From: Qi Zheng <zhengqi.arch@bytedance.com>
To: Vishal Moola <vishal.moola@gmail.com>
Cc: akpm@linux-foundation.org, hughd@google.com, david@redhat.com,
rppt@kernel.org, willy@infradead.org, muchun.song@linux.dev,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Janosch Frank <frankja@linux.ibm.com>,
Claudio Imbrenda <imbrenda@linux.ibm.com>,
kvm@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH 3/3] s390: supplement for ptdesc conversion
Date: Wed, 27 Mar 2024 10:11:13 +0800 [thread overview]
Message-ID: <7258d29d-0d4b-4463-8685-e3f21d426d2d@bytedance.com> (raw)
In-Reply-To: <ZgMmec2paNA0GFwY@fedora>
On 2024/3/27 03:48, Vishal Moola wrote:
> On Mon, Mar 04, 2024 at 07:07:20PM +0800, Qi Zheng wrote:
>> --- a/arch/s390/mm/gmap.c
>> +++ b/arch/s390/mm/gmap.c
>> @@ -206,9 +206,11 @@ static void gmap_free(struct gmap *gmap)
>>
>> /* Free additional data for a shadow gmap */
>> if (gmap_is_shadow(gmap)) {
>> + struct ptdesc *ptdesc;
>> +
>> /* Free all page tables. */
>> - list_for_each_entry_safe(page, next, &gmap->pt_list, lru)
>> - page_table_free_pgste(page);
>> + list_for_each_entry_safe(ptdesc, next, &gmap->pt_list, pt_list)
>> + page_table_free_pgste(ptdesc);
>
> An important note: ptdesc allocation/freeing is different than the
> standard alloc_pages()/free_pages() routines architectures are used to.
> Are we sure we don't have memory leaks here?
>
> We always allocate and free ptdescs as compound pages; for page table
> struct pages, most archictectures do not. s390 has CRST_ALLOC_ORDER
> pagetables, meaning if we free anything using the ptdesc api, we better
> be sure it was allocated using the ptdesc api as well.
According to the code inspection, all ptdescs added to the pmap->pt_list
are allocated via page_table_alloc_pgste().
>
> Like you, I don't have a s390 to test on, so hopefully some s390 expert
> can chime in to let us know if we need a fix for this.
Yes, hope so!
prev parent reply other threads:[~2024-03-27 2:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1709541697.git.zhengqi.arch@bytedance.com>
2024-03-04 11:07 ` [PATCH 3/3] s390: supplement for ptdesc conversion Qi Zheng
2024-03-05 7:21 ` [PATCH v2 " Qi Zheng
2024-03-26 7:46 ` Heiko Carstens
2024-03-26 19:48 ` [PATCH " Vishal Moola
2024-03-27 2:11 ` Qi Zheng [this message]
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