From nobody Sun Dec 14 21:14:29 2025 Received: from mail-io1-f44.google.com (mail-io1-f44.google.com [209.85.166.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D57F721CA1C for ; Fri, 20 Dec 2024 15:48:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734709733; cv=none; b=gwJIwFJHPpyrO1rpYPiYOEq7hR6pUJsocTY7pQp1XlMkGraOnY8zwEJV6RcYCgnjpJHlMBSav4JANjaPAVst8qU6/AnYcL33YlR9tghvmxxMxmZavyjnkcESoNTaSUWF0ihfqfg0KgEzjyo2Uq+1jlbfb1xQ3XVYLbJQKtJ6f7I= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734709733; c=relaxed/simple; bh=nMl1WIMQHt2bPQz6aG6MCeSjhSpxjtnQ2LzuXFwS3EE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FBgqOj7GID5cfWzYMwKs3spJ8MJIFWA9/j1fg8aGTOfs2N7wHW7smSZAe2fjfMGwxzgybewh6jYq3s7tjTORCQzqMETqf8DB5JkIflrDg54xhoim1YajYBctce5pGmocQ7fEeusu8t+18/J0437a4rcGUDQ+70CYKTp8ojtuJYE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=rQoXGEdg; arc=none smtp.client-ip=209.85.166.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="rQoXGEdg" Received: by mail-io1-f44.google.com with SMTP id ca18e2360f4ac-844de072603so177572739f.0 for ; Fri, 20 Dec 2024 07:48:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1734709731; x=1735314531; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=86GdD84SMshyNZnB2LgwxYI5vb/3z8g/QfHnuRLr9vU=; b=rQoXGEdgBAzash2UkPI/h6AWqTly2sPjVW9b7hA4HKvUEDfPRY9hME8xK+5OHk9dPB imdsvJiZzoYLSP1vgailaI0VzLusxo0vLieDcqeeQsKtokxL9Y8ZP3QaILODAfuWpe8R 1StjFxmLHfw26Thl9noyWzN8NYsirgyQkUFyhe2nQAs4waoVe01LDIQsJOzfrAd1+4b4 reZMrtNARzwTYhjFHd+s3dWJ7Wjg9zBWH1SZ//2Lk3JMTczFKAFrBRdlDnf8vYolCv7N kynphxojBktG2JkHYrhoDacuNHMOPY9LODRFxN4kdxcuG4IeO6nP5L9fpm6gAs/Jm4sz 3vZA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734709731; x=1735314531; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=86GdD84SMshyNZnB2LgwxYI5vb/3z8g/QfHnuRLr9vU=; b=cEBtdXSh4kePOa+DkAVYTnyg/Id/B2tEz3ua05/QVY1Tsbg0flj44WNf3/ll7403Mw Q91Xe8RS232NfLuQtabsSLBJfljAr9oaMDIw1teYLIg5b4XUmq0Yw1ubWc4ifY+R4wFv od8L+l3dynZkqlx7V6mejFX2civqOYId73ivbemoBqxgWQNwGM0xE8+AcMokA+AMkEIi AaPgU7suu4bZh9yn320TreDeTr9E9YhDgePLpdLxnsh0FxkdaJJosx8FEVcxf3TT2X0B PzbA1kr6B+DI9e3Su2BuOCZJt2tVKPMFo5MtAe14r5CbqacRC1uX5jjDxtaoXu1rxsAM OooA== X-Forwarded-Encrypted: i=1; AJvYcCVNCRYSDwStbARFrRMfyphl4sGffhrNr1LxYQ3JGwQpwD7MkN3rbibMn8nVhP0jXwXCou/w06Nd0bSRPXY=@vger.kernel.org X-Gm-Message-State: AOJu0YwxBnFdCc46Eibyhtfd/NwvW80USV0borkV0qcGN7pPEISeIKNz yWS0pqR0M6RMqJLd8kwXFXl8epqsumrSwqkr11Rivgl23sXDU38/So1aU4BsiUI= X-Gm-Gg: ASbGnct5j77TW53SyrptYZVx0txPqpTY9MNvyILw1swZcHq8mJbRsX3+bbthrBeacQ8 AJBImDLuKgC0RPv0ipbOw3Foh4OUGq9h6gvaJiXOtfNUiUPwTULQFlROo5nOf9xrSIgUUhSefUA YOepzfnxhK073FxpZ+5rYeLMy5WoC7WK9RPOwGUFPpuLM8YRV4ZRi0bTwWpYha6a3Ga0oMr8YVO qxrYDRjAF9sAJaRfp4y+Q1piKkBwIDX6fPyln0rWHTRqKRxp5uy4/Gpexs1 X-Google-Smtp-Source: AGHT+IENwEpB78XkZV/FFvO7zp/8wAKDMGCn+bUr8XfGQ9+IvUs//gy2KTAuIDXDGGYGOcgB+kegLA== X-Received: by 2002:a05:6e02:20c1:b0:3a7:e3e3:bd57 with SMTP id e9e14a558f8ab-3c2d533e943mr33235325ab.15.1734709731154; Fri, 20 Dec 2024 07:48:51 -0800 (PST) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id 8926c6da1cb9f-4e68bf66ed9sm837821173.45.2024.12.20.07.48.