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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v1 06/10] mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS Message-ID: References: <20260327014255.2058916-1-ziy@nvidia.com> <20260327014255.2058916-7-ziy@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260327014255.2058916-7-ziy@nvidia.com> X-Stat-Signature: emoxh19ggysn3aemyp6f9eqb9t1mder3 X-Rspamd-Queue-Id: B49AAA0010 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774615836-470601 X-HE-Meta: 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 wMgdXPwG 3E6F1B8vAcXgWKvueYtNsqfrrzQoEhNQh/6VI0D3rQLaiPbU1bPNoytUGBEmeWP1HajP/47U3nFFKocHOcaO32quWFPj/ffcaBZ8p7SgyRBbQcsuyNoir769EUuX4BvQlVG+4GbaK4798Y1tL6xhvYK8CNpCXSFxpQcwd6/d9My52adFEXto/U+CL0J4M/qUOc6RPiGsjj1BVZoBq62HzQRndCBD84EXxtTYkLevXzOZlrl37l3TEtBMr9QU08zpC17ZEB1gVyVqFLj2iS8IL9hKKKnX1T6zpMW4HWfqnb+St/ubL7OLpTh68PQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 26, 2026 at 09:42:51PM -0400, Zi Yan wrote: > Without READ_ONLY_THP_FOR_FS, large file-backed folios cannot be created by > a FS without large folio support. The check is no longer needed. > > Signed-off-by: Zi Yan Seems legitimate, so: Reviewed-by: Lorenzo Stoakes (Oracle) > --- > mm/huge_memory.c | 22 ---------------------- > 1 file changed, 22 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 1da1467328a3..30eddcbf86f1 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3732,28 +3732,6 @@ int folio_check_splittable(struct folio *folio, unsigned int new_order, > /* order-1 is not supported for anonymous THP. */ > if (new_order == 1) > return -EINVAL; > - } else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) { > - if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && > - !mapping_large_folio_support(folio->mapping)) { > - /* > - * We can always split a folio down to a single page > - * (new_order == 0) uniformly. > - * > - * For any other scenario > - * a) uniform split targeting a large folio > - * (new_order > 0) > - * b) any non-uniform split > - * we must confirm that the file system supports large > - * folios. > - * > - * Note that we might still have THPs in such > - * mappings, which is created from khugepaged when > - * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that > - * case, the mapping does not actually support large > - * folios properly. > - */ > - return -EINVAL; > - } > } > > /* > -- > 2.43.0 >