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Mon, 26 Feb 2024 10:49:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1708940986; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O82T73AIK6qGhlYorGzOupTzei7wEk6+FPA8o3URJUE=; b=fFQkG18oqQYxyzAvUU/y6Xu/XNWxZbMy3Hto7NjxLMdpH4n7PnYGdCLyHr4oXKUWbXSdbt 3kIMgsOe+HNJi2CzUuOzIN8/o3Hwj48BF9JSpk1ELMgKLrxDpkLn7dQHexpKbAy6k3on3h tAY9LeXQaVX3Z0icnnr5KaXGnxzwdyT+lKKy4CYh251ECjLnS+cXrDxGEVm36OGNJwQwRd 47PB4v+rzOClutu21cDUGzMEc1J6st9TU1ML2CZo9yDdBjMu2qdfyN76b5tzCIv54RiQR8 MMZn9aLw+WeROCUn9RtgqMYpFq+RNdlieT4wk3ZhHKWPj+rdmiFDG5WMdnHFZg== From: "Pankaj Raghav (Samsung)" To: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org, david@fromorbit.com, chandan.babu@oracle.com, akpm@linux-foundation.org, mcgrof@kernel.org, ziy@nvidia.com, hare@suse.de, djwong@kernel.org, gost.dev@samsung.com, linux-mm@kvack.org, willy@infradead.org Subject: [PATCH 01/13] mm: Support order-1 folios in the page cache Date: Mon, 26 Feb 2024 10:49:24 +0100 Message-ID: <20240226094936.2677493-2-kernel@pankajraghav.com> In-Reply-To: <20240226094936.2677493-1-kernel@pankajraghav.com> References: <20240226094936.2677493-1-kernel@pankajraghav.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: B02B620005 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: deqgfj19bn87euc4gwow8k73d899jn6n X-HE-Tag: 1708940990-927624 X-HE-Meta: U2FsdGVkX18kpS1ghjqie/aFfJdaBaiAtYsLJ8qd/fhH+lVEiPve/eY2CxqlOlQqrGqL8aJOEDu6CkKDAZPpLV8aLz/h6vKcmhxA+JdorNJjYedHMc+EPhEKzDFW25/tqpDyH83nEyUn8fO0JMzqSbyIPW7wHR+UdsfjsyZNnk6Qu9D0tFbFRtbcF4pSgoJlnYO1p4ZGlBS4UhVEZO9kBFNPEJk/3bwpEHTSh53Un1I6+OVF353iqF8hd6+9SBnG/eyEFVMkrr1GlcuUU7d/kH4rIAn5HXtZAa0KxPhKbS/Qr0pJ4CMrPRtfOJykprl8tz3pxgVe6M5tMiWKdlMsGMl6qSqNBc4rQwYHjdp/YYqCqZJ/uuxhU9b3UArGkvHKco2qU+fJbnu6iUsxLxh30dNWkn4JoxjZD7eIb1Lmeelj58GcWiLS+m7fyOAeijp5PsxNLdLrOsVU4DSwsLmy+4WR4knsU/skHTb96VNTUeizEdrg+5Ye7frFi9kqhsbWMkscsj/6IoeEah/fg/FPictRgixdvj3FjIActNyuchsOQeLAXIZ310kjRGlNza+8QOUlEy2EhdWiScsXuIT309XXelTzKoGhnA/B7Z+fJQQ3jImF4G5eqiiciy2Fpi+7ioRaa58zP95IbOfT+CtN+aMCfbhxJyWEChQfBRXj78qZSPeAfSbdbskvdXYaaxqPby9h0TWzGu8cGbVtul15rA3B2zC4lHHaLQqStlGw+mYlxA6XGFaVGPU82O1cbMWWe4BLRd1HKaJeB3nmuN7NUAjVjT4Qv6tUlG6LqXH+/wP9p8kD0LPHAM7p9aqFbHMsofoOZ1vNeMeCkCRzqs2oEwtOXoQSqCr3QWxt3AH8NTiSpy1GfF/RyqXMb82VxjAgtR13gqBEqWnbqNsJ5wc8IhWSk1fiBnRKkSvuA7jVckOboorl4YSfwqwWWv5l9EZaH3elSG1Obfch+p+qWBL czdPQnmS VaA05/V5nH4tvp1PMSxWvez2GghhoVTQ+O+ZYjT2JQPMNKTpYQX65aEll7buhinnhLqv1 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: From: "Matthew Wilcox (Oracle)" Folios of order 1 have no space to store the deferred list. This is not a problem for the page cache as file-backed folios are never placed on the deferred list. All we need to do is prevent the core MM from touching the deferred list for order 1 folios and remove the code which prevented us from allocating order 1 folios. Link: https://lore.kernel.org/linux-mm/90344ea7-4eec-47ee-5996-0c22f42d6a6a@google.com/ Signed-off-by: Matthew Wilcox (Oracle) --- include/linux/huge_mm.h | 7 +++++-- mm/filemap.c | 2 -- mm/huge_memory.c | 23 ++++++++++++++++++----- mm/internal.h | 4 +--- mm/readahead.c | 3 --- 5 files changed, 24 insertions(+), 15 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 5adb86af35fc..916a2a539517 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -263,7 +263,7 @@ unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma, unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags); -void folio_prep_large_rmappable(struct folio *folio); +struct folio *folio_prep_large_rmappable(struct folio *folio); bool can_split_folio(struct