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Dec 2024 07:48:50 -0800 (PST) From: Jens Axboe To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Cc: hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org, willy@infradead.org, kirill@shutemov.name, bfoster@redhat.com, Jens Axboe Subject: [PATCH 12/12] mm: add FGP_DONTCACHE folio creation flag Date: Fri, 20 Dec 2024 08:47:50 -0700 Message-ID: <20241220154831.1086649-13-axboe@kernel.dk> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241220154831.1086649-1-axboe@kernel.dk> References: <20241220154831.1086649-1-axboe@kernel.dk> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Callers can pass this in for uncached folio creation, in which case if a folio is newly created it gets marked as uncached. If a folio exists for this index and lookup succeeds, then it will not get marked as uncached. If an !uncached lookup finds a cached folio, clear the flag. For that case, there are competeting uncached and cached users of the folio, and it should not get pruned. Signed-off-by: Jens Axboe --- include/linux/pagemap.h | 2 ++ mm/filemap.c | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 5da4b6d42fae..64c6dada837e 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -710,6 +710,7 @@ pgoff_t page_cache_prev_miss(struct address_space *mapp= ing, * * %FGP_NOFS - __GFP_FS will get cleared in gfp. * * %FGP_NOWAIT - Don't block on the folio lock. * * %FGP_STABLE - Wait for the folio to be stable (finished writeback) + * * %FGP_DONTCACHE - Uncached buffered IO * * %FGP_WRITEBEGIN - The flags to use in a filesystem write_begin() * implementation. */ @@ -723,6 +724,7 @@ typedef unsigned int __bitwise fgf_t; #define FGP_NOWAIT ((__force fgf_t)0x00000020) #define FGP_FOR_MMAP ((__force fgf_t)0x00000040) #define FGP_STABLE ((__force fgf_t)0x00000080) +#define FGP_DONTCACHE ((__force fgf_t)0x00000100) #define FGF_GET_ORDER(fgf) (((__force unsigned)fgf) >> 26) /* top 6 bits */ =20 #define FGP_WRITEBEGIN (FGP_LOCK | FGP_WRITE | FGP_CREAT | FGP_STABLE) diff --git a/mm/filemap.c b/mm/filemap.c index 9842258ba343..68bdfff4117e 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2001,6 +2001,8 @@ struct folio *__filemap_get_folio(struct address_spac= e *mapping, pgoff_t index, /* Init accessed so avoid atomic mark_page_accessed later */ if (fgp_flags & FGP_ACCESSED) __folio_set_referenced(folio); + if (fgp_flags & FGP_DONTCACHE) + __folio_set_dropbehind(folio); =20 err =3D filemap_add_folio(mapping, folio, index, gfp); if (!err) @@ -2023,6 +2025,9 @@ struct folio *__filemap_get_folio(struct address_spac= e *mapping, pgoff_t index, =20 if (!folio) return ERR_PTR(-ENOENT); + /* not an uncached lookup, clear uncached if set */ + if (folio_test_dropbehind(folio) && !(fgp_flags & FGP_DONTCACHE)) + folio_clear_dropbehind(folio); return folio; } EXPORT_SYMBOL(__filemap_get_folio); --=20 2.45.2