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[109.81.92.77]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-371898aabdesm3893021f8f.99.2024.08.16.08.57.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Aug 2024 08:57:35 -0700 (PDT) Date: Fri, 16 Aug 2024 17:57:34 +0200 From: Michal Hocko To: Christoph Hellwig Cc: Yafang Shao , Andrew Morton , viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, david@fromorbit.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Kent Overstreet Subject: Re: [PATCH] mm: document risk of PF_MEMALLOC_NORECLAIM Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 93FE4A0023 X-Stat-Signature: cwrmeyobwieut3jais9aieiftzedmyp4 X-Rspam-User: X-HE-Tag: 1723823857-934883 X-HE-Meta: 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 mQDVdjp4 RxyhwIBHUhXFj4lEjjPnoECe+GRhEUo/EiSeA8tolGhnGgBFIlRIaw97DACe/iKYYtr+oBGOtH9WfOxaSIpYydE5yaPWmZMKm/F7JVQK011GEGz4HgbBxiI//w7H1njhfMl0h+0hHpUiygUj872xE8FN/fg/hX2NTghcnhA7pvkBfth/RO2j19RRuMwl5oTFyO7aA9eS2qmk39XkK/6Gw3EAk8MQXItSlfWva2uWhg/5soeqmw2Ij+Z3qw23VPao9F+3L2SR2QVT5gp50XhDRefRXuNGVy8UrE1yLdQcbNbK5y9wzkrP1j4ZaltQkE232QUHainuI0kvISfMxBp5kq1VQSBeVaYvpxMXNZknwr/4MAztDwjyrR3u9J1DQJSr7BzwDe5Pi+QvVr341JSxYMdqIhg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000070, 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 Fri 16-08-24 07:26:06, Christoph Hellwig wrote: > On Fri, Aug 16, 2024 at 10:54:37AM +0200, Michal Hocko wrote: > > Yes, I think we should kill it before it spreads even more but I would > > not like to make the existing user just broken. I have zero visibility > > and understanding of the bcachefs code but from a quick look at __bch2_new_inode > > it shouldn't be really terribly hard to push GFP_NOWAIT flag there > > directly. It would require inode_init_always_gfp variant as well (to not > > touch all existing callers that do not have any locking requirements but > > I do not see any other nested allocations. > > I'll probably have to go down into security_inode_alloc as well. yes, I have done that as well. I was not sure about inode_alloc_security. It has alloc in the name but none of the caller actually allocate from there. lsm_inode_alloc was trivial to update. > That being said there is no explanation for the behavior here in the > commit logs or the code itself, so who knows. -- Michal Hocko SUSE Labs