From: Oscar Salvador <osalvador@suse.de>
To: Muchun Song <songmuchun@bytedance.com>
Cc: "Mike Kravetz" <mike.kravetz@oracle.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"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>,
"Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
"David Hildenbrand" <david@redhat.com>,
"HORIGUCHI NAOYA(堀口 直也)" <naoya.horiguchi@nec.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 v12 04/13] mm/hugetlb: Free the vmemmap pages associated with each HugeTLB page
Date: Thu, 14 Jan 2021 12:52:48 +0100 [thread overview]
Message-ID: <20210114115248.GA24592@localhost.localdomain> (raw)
In-Reply-To: <CAMZfGtUhhMDCaZKeayS1+w0MvBijDZC2AiUV4z5rUFrfbXBefw@mail.gmail.com>
On Thu, Jan 14, 2021 at 06:54:30PM +0800, Muchun Song wrote:
> I think this approach may be only suitable for generic huge page only.
> So we can implement it only for huge page.
>
> Hi Oscar,
>
> What's your opinion about this?
I tried something like:
static void vmemmap_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end,
struct vmemmap_remap_walk *walk)
{
pte_t *pte;
pte = pte_offset_kernel(pmd, addr);
if (!walk->reuse_page) {
BUG_ON(pte_none(*pte));
walk->reuse_page = pte_page(*pte++);
addr = walk->remap_start;
}
for (; addr != end; addr += PAGE_SIZE, pte++) {
BUG_ON(pte_none(*pte));
walk->remap_pte(pte, addr, walk);
}
}
void vmemmap_remap_free(unsigned long start, unsigned long end,
unsigned long reuse)
{
LIST_HEAD(vmemmap_pages);
struct vmemmap_remap_walk walk = {
.remap_pte = vmemmap_remap_pte,
.reuse_addr = reuse,
.remap_start = start,
.vmemmap_pages = &vmemmap_pages,
};
BUG_ON(start != reuse + PAGE_SIZE);
vmemmap_remap_range(reuse, end, &walk);
free_vmemmap_page_list(&vmemmap_pages);
}
but it might overcomplicate things and I am not sure it is any better.
So I am fine with keeping it as is.
Should another user come in the future, we can always revisit.
Maybe just add a little comment in vmemmap_pte_range(), explaining while we
are "+= PAGE_SIZE" for address and I would like to see a comment in
vmemmap_remap_free why the BUG_ON and more important what it is checking.
--
Oscar Salvador
SUSE L3
next prev parent reply other threads:[~2021-01-14 11:53 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-06 14:19 [PATCH v12 00/13] Free some vmemmap pages of HugeTLB page Muchun Song
2021-01-06 14:19 ` [PATCH v12 01/13] mm/memory_hotplug: Factor out bootmem core functions to bootmem_info.c Muchun Song
2021-01-06 14:19 ` [PATCH v12 02/13] mm/hugetlb: Introduce a new config HUGETLB_PAGE_FREE_VMEMMAP Muchun Song
2021-01-06 14:19 ` [PATCH v12 03/13] mm: Introduce VM_WARN_ON_PAGE macro Muchun Song
2021-01-13 22:30 ` Mike Kravetz
2021-01-14 2:50 ` [External] " Muchun Song
2021-01-06 14:19 ` [PATCH v12 04/13] mm/hugetlb: Free the vmemmap pages associated with each HugeTLB page Muchun Song
2021-01-12 8:04 ` Oscar Salvador
2021-01-12 11:33 ` [External] " Muchun Song
2021-01-13 9:20 ` Oscar Salvador
2021-01-13 23:27 ` Mike Kravetz
2021-01-14 10:54 ` Muchun Song
2021-01-14 11:52 ` Oscar Salvador [this message]
2021-01-14 13:05 ` Muchun Song
2021-01-14 10:57 ` Muchun Song
2021-01-06 14:19 ` [PATCH v12 05/13] mm/hugetlb: Defer freeing of HugeTLB pages Muchun Song
2021-01-06 14:19 ` [PATCH v12 06/13] mm/hugetlb: Allocate the vmemmap pages associated with each HugeTLB page Muchun Song
2021-01-06 14:19 ` [PATCH v12 07/13] mm/hugetlb: Set the PageHWPoison to the raw error page Muchun Song
2021-01-06 14:19 ` [PATCH v12 08/13] mm/hugetlb: Flush work when dissolving a HugeTLB page Muchun Song
2021-01-06 14:19 ` [PATCH v12 09/13] mm/hugetlb: Introduce PageHugeInflight Muchun Song
2021-01-06 14:19 ` [PATCH v12 10/13] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap Muchun Song
2021-01-06 14:19 ` [PATCH v12 11/13] mm/hugetlb: Introduce nr_free_vmemmap_pages in the struct hstate Muchun Song
2021-01-06 14:19 ` [PATCH v12 12/13] mm/hugetlb: Gather discrete indexes of tail page Muchun Song
2021-01-14 0:18 ` Mike Kravetz
2021-01-14 2:47 ` [External] " Muchun Song
2021-01-06 14:19 ` [PATCH v12 13/13] mm/hugetlb: Optimize the code with the help of the compiler Muchun Song
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