From: Vlastimil Babka <vbabka@suse.cz>
To: "chenjun (AM)" <chenjun102@huawei.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"cl@linux.com" <cl@linux.com>,
"penberg@kernel.org" <penberg@kernel.org>,
"rientjes@google.com" <rientjes@google.com>,
"iamjoonsoo.kim@lge.com" <iamjoonsoo.kim@lge.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: "xuqiang (M)" <xuqiang36@huawei.com>,
"Wangkefeng (OS Kernel Lab)" <wangkefeng.wang@huawei.com>
Subject: Re: [PATCH] mm/slub: Reduce memory consumption in extreme scenarios
Date: Fri, 17 Mar 2023 13:06:04 +0100 [thread overview]
Message-ID: <8c700468-245d-72e9-99e7-b99d4547e6d8@suse.cz> (raw)
In-Reply-To: <344c7521d72e4107b451c19b329e9864@huawei.com>
On 3/17/23 12:32, chenjun (AM) wrote:
> 在 2023/3/14 22:41, Vlastimil Babka 写道:
>>> pc.flags = gfpflags;
>>> +
>>> + /*
>>> + * when (node != NUMA_NO_NODE) && (gfpflags & __GFP_THISNODE)
>>> + * 1) try to get a partial slab from target node with __GFP_THISNODE.
>>> + * 2) if 1) failed, try to allocate a new slab from target node with
>>> + * __GFP_THISNODE.
>>> + * 3) if 2) failed, retry 1) and 2) without __GFP_THISNODE constraint.
>>> + */
>>> + if (node != NUMA_NO_NODE && !(gfpflags & __GFP_THISNODE) && try_thisnode)
>>> + pc.flags |= __GFP_THISNODE;
>>
>> Hmm I'm thinking we should also perhaps remove direct reclaim possibilities
>> from the attempt 2). In your qemu test it should make no difference, as it
>> fills everything with kernel memory that is not reclaimable. But in practice
>> the target node might be filled with user memory, and I think it's better to
>> quickly allocate on a different node than spend time in direct reclaim. So
>> the following should work I think?
>>
>> pc.flags = GFP_NOWAIT | __GFP_NOWARN |__GFP_THISNODE
>>
>
> Hmm, Should it be that:
>
> pc.flags |= GFP_NOWAIT | __GFP_NOWARN |__GFP_THISNODE
No, we need to ignore the other reclaim-related flags that the caller
passed, or it wouldn't work as intended.
The danger is that we ignore some flag that would be necessary to pass, but
I don't think there's any?
next prev parent reply other threads:[~2023-03-17 12:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-14 12:34 [PATCH] mm/slub: Reduce memory consumption in extreme scenarios Chen Jun
2023-03-14 14:41 ` Vlastimil Babka
2023-03-17 11:32 ` chenjun (AM)
2023-03-17 12:06 ` Vlastimil Babka [this message]
2023-03-19 7:22 ` chenjun (AM)
2023-03-20 8:05 ` Vlastimil Babka
2023-03-20 9:12 ` Mike Rapoport
2023-03-21 9:30 ` chenjun (AM)
2023-03-29 8:41 ` Vlastimil Babka
2023-03-21 9:41 ` Vlastimil Babka
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