| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <36747b09-8141-019f-85dd-59f3d4623ec1@linux.alibaba.com>
Date: Mon, 10 Jul 2023 17:26:51 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: "Huang, Ying" <ying.huang@...el.com>
Cc: akpm@...ux-foundation.org, mgorman@...hsingularity.net,
vbabka@...e.cz, david@...hat.com, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mm: compaction: skip the memory hole rapidly when
isolating free pages
On 7/10/2023 2:11 PM, Huang, Ying wrote:
> Baolin Wang <baolin.wang@...ux.alibaba.com> writes:
>
>> On my machine with below memory layout, and I can see it will take more
>> time to skip the larger memory hole (range: 0x100000000 - 0x1800000000)
>> when isolating free pages. So adding a new helper to skip the memory
>> hole rapidly, which can reduce the time consumed from about 70us to less
>> than 1us.
>>
>> [ 0.000000] Zone ranges:
>> [ 0.000000] DMA [mem 0x0000000040000000-0x00000000ffffffff]
>> [ 0.000000] DMA32 empty
>> [ 0.000000] Normal [mem 0x0000000100000000-0x0000001fa7ffffff]
>
> The memory hole is at the beginning of zone NORMAL? If so, should zone
No, the memory hole range is 0x1000000000 - 0x1800000000, and the normal
zone is start from 0x100000000.
I'm sorry I made a typo in the commit message, which confuses you. The
memory hole range should be: 0x1000000000 - 0x1800000000. I updated the
commit message to the following and addressed David's comment:
"
Just like commit 9721fd82351d ("mm: compaction: skip memory hole rapidly
when isolating migratable pages"), I can see it will also take more
time to skip the larger memory hole (range: 0x1000000000 - 0x1800000000)
when isolating free pages on my machine with below memory layout. So
like commit 9721fd82351d, adding a new helper to skip the memory hole
rapidly, which can reduce the time consumed from about 70us to less than
1us.
[ 0.000000] Zone ranges:
[ 0.000000] DMA [mem 0x0000000040000000-0x00000000ffffffff]
[ 0.000000] DMA32 empty
[ 0.000000] Normal [mem 0x0000000100000000-0x0000001fa7ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000040000000-0x0000000fffffffff]
[ 0.000000] node 0: [mem 0x0000001800000000-0x0000001fa3c7ffff]
[ 0.000000] node 0: [mem 0x0000001fa3c80000-0x0000001fa3ffffff]
[ 0.000000] node 0: [mem 0x0000001fa4000000-0x0000001fa402ffff]
[ 0.000000] node 0: [mem 0x0000001fa4030000-0x0000001fa40effff]
[ 0.000000] node 0: [mem 0x0000001fa40f0000-0x0000001fa73cffff]
[ 0.000000] node 0: [mem 0x0000001fa73d0000-0x0000001fa745ffff]
[ 0.000000] node 0: [mem 0x0000001fa7460000-0x0000001fa746ffff]
[ 0.000000] node 0: [mem 0x0000001fa7470000-0x0000001fa758ffff]
[ 0.000000] node 0: [mem 0x0000001fa7590000-0x0000001fa7ffffff]
"
> NORMAL start at 0x1800000000? And, the free pages will not be scanned
> there? Or my understanding were wrong. >
>> [ 0.000000] Movable zone start for each node
>> [ 0.000000] Early memory node ranges
>> [ 0.000000] node 0: [mem 0x0000000040000000-0x0000000fffffffff]
>> [ 0.000000] node 0: [mem 0x0000001800000000-0x0000001fa3c7ffff]
>> [ 0.000000] node 0: [mem 0x0000001fa3c80000-0x0000001fa3ffffff]
>> [ 0.000000] node 0: [mem 0x0000001fa4000000-0x0000001fa402ffff]
>> [ 0.000000] node 0: [mem 0x0000001fa4030000-0x0000001fa40effff]
>> [ 0.000000] node 0: [mem 0x0000001fa40f0000-0x0000001fa73cffff]
>> [ 0.000000] node 0: [mem 0x0000001fa73d0000-0x0000001fa745ffff]
>> [ 0.000000] node 0: [mem 0x0000001fa7460000-0x0000001fa746ffff]
>> [ 0.000000] node 0: [mem 0x0000001fa7470000-0x0000001fa758ffff]
>> [ 0.000000] node 0: [mem 0x0000001fa7590000-0x0000001fa7ffffff]
>>
>> Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
>> ---
>> mm/compaction.c | 30 +++++++++++++++++++++++++++++-
>> 1 file changed, 29 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/compaction.c b/mm/compaction.c
>> index 43358efdbdc2..9641e2131901 100644
>> --- a/mm/compaction.c
>> +++ b/mm/compaction.c
>> @@ -249,11 +249,31 @@ static unsigned long skip_offline_sections(unsigned long start_pfn)
>>
>> return 0;
>> }
>> +
>> +static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
>> +{
>> + unsigned long start_nr = pfn_to_section_nr(start_pfn);
>> +
>> + if (!start_nr || online_section_nr(start_nr))
>> + return 0;
>> +
>> + while (start_nr-- > 0) {
>> + if (online_section_nr(start_nr))
>> + return section_nr_to_pfn(start_nr) + PAGES_PER_SECTION - 1;
>> + }
>> +
>> + return 0;
>> +}
>> #else
>> static unsigned long skip_offline_sections(unsigned long start_pfn)
>> {
>> return 0;
>> }
>> +
>> +static unsigned long skip_offline_sections_reverse(unsigned long start_pfn)
>> +{
>> + return 0;
>> +}
>> #endif
>>
>> /*
>> @@ -1668,8 +1688,16 @@ static void isolate_freepages(struct compact_control *cc)
>>
>> page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn,
>> zone);
>> - if (!page)
>> + if (!page) {
>> + unsigned long next_pfn;
>> +
>> + next_pfn = skip_offline_sections_reverse(block_start_pfn);
>> + if (next_pfn)
>> + block_start_pfn = max(pageblock_start_pfn(next_pfn),
>> + low_pfn);
>> +
>> continue;
>> + }
>>
>> /* Check the block is suitable for migration */
>> if (!suitable_migration_target(cc, page))
Powered by blists - more mailing lists