folio *folio, int *pextra_pins); int split_huge_page_to_list(struct page *page, struct list_head *list); static inline int split_huge_page(struct page *page) @@ -410,7 +410,10 @@ static inline unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma, return 0; } -static inline void folio_prep_large_rmappable(struct folio *folio) {} +static inline struct folio *folio_prep_large_rmappable(struct folio *folio) +{ + return folio; +} #define transparent_hugepage_flags 0UL diff --git a/mm/filemap.c b/mm/filemap.c index 750e779c23db..2b00442b9d19 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1912,8 +1912,6 @@ struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, gfp_t alloc_gfp = gfp; err = -ENOMEM; - if (order == 1) - order = 0; if (order > 0) alloc_gfp |= __GFP_NORETRY | __GFP_NOWARN; folio = filemap_alloc_folio(alloc_gfp, order); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 94c958f7ebb5..81fd1ba57088 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -788,11 +788,15 @@ struct deferred_split *get_deferred_split_queue(struct folio *folio) } #endif -void folio_prep_large_rmappable(struct folio *folio) +struct folio *folio_prep_large_rmappable(struct folio *folio) { - VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); - INIT_LIST_HEAD(&folio->_deferred_list); + if (!folio || !folio_test_large(folio)) + return folio; + if (folio_order(folio) > 1) + INIT_LIST_HEAD(&folio->_deferred_list); folio_set_large_rmappable(folio); + + return folio; } static inline bool is_transparent_hugepage(struct folio *folio) @@ -3082,7 +3086,8 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) /* Prevent deferred_split_scan() touching ->_refcount */ spin_lock(&ds_queue->split_queue_lock); if (folio_ref_freeze(folio, 1 + extra_pins)) { - if (!list_empty(&folio->_deferred_list)) { + if (folio_order(folio) > 1 && + !list_empty(&folio->_deferred_list)) { ds_queue->split_queue_len--; list_del(&folio->_deferred_list); } @@ -3133,6 +3138,9 @@ void folio_undo_large_rmappable(struct folio *folio) struct deferred_split *ds_queue; unsigned long flags; + if (folio_order(folio) <= 1) + return; + /* * At this point, there is no one trying to add the folio to * deferred_list. If folio is not in deferred_list, it's safe @@ -3158,7 +3166,12 @@ void deferred_split_folio(struct folio *folio) #endif unsigned long flags; - VM_BUG_ON_FOLIO(folio_order(folio) < 2, folio); + /* + * Order 1 folios have no space for a deferred list, but we also + * won't waste much memory by not adding them to the deferred list. + */ + if (folio_order(folio) <= 1) + return; /* * The try_to_unmap() in page reclaim path might reach here too, diff --git a/mm/internal.h b/mm/internal.h index f309a010d50f..5174b5b0c344 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -419,9 +419,7 @@ static inline struct folio *page_rmappable_folio(struct page *page) { struct folio *folio = (struct folio *)page; - if (folio && folio_order(folio) > 1) - folio_prep_large_rmappable(folio); - return folio; + return folio_prep_large_rmappable(folio); } static inline void prep_compound_head(struct page *page, unsigned int order) diff --git a/mm/readahead.c b/mm/readahead.c index 2648ec4f0494..369c70e2be42 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -516,9 +516,6 @@ void page_cache_ra_order(struct readahead_control *ractl, /* Don't allocate pages past EOF */ while (index + (1UL << order) - 1 > limit) order--; - /* THP machinery does not support order-1 */ - if (order == 1) - order = 0; err = ra_alloc_folio(ractl, index, mark, order, gfp); if (err) break;