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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pfa1s-004bzx-0b; Fri, 24 Mar 2023 05:31:56 +0000 Date: Fri, 24 Mar 2023 05:31:55 +0000 From: Matthew Wilcox To: Dave Chinner Cc: Uladzislau Rezki , Lorenzo Stoakes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton , Baoquan He , David Hildenbrand , Liu Shixin , Jiri Olsa Subject: Re: [PATCH v2 2/4] mm: vmalloc: use rwsem, mutex for vmap_area_lock and vmap_block->lock Message-ID: References: <6c7f1ac0aeb55faaa46a09108d3999e4595870d9.1679209395.git.lstoakes@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: tugcwr7o8g5c9q6xmwqh341oq8w898qy X-Rspamd-Queue-Id: 07F228000B X-HE-Tag: 1679635921-424180 X-HE-Meta: U2FsdGVkX1+OBo/gqzTWSKGHGyJLLzUhuJC5LNdE2Yx6ahCSBOtrjTliCbaIDn62mUUXKbF3aYLMUaCTMGpBj4hU9kN9HOsVxfA8ZwguRfR9H5WLD7CBfXqkqXh69bxyvGZVj3CMmuKl2sRD+VAv68In8U81PgmIHcSukAEFqw/8hkaZDiOJZ3BMYmI4UQmV10vWT21kTXYqrjzBpuviyv3ppkUthE3HznwenylUcg6bfZLnGL3aHG5aLiiMoCoaZKU4aPosPSCCJ6Kgbeh49QuiGHqOPpb25TNG6Ni8sQHACMeBKHjv8bICSmidyLjcTQpQ5RYTDH/B1n5iExmp30FMSe8y7mRW9vaVDpmKXfqmrG1EFYFlJsannKsYfoUPlv0a3NB9o+sOMLrIChFhHjgqmO4oP+M8GdBhhhHUp8v+FdLsH/fIg2lFEz9PE+EGbg35pjqBAu8XUJ7no5YMT6F1JGY069kM/z2JbceKwgr2Bfw38SOoEnEhXPHVC7D/iDsZegx21/XuXK6/dATvUSlmjnUNBHOiKPFPIN0+3qkVa4WULcFnUZqQzOnCEQTSzLFe3o/YXlfHCQkV3oq5twIxIYHdMfJBrnmioZ8eGfXDaZwkNPOpphYsvX7AgMMUwOST+X2xORcs9XQ1Naz4sy3iknZWkcqI1C00J2WtEjvLOyxUzxuFWeYf7Wvlau5kFwE5dXY5zxXAydNu7Hsah+EgeCZ08iIIMTLjWi53JVnklnENLyLRwuU0ubVxyMElxmKM+InXr9w19oq51hNjbXUTfSwzYpmBnGP/5kTskEMqDPpXhxxdJj192EzK1dVTerIPPB+TcjJBGHZv2NLZ04V6o44jVwn686nLyqHT4gcSgaXuHTGinVea7rtisUGTRphzYKXt5FgNxYli0wwhp3x9KwS+CN0TeT1nqmoeGAtYaYRtIBfhksAnqsgVsdBD+jp1/5m4aB6GiQqXGQX jaSE+hLw +kFbJ/Ty5sS76pMlLPHM9uEOEPO54vSTtTpDz2EoPSfuWZniopOM1DXDksvlNRPetSAqvaq5ve7vpNQn3euPPIQdKjI3a03Wm7BuJ+YgOKc8Z7fWo1oYvbwOK5MXONOS5tsU0eFq7AYoitLaR0BRHS+mvzG+mXIcyXUOqjny+VJ4ewOMISXDGVnAcOqUSWTcJKoiAF8CthFMG/no= 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: On Fri, Mar 24, 2023 at 04:25:39PM +1100, Dave Chinner wrote: > Did you read the comment above this function? I mean, it's all about > how poorly kvmalloc() works for the highly concurrent, fail-fast > context that occurs in the journal commit fast path, and how we open > code it with kmalloc and vmalloc to work "ok" in this path. > > Then if you go look at the commits related to it, you might find > that XFS developers tend to write properly useful changelogs to > document things like "it's better, but vmalloc will soon have lock > contention problems if we hit it any harder".... The problem with writing whinges like this is that mm developers don't read XFS changelogs. I certainly had no idea this was a problem, and I doubt anybody else who could make a start at fixing this problem had any idea either. Why go to all this effort instead of sending an email to linux-mm?