From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Daniel Axtens <dja@axtens.net>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Steven Price <steven.price@arm.com>,
akpm@linux-foundation.org
Cc: linux-arch@vger.kernel.org, linux-s390@vger.kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-riscv@lists.infradead.org, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v1 4/5] mm: ptdump: Support hugepd table entries
Date: Fri, 16 Apr 2021 07:25:36 +0200 [thread overview]
Message-ID: <0e7b9312-888c-2e53-b7fd-a887fd9fb429@csgroup.eu> (raw)
In-Reply-To: <87zgxzyvn3.fsf@dja-thinkpad.axtens.net>
Hi Daniel,
Le 16/04/2021 à 01:29, Daniel Axtens a écrit :
> Hi Christophe,
>
>> Which hugepd, page table entries can be at any level
>> and can be of any size.
>>
>> Add support for them.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>> mm/ptdump.c | 17 +++++++++++++++--
>> 1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/mm/ptdump.c b/mm/ptdump.c
>> index 61cd16afb1c8..6efdb8c15a7d 100644
>> --- a/mm/ptdump.c
>> +++ b/mm/ptdump.c
>> @@ -112,11 +112,24 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr,
>> {
>> struct ptdump_state *st = walk->private;
>> pte_t val = ptep_get(pte);
>> + unsigned long page_size = next - addr;
>> + int level;
>> +
>> + if (page_size >= PGDIR_SIZE)
>> + level = 0;
>> + else if (page_size >= P4D_SIZE)
>> + level = 1;
>> + else if (page_size >= PUD_SIZE)
>> + level = 2;
>> + else if (page_size >= PMD_SIZE)
>> + level = 3;
>> + else
>> + level = 4;
>>
>> if (st->effective_prot)
>> - st->effective_prot(st, 4, pte_val(val));
>> + st->effective_prot(st, level, pte_val(val));
>>
>> - st->note_page(st, addr, 4, pte_val(val), PAGE_SIZE);
>> + st->note_page(st, addr, level, pte_val(val), page_size);
>
> It seems to me that passing both level and page_size is a bit redundant,
> but I guess it does reduce the impact on each arch's code?
Exactly, as shown above, the level can be re-calculated based on the page size, but it would be a
unnecessary impact on all architectures and would duplicate the re-calculation of the level whereas
in most cases we get it for free from the caller.
>
> Kind regards,
> Daniel
>
>>
>> return 0;
>> }
>> --
>> 2.25.0
next prev parent reply other threads:[~2021-04-16 5:26 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-15 17:18 [PATCH v1 0/5] Convert powerpc to GENERIC_PTDUMP Christophe Leroy
2021-04-15 17:18 ` [PATCH v1 1/5] mm: pagewalk: Fix walk for hugepage tables Christophe Leroy
2021-04-15 22:43 ` Daniel Axtens
2021-04-16 5:48 ` Christophe Leroy
2021-04-15 17:18 ` [PATCH v1 2/5] mm: ptdump: Fix build failure Christophe Leroy
2021-04-15 17:18 ` [PATCH v1 3/5] mm: ptdump: Provide page size to notepage() Christophe Leroy
2021-04-15 23:12 ` Daniel Axtens
2021-04-16 5:19 ` Christophe Leroy
2021-04-16 9:28 ` Steven Price
2021-04-16 10:38 ` Christophe Leroy
2021-04-16 10:51 ` Steven Price
2021-04-16 11:08 ` Christophe Leroy
2021-04-16 13:00 ` Steven Price
2021-04-16 14:40 ` Christophe Leroy
2021-04-16 15:04 ` Christophe Leroy
2021-04-16 15:15 ` Christophe Leroy
2021-04-16 16:00 ` Steven Price
2021-04-19 13:14 ` Christophe Leroy
2021-04-19 14:00 ` Steven Price
2021-04-19 16:41 ` Christophe Leroy
2021-04-15 17:18 ` [PATCH v1 4/5] mm: ptdump: Support hugepd table entries Christophe Leroy
2021-04-15 23:29 ` Daniel Axtens
2021-04-16 5:25 ` Christophe Leroy [this message]
2021-04-15 17:18 ` [PATCH v1 5/5] powerpc/mm: Convert powerpc to GENERIC_PTDUMP Christophe Leroy
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