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Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vx6P9-00000009mbi-1QvE; Mon, 02 Mar 2026 16:45:59 +0000 Date: Mon, 2 Mar 2026 16:45:59 +0000 From: Matthew Wilcox To: WANG Rui Cc: Alexander Viro , Christian Brauner , Jan Kara , Kees Cook , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] binfmt_elf: Align eligible read-only PT_LOAD segments to PMD_SIZE for THP Message-ID: References: <20260302155046.286650-1-r@hev.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260302155046.286650-1-r@hev.cc> X-Rspamd-Queue-Id: 62E1D80015 X-Stat-Signature: 7fayee5apakem6cx3qiyremzspehs6b7 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1772469963-828789 X-HE-Meta: U2FsdGVkX1+EM7G18WwlXs1VNnIMRK5+Km/zu43OribWd/ER9zVvFIJlF3iQDugPXqWBlOD95fiUtDQggLTqMUfUjWyrxfINHOV7YrHyzA6HHPBQVok/E2mlIG6pPlVhoQRViB8LAdNYtJhLVjMHpifroj1B+6UOjXYFVlFUYDmJ/MS7+I2wh5dk7OQ1lzIIx3CiSYWUgapuMblz5Y66fMawTYaqRBgDjHYJQzdLW+y9YWoUsPFZ7DGNCs26hPW6HcSZMN+mHY3QgzFe2wxHmv21CFrA86B+9oTIqK30bw/SbIIrz1TY7hALK4+3EMquD3kCeIKalWQc084JJtrLxt7wsI3lxRJoPk8gnD60JEBx7SrbgvSeCdY1u7/jWjeQmOfNtEwkbd2KvlBx8TrGUaOetsQf+lLjhsC4JkvagsyF5tFsscxatc3eIbjfjodEkgUCbC+bBbnadEcdpYlljGTYzFSR2cXKSuCF+QvGDHkKmWB8ewd6Zhtwu0iIFh7ayck7b7sPW/rlkLwl317J8TXq1g/p04jpI0iqu/7y3kWh4FUniEOtMAvHwVU++QZlPUB3zGt+8vUZSYp3vnvK+Cv41B6Zmj1LBKLFa9bb6uHy8epuOFUE5p103JBiHJpEPb6GSdq2pBDC/gVtKV/Zh8zy4Vo1z0EuitPWv3Qf4K29fvXsHZpoZ8Mm7S4bTTsiwx15XzUDNhTRvcxxGIvcNDCoS9Bogr+4SkcbyS9BzP8tFbuUQda1KuhcOH887dCrhxRfmKHF9sB5dsd1YE/x48174+X9WaNR+m2+4BLGVZlynFieI7lA5WsTDdwkTVs3cr2+iQEDxAw0nUqpE+R2p//36PF/mGP4xKf2Se/wQqL+WAicAS61u1wWpZT4e51gi/FL71bTY1EO7ljqZjR9KLzGL0EuknvbmfEwnzyS4UKHkvPSvssSQeBZO5bv4NzauzQ1bva10baxdogmtXA uME8O6M3 Q6kvi0YHR4pKeDf1LP0s/iuGlQANZKIP4DRrfQt8ol7KXQ1pbQ0/fmlSpvLAlaIQWwxetBQem6rRjXdadcUWHNpq1pAhlCk4eTUb3R9gd2JBvgzpPze2xstH1r7TpiqAGoJDY8BS1A6BKM8wW3Qt5Vzrf29l86xD9sshg95sgM6JI8miJuVcFEr1BqI9EkOzw3zht1pbIZo3nHeOxkrW2ssU0CqqvkWf62PS8qzjsqJ38Ft4xesFHfSg5CsDsWsKVcxWDuSbRfBk51dOnzvCuZft43Q6d38X7O6/9SIvHIMtRIqE= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 02, 2026 at 11:50:46PM +0800, WANG Rui wrote: > +config ELF_RO_LOAD_THP_ALIGNMENT > + bool "Align read-only ELF load segments for THP (EXPERIMENTAL)" > + depends on READ_ONLY_THP_FOR_FS This doesn't deserve a config option. > +#if defined(CONFIG_ELF_RO_LOAD_THP_ALIGNMENT) && PMD_SIZE <= SZ_32M Why 32MB? This is weird and not justified anywhere. > + if (hugepage_global_always() && !(cmds[i].p_flags & PF_W) > + && IS_ALIGNED(cmds[i].p_vaddr | cmds[i].p_offset, PMD_SIZE) > + && cmds[i].p_filesz >= PMD_SIZE && p_align < PMD_SIZE) > + p_align = PMD_SIZE; Normal style is to put the '&&' at the end of the line: if (!(cmds[i].p_flags & PF_W) && IS_ALIGNED(cmds[i].p_vaddr | cmds[i].p_offset, PMD_SIZE) && cmds[i].p_filesz >= PMD_SIZE && p_align < PMD_SIZE)) p_align = PMD_SIZE; But this conditional is too complex to be at this level of indentation. Factor it out into a helper: if (align_to_pmd(cmds) && p_align < PMD_SIZE) p_align = PMD_SIZE;