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Received: from willy by casper.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1rmPiz-00000000zr6-0G1V; Tue, 19 Mar 2024 03:01:13 +0000 Date: Tue, 19 Mar 2024 03:01:12 +0000 From: Matthew Wilcox To: Zhaoyang Huang Cc: =?utf-8?B?6buE5pyd6ZizIChaaGFveWFuZyBIdWFuZyk=?= , Andrew Morton , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , =?utf-8?B?5bq357qq5ruoIChTdGV2ZSBLYW5nKQ==?= Subject: Re: summarize all information again at bottom//reply: reply: [PATCH] mm: fix a race scenario in folio_isolate_lru Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: osq7mbm7mf7suajne51uskdhkus48ta5 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 700C88000C X-Rspam-User: X-HE-Tag: 1710817285-915528 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000178, 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 Tue, Mar 19, 2024 at 08:48:42AM +0800, Zhaoyang Huang wrote: > BTW, damon_pa_pageout is a potential risk over this race No it isn't. struct folio *folio = damon_get_folio(PHYS_PFN(addr)); if (!folio) continue; if (damos_pa_filter_out(s, folio)) goto put_folio; folio_clear_referenced(folio); folio_test_clear_young(folio); if (!folio_isolate_lru(folio)) goto put_folio; if (folio_test_unevictable(folio)) folio_putback_lru(folio); else list_add(&folio->lru, &folio_list); put_folio: folio_put(folio); It clearly has a folio reference when it calls folio_isolate_lru().