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b=RwuL3ESEYW197t6wLrPEYOCN0yzspp1ChYPbd2CaJLzlk4/f+XdG1WmCEKTnMQ2Dm C57mwtqELyeCsf3EwCS1lt07rtE6ndT8KjcREe2+jUhQXV56ZG4N8EuLXrX/eOFjQs GDP+bYOum01YF7vOqiqf/tAFV7YR93oa1r0xe6kQ= Date: Tue, 2 Jul 2024 00:19:40 -0700 From: Andrew Morton To: Miaohe Lin Cc: Rui Qi , , , Subject: Re: [PATCH] mm/memory-failure: allow memory allocation from emergency reserves Message-Id: <20240702001940.43a9447a76b51a871d8dec97@linux-foundation.org> In-Reply-To: References: <20240625022342.6158-1-qirui.001@bytedance.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 7627520003 X-Stat-Signature: 35p511hsj3m7bshpanjehy7yn748qhk6 X-Rspam-User: X-HE-Tag: 1719904782-534375 X-HE-Meta: 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 WgFuzZHj Njzmci9VOnvN7PuSgyGfs5any096NmNMJG8/Z3+9+Y+r84xaMQB+EzUYeNoizijdKeP1ApwrX88LfrrHv0FKtdGi6i6Fq0qRjIDvn3wuewufrX1MUhBubjRHSQWQ0oRN4wOU32LoDWwBlkfB3ZkU4HLAuSIRUy1jREmYqDspzsy2M4oPLS5ooNzVtYNH/80PBbPmNZUmU4COsmxtT11zn77WEGf6mduwR8cB0KW+ws7fxrycDjA2VLbqbKucv4cuUve/UVQOZtxMexkf+kg4Odjmu/BU8xtyKU5RAo9lQveDVef6XXbftI/xSav8/7bjDWQufVXehx8AtnQjD/CrELt6viGdBxzDxmG7Rd8PYYk2Kli06SmBcvb6h7A== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, 29 Jun 2024 10:09:46 +0800 Miaohe Lin wrote: > On 2024/6/25 10:23, Rui Qi wrote: > > From: Rui Qi > > > > we hope that memory errors can be successfully handled quickly, using > > __GFP_MEMALLOC can help us improve the success rate of processing > > Comments of __GFP_MEMALLOC says: > > * Users of this flag have to be extremely careful to not deplete the reserve > * completely and implement a throttling mechanism which controls the > * consumption of the reserve based on the amount of freed memory. > > It seems there's no such throttling mechanism in memory_failure. > > > under memory pressure, because to_kill struct is freed very quickly, > > so using __GFP_MEMALLOC will not exacerbate memory pressure for a long time, > > and more memory will be freed after killed task exiting, which will also > > Tasks might not be killed even to_kill struct is allocated. > > ... > > > - raw_hwp = kmalloc(sizeof(struct raw_hwp_page), GFP_ATOMIC); > > + raw_hwp = kmalloc(sizeof(struct raw_hwp_page), GFP_ATOMIC | __GFP_MEMALLOC); > > In already hardware poisoned code path, raw_hwp can be allocated to store raw page info > without killing anything. So __GFP_MEMALLOC might not be suitable to use. > Or am I miss something? Yes, I'm doubtful about this patch. I think that rather than poking at a particular implementation, it would be helpful for us to see a complete description of the issues which were observed, please. Let's see the bug report and we can discuss fixes later.