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Mon, 08 Dec 2025 06:36:37 -0800 (PST) Received: from localhost ([185.92.221.13]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-647b4121f07sm11249779a12.28.2025.12.08.06.36.37 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 08 Dec 2025 06:36:37 -0800 (PST) From: Wei Yang To: akpm@linux-foundation.org, david@kernel.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, linmiaohe@huawei.com, nao.horiguchi@gmail.com Cc: linux-mm@kvack.org, Wei Yang Subject: [RFC Patch 07/11] mm/huge_memory: separate uniform/non uniform split logic in __split_unmapped_folio() Date: Mon, 8 Dec 2025 14:36:12 +0000 Message-Id: <20251208143616.20797-8-richard.weiyang@gmail.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20251208143616.20797-1-richard.weiyang@gmail.com> References: <20251208143616.20797-1-richard.weiyang@gmail.com> X-Rspamd-Queue-Id: BF1D01C0014 X-Stat-Signature: dg3j98t4twkt6si98muu1xzwqkbfj9zs X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1765204599-564345 X-HE-Meta: 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 V78myh3D e3gDNCCfExHzZ1H4kvU6a8ZYHIZDmWvpwYXu9Ajl9JRC3m9Fw6KtUl+EVlsaV5CIAPjQD9nTAhdm0/QA0z+/hYok22GOwioaYbrINLCkORsSVJKD0WkZu8LT8G/fY13/WwSs3tjEPBzQ4yiLhXksLv1rxykyiYyDjcNAcG7bzeeWfUcTuiHtp47C14H5liwKYVVqPfhlxooV3TT2ovzXBILdOw6xlKsMrshxIp5xLzpN8BKh+fLTAOTo24Ven4VS+Sf9W+aamkyDMk5sWP5yizSRt6NS1DDM3qljeGcpfSs1k+p+l5+s8tY7YnNFQlUlo7Cg7vzvL/1x15ssoL8uVsW3PqDZrO0vfGyNkPCG2y/ZKuyXm0aln0rxPSpCe4JbPHWKWzetNdQZhdRnGA0gPhxgOhLCB/2Rl3ODcckOsuZZTHSGzyDFTlJGfhrqOIw4o0XCoWxzyWGqkKCzJjDkhhnlOOzHPbPbm2OwawMhU4r8wgh4ANfvs0qK2v/bgICVDasP7Vwz8zZo1c65VVerU24ZwfaQg3EzGNW09txF9VqnTmKlY3SyNUiSfNUAu9cJ1InfIoQxBGKUEkBO9oZSftH1zho3RU9SbNTMxPpjvvoxU/4KuRWTg8wkINGp7t6etjP95MbV7oiV5bIE= 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: List-Subscribe: List-Unsubscribe: By utilizing the newly introduced __split_folio_and_update_stats() helper function, we can now clearly separate the logic for uniform and non-uniform folio splitting within __split_unmapped_folio(). This refactoring greatly simplifies the code by creating two distinct execution paths: * Uniform Split: Directly calls __split_folio_and_update_stats() once to achieve the @new_order in a single operation. * Non-Uniform Split: Continues to use a loop to iteratively split the folio to a single lower order at a time, eventually reaching the @new_order. This separation improves code clarity and maintainability. Signed-off-by: Wei Yang Cc: Lorenzo Stoakes Cc: Zi Yan Cc: "David Hildenbrand (Red Hat)" --- mm/huge_memory.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 7160254ce76c..dbb4b86e7d6d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3634,14 +3634,20 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, { const bool is_anon = folio_test_anon(folio); int old_order = folio_order(folio); - int start_order = split_type == SPLIT_TYPE_UNIFORM ? new_order : old_order - 1; int split_order; + /* For uniform split, folio is split to new_order directly. */ + if (split_type == SPLIT_TYPE_UNIFORM) { + if (mapping) + xas_split(xas, folio, old_order); + __split_folio_and_update_stats(folio, old_order, new_order); + return 0; + } + /* - * split to new_order one order at a time. For uniform split, - * folio is split to new_order directly. + * For non-uniform, split to new_order one order at a time. */ - for (split_order = start_order; + for (split_order = old_order - 1; split_order >= new_order; split_order--) { /* order-1 anonymous folio is not supported */ @@ -3654,21 +3660,16 @@ static int __split_unmapped_folio(struct folio *folio, int new_order, * irq is disabled to allocate enough memory, whereas * non-uniform split can handle ENOMEM. */ - if (split_type == SPLIT_TYPE_UNIFORM) - xas_split(xas, folio, old_order); - else { - xas_set_order(xas, folio->index, split_order); - xas_try_split(xas, folio, old_order); - if (xas_error(xas)) - return xas_error(xas); - } + xas_set_order(xas, folio->index, split_order); + xas_try_split(xas, folio, old_order); + if (xas_error(xas)) + return xas_error(xas); } __split_folio_and_update_stats(folio, old_order, split_order); /* - * If uniform split, the process is complete. - * If non-uniform, continue splitting the folio at @split_at - * as long as the next @split_order is >= @new_order. + * Continue splitting the folio at @split_at as long as the + * next @split_order is >= @new_order. */ folio = page_folio(split_at); old_order = split_order; -- 2.34.1