.upton@linux.dev, palmer@dabbelt.com, pankaj.gupta@amd.com, paul.walmsley@sifive.com, pbonzini@redhat.com, pdurrant@amazon.co.uk, peterx@redhat.com, pgonda@google.com, pvorel@suse.cz, qperret@google.com, quic_cvanscha@quicinc.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, quic_svaddagi@quicinc.com, quic_tsoni@quicinc.com, richard.weiyang@gmail.com, rick.p.edgecombe@intel.com, rientjes@google.com, roypat@amazon.co.uk, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, steven.sistare@oracle.com, suzuki.poulose@arm.com, tabba@google.com, thomas.lendacky@amd.com, usama.arif@bytedance.com, vannapurve@google.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, vkuznets@redhat.com, wei.w.wang@intel.com, will@kernel.org, willy@infradead.org, xiaoyao.li@intel.com, yan.y.zhao@intel.com, yilun.xu@intel.com, yuzenghui@huawei.com, zhiquan1.li@intel.com References: <8548af334e01401a776aae37a0e9f30f9ffbba8c.1747264138.git.ackerleytng@google.com> Content-Language: en-US From: Binbin Wu In-Reply-To: <8548af334e01401a776aae37a0e9f30f9ffbba8c.1747264138.git.ackerleytng@google.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/15/2025 7:41 AM, Ackerley Tng wrote: > Previously, gbl_chg was passed from alloc_hugetlb_folio() into > dequeue_hugetlb_folio_vma(), leaking the concept of gbl_chg into > dequeue_hugetlb_folio_vma(). > > This patch consolidates the interpretation of gbl_chg into > alloc_hugetlb_folio(), also renaming dequeue_hugetlb_folio_vma() to > dequeue_hugetlb_folio() so dequeue_hugetlb_folio() can just focus on > dequeuing a folio. > > Change-Id: I31bf48af2400b6e13b44d03c8be22ce1a9092a9c > Signed-off-by: Ackerley Tng > --- > mm/hugetlb.c | 28 +++++++++++----------------- > 1 file changed, 11 insertions(+), 17 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 6ea1be71aa42..b843e869496f 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1364,9 +1364,9 @@ static unsigned long available_huge_pages(struct hstate *h) > return h->free_huge_pages - h->resv_huge_pages; > } > > -static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, > - struct vm_area_struct *vma, > - unsigned long address, long gbl_chg) > +static struct folio *dequeue_hugetlb_folio(struct hstate *h, > + struct vm_area_struct *vma, > + unsigned long address) The rename seems not needed in this patch, since the function still takes vma and uses it. May be better to move the rename to a later patch. > { > struct folio *folio = NULL; > struct mempolicy *mpol; > @@ -1374,13 +1374,6 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, > nodemask_t *nodemask; > int nid; > > - /* > - * gbl_chg==1 means the allocation requires a new page that was not > - * reserved before. Making sure there's at least one free page. > - */ > - if (gbl_chg && !available_huge_pages(h)) > - goto err; > - > gfp_mask = htlb_alloc_mask(h); > nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); > > @@ -1398,9 +1391,6 @@ static struct folio *dequeue_hugetlb_folio_vma(struct hstate *h, > > mpol_cond_put(mpol); > return folio; > - > -err: > - return NULL; > } > > /* > @@ -3074,12 +3064,16 @@ struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, > goto out_uncharge_cgroup_reservation; > > spin_lock_irq(&hugetlb_lock); > + > /* > - * glb_chg is passed to indicate whether or not a page must be taken > - * from the global free pool (global change). gbl_chg == 0 indicates > - * a reservation exists for the allocation. > + * gbl_chg == 0 indicates a reservation exists for the allocation - so > + * try dequeuing a page. If there are available_huge_pages(), try using > + * them! > */ > - folio = dequeue_hugetlb_folio_vma(h, vma, addr, gbl_chg); > + folio = NULL; > + if (!gbl_chg || available_huge_pages(h)) > + folio = dequeue_hugetlb_folio(h, vma, addr); > + > if (!folio) { > spin_unlock_irq(&hugetlb_lock); > folio = alloc_buddy_hugetlb_folio_with_mpol(h, vma, addr);