From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-202.mailbox.org (mout-p-202.mailbox.org [80.241.56.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E2211948E8; Wed, 13 Mar 2024 17:03:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710349394; cv=none; b=JhWsHHMYAexyubg7GxEVOHzufseHo5fxlllAWta3VgFUOfCO35J8f43dHHemXWV49NsSlrV6lSxR7wXsaJrnBcPBhvdgl7GRKrRF+rLZozZ0rJRfYm8zTivZK+fdqlI23HlyKRsjKSWkvE1oQlqQzZrcOS5EXV2y73/x0QtT3qA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710349394; c=relaxed/simple; bh=ZMppSe3CLJUbYtty6hKMUnmRewuVLsS/1omALJEd3z8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Q48zLmQOqJniXjAIMsuUzgeNdqnRVB7TBFbZr4b8EK42Pnhe9iu4i4jAcln32IwMo1+L65TFpseHFYj90wCcWCpUlb7mli0A4p6Y45SJdye0+h8RLIUDl9oZIlpJhbxKhY+D4EKfumHIqhIquXeMVUasgq33n8trrsg2TVEtcUM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pankajraghav.com; spf=pass smtp.mailfrom=pankajraghav.com; dkim=pass (2048-bit key) header.d=pankajraghav.com header.i=@pankajraghav.com header.b=ePofVGEs; arc=none smtp.client-ip=80.241.56.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=pankajraghav.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pankajraghav.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=pankajraghav.com header.i=@pankajraghav.com header.b="ePofVGEs" Received: from smtp102.mailbox.org (smtp102.mailbox.org [10.196.197.102]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 4TvxfF6kKKz9scJ; Wed, 13 Mar 2024 18:03:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pankajraghav.com; s=MBO0001; t=1710349381; 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=0O7jkYtxzM0DX7ZIGW+ZLQ370PUm3ZF/59ff/K84oK4=; b=ePofVGEsoAuYyqzVJOkLIjTDjgCqkUNNOdF5wzwok0juW1t96f6PLR+0tjm1jOKGs4hvX2 3677Dz+o7Boi66JMyxVV3+rcqBM/OQu7ZXWHFTDqbmsoC/7VAPHy8TXOPLcs2xNnWRdkls 5zLtrlq5B3Db6hJMkwoK7tF/b70+gbA+5G2XTJN6N/txcjTwGP+K/vtKUQExim+4ia4n7n ufxGGEgxOz5AjhMheKmu+XTB6CPt+uDyD+W2r3Efm4IK01gSenpsNoFRF73WLWeosdEIZA +kfkH2IJb5NGiYEd/YRBYCG5IsKjX7RavQEu4I7XeTAXcIo7nWlaRlfBUhvZ4A== From: "Pankaj Raghav (Samsung)" To: willy@infradead.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: gost.dev@samsung.com, chandan.babu@oracle.com, hare@suse.de, mcgrof@kernel.org, djwong@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, david@fromorbit.com, akpm@linux-foundation.org Subject: [PATCH v3 01/11] mm: Support order-1 folios in the page cache Date: Wed, 13 Mar 2024 18:02:43 +0100 Message-ID: <20240313170253.2324812-2-kernel@pankajraghav.com> In-Reply-To: <20240313170253.2324812-1-kernel@pankajraghav.com> References: <20240313170253.2324812-1-kernel@pankajraghav.com> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 4a30de98a8c7..a1cb3ea55fb6 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; -- 2.43.0