From patchwork Mon Aug 26 08:47:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 13777444 Received: from mail-ed1-f54.google.com (mail-ed1-f54.google.com [209.85.208.54]) (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 C3ED282D7F; Mon, 26 Aug 2024 08:53:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.54 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724662440; cv=none; b=Y7B+4Q3MsET7XPCg0XwSviCKbjReVWCNmaHmbjOddS2CmCa1sM0tmcZIRq19TMAG9lpwdebGPlY2Nu2x2jj/RbSe5Tt9Xgf0+r910wmzLQhgR6agxjnDDfLq66Q+9i5XHiOMXN3e2x+u/YBYdQTMdLHqPWEtxHe8SWQaRppPFm4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724662440; c=relaxed/simple; bh=GuuW1WL+3o/YlrQrEDV2HHdlgrpjkOAllVC8EiRa6m0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=avLa3gnM9QNwVWzDSUOXuyVCud5houlk7QRQTA14PBXqGd/5KcGEAqKX67sC4DaO+w1XdvrUFwz8ta+6y98vsEciaI9dWu2KJtgOYPLVRfRIWrRKWUopXg/28u2XE+kSURYvSzA6QMv6Fd16mPLVdzmk8ALBeOBqhssosx7Wv2Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.208.54 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-ed1-f54.google.com with SMTP id 4fb4d7f45d1cf-5bebd3b7c22so8145687a12.0; Mon, 26 Aug 2024 01:53:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724662437; x=1725267237; 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=E4kEvuNqKI0xTjj6I4wqTHJS1sNMpYcp7Dr6Uq95pto=; b=IdCikk2emG+PWI0q1jcm03OzfrlnwITsbXVZ31CTCm7eIyRpeNqwlRX9EPW81867/i gS9153ZCKwgO6hfrXeetkgogGjMQoD5eoX7U+Fck2b1gj0I5ufVv7hLk/8muomOrRviu QVYY5hