From: Muchun Song <songmuchun@bytedance.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>,
Mike Kravetz <mike.kravetz@oracle.com>,
Thomas Gleixner <tglx@linutronix.de>,
mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
dave.hansen@linux.intel.com, luto@kernel.org,
Peter Zijlstra <peterz@infradead.org>,
viro@zeniv.linux.org.uk,
Andrew Morton <akpm@linux-foundation.org>,
paulmck@kernel.org, mchehab+huawei@kernel.org,
pawan.kumar.gupta@linux.intel.com,
Randy Dunlap <rdunlap@infradead.org>,
oneukum@suse.com, anshuman.khandual@arm.com, jroedel@suse.de,
Mina Almasry <almasrymina@google.com>,
David Rientjes <rientjes@google.com>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Xiongchun duan <duanxiongchun@bytedance.com>,
linux-doc@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [External] Re: [PATCH v3 05/21] mm/hugetlb: Introduce pgtable allocation/freeing helpers
Date: Tue, 10 Nov 2020 14:08:46 +0800 [thread overview]
Message-ID: <CAMZfGtWbGETq=3b5i0aentemXkZn2J2DNWu05mBs=4L8bJm1jg@mail.gmail.com> (raw)
In-Reply-To: <20201110054250.GA2906@localhost.localdomain>
On Tue, Nov 10, 2020 at 1:42 PM Oscar Salvador <osalvador@suse.de> wrote:
>
> On Tue, Nov 10, 2020 at 11:49:27AM +0800, Muchun Song wrote:
> > On Tue, Nov 10, 2020 at 1:21 AM Oscar Salvador <osalvador@suse.de> wrote:
> > >
> > > On Sun, Nov 08, 2020 at 10:10:57PM +0800, Muchun Song wrote:
> > > > +static inline unsigned int pgtable_pages_to_prealloc_per_hpage(struct hstate *h)
> > > > +{
> > > > + unsigned long vmemmap_size = vmemmap_pages_size_per_hpage(h);
> > > > +
> > > > + /*
> > > > + * No need pre-allocate page tabels when there is no vmemmap pages
> > > > + * to free.
> > > s /tabels/tables/
> >
> > Thanks.
> >
> > >
> > > > +static int vmemmap_pgtable_prealloc(struct hstate *h, struct page *page)
> > > > +{
> > > > + int i;
> > > > + pgtable_t pgtable;
> > > > + unsigned int nr = pgtable_pages_to_prealloc_per_hpage(h);
> > > > +
> > > > + if (!nr)
> > > > + return 0;
> > > > +
> > > > + vmemmap_pgtable_init(page);
> > > > +
> > > > + for (i = 0; i < nr; i++) {
> > > > + pte_t *pte_p;
> > > > +
> > > > + pte_p = pte_alloc_one_kernel(&init_mm);
> > > > + if (!pte_p)
> > > > + goto out;
> > > > + vmemmap_pgtable_deposit(page, virt_to_page(pte_p));
> > > > + }
> > > > +
> > > > + return 0;
> > > > +out:
> > > > + while (i-- && (pgtable = vmemmap_pgtable_withdraw(page)))
> > > > + pte_free_kernel(&init_mm, page_to_virt(pgtable));
> > >
> > > would not be enough to:
> > >
> > > while (pgtable = vmemmap_pgtable_withdrag(page))
> > > pte_free_kernel(&init_mm, page_to_virt(pgtable));
> >
> > The vmemmap_pgtable_withdraw can not return NULL. So we can not
> > drop the "i--".
>
> Yeah, you are right, I managed to confuse myself.
> But why not make it return null, something like:
>
> static pgtable_t vmemmap_pgtable_withdraw(struct page *page)
> {
> pgtable_t pgtable;
>
> /* FIFO */
> pgtable = page_huge_pte(page);
The check should be added here.
if (!pgtable)
return NULL;
Just like my previous v2 patch does. In this case, we can drop those
checks. What do you think?
> page_huge_pte(page) = list_first_entry_or_null(&pgtable->lru,
> struct page, lru);
> if (page_huge_pte(page))
> list_del(&pgtable->lru);
>
> return page_huge_pte(page) ? pgtable : NULL;
> }
>
> What do you think?
>
>
> --
> Oscar Salvador
> SUSE L3
--
Yours,
Muchun
next prev parent reply other threads:[~2020-11-10 6:09 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-08 14:10 [PATCH v3 00/21] Free some vmemmap pages of hugetlb page Muchun Song
2020-11-08 14:10 ` [PATCH v3 01/21] mm/memory_hotplug: Move bootmem info registration API to bootmem_info.c Muchun Song
2020-11-08 14:10 ` [PATCH v3 02/21] mm/memory_hotplug: Move {get,put}_page_bootmem() " Muchun Song
2020-11-08 14:10 ` [PATCH v3 03/21] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2020-11-09 13:52 ` Oscar Salvador
2020-11-09 14:20 ` [External] " Muchun Song
2020-11-10 19:31 ` Mike Kravetz
2020-11-10 19:50 ` Matthew Wilcox
2020-11-10 20:30 ` Mike Kravetz
2020-11-17 15:35 ` [External] " Muchun Song
2020-11-11 3:28 ` Muchun Song
2020-11-08 14:10 ` [PATCH v3 04/21] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2020-11-09 16:48 ` Oscar Salvador
2020-11-10 2:42 ` [External] " Muchun Song
2020-11-10 19:38 ` Mike Kravetz
2020-11-11 3:22 ` Muchun Song
2020-11-08 14:10 ` [PATCH v3 05/21] mm/hugetlb: Introduce pgtable allocation/freeing helpers Muchun Song
2020-11-09 17:21 ` Oscar Salvador
2020-11-10 3:49 ` [External] " Muchun Song
2020-11-10 5:42 ` Oscar Salvador
2020-11-10 6:08 ` Muchun Song [this message]
2020-11-10 6:33 ` Oscar Salvador
2020-11-10 7:10 ` Muchun Song
2020-11-11 0:47 ` Mike Kravetz
2020-11-11 3:41 ` [External] " Muchun Song
2020-11-13 0:35 ` Mike Kravetz
2020-11-13 1:02 ` Mike Kravetz
2020-11-13 4:18 ` Muchun Song
2020-11-08 14:10 ` [PATCH v3 06/21] mm/bootmem_info: Introduce {free,prepare}_vmemmap_page() Muchun Song
2020-11-08 14:10 ` [PATCH v3 07/21] mm/bootmem_info: Combine bootmem info and type into page->freelist Muchun Song
2020-11-08 14:11 ` [PATCH v3 08/21] mm/vmemmap: Initialize page table lock for vmemmap Muchun Song
2020-11-09 18:11 ` Oscar Salvador
2020-11-10 5:17 ` [External] " Muchun Song
2020-11-08 14:11 ` [PATCH v3 09/21] mm/hugetlb: Free the vmemmap pages associated with each hugetlb page Muchun Song
2020-11-09 18:51 ` Oscar Salvador
2020-11-10 6:40 ` [External] " Muchun Song
2020-11-10 9:48 ` Oscar Salvador
2020-11-10 10:47 ` Muchun Song
2020-11-10 13:52 ` Oscar Salvador
2020-11-10 14:00 ` Muchun Song
2020-11-08 14:11 ` [PATCH v3 10/21] mm/hugetlb: Defer freeing of hugetlb pages Muchun Song
2020-11-08 14:11 ` [PATCH v3 11/21] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page Muchun Song
2020-11-08 14:11 ` [PATCH v3 12/21] mm/hugetlb: Introduce remap_huge_page_pmd_vmemmap helper Muchun Song
2020-11-08 14:11 ` [PATCH v3 13/21] mm/hugetlb: Use PG_slab to indicate split pmd Muchun Song
2020-11-08 14:11 ` [PATCH v3 14/21] mm/hugetlb: Support freeing vmemmap pages of gigantic page Muchun Song
2020-11-08 14:11 ` [PATCH v3 15/21] mm/hugetlb: Add a BUILD_BUG_ON to check if struct page size is a power of two Muchun Song
2020-11-08 14:11 ` [PATCH v3 16/21] mm/hugetlb: Set the PageHWPoison to the raw error page Muchun Song
2020-11-08 14:11 ` [PATCH v3 17/21] mm/hugetlb: Flush work when dissolving hugetlb page Muchun Song
2020-11-08 14:11 ` [PATCH v3 18/21] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap Muchun Song
2020-11-08 14:11 ` [PATCH v3 19/21] mm/hugetlb: Merge pte to huge pmd only for gigantic page Muchun Song
2020-11-08 14:11 ` [PATCH v3 20/21] mm/hugetlb: Gather discrete indexes of tail page Muchun Song
2020-11-08 14:11 ` [PATCH v3 21/21] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page Muchun Song
2020-11-10 19:23 ` [PATCH v3 00/21] Free some vmemmap pages of hugetlb page Mike Kravetz
2020-11-11 3:21 ` [External] " Muchun Song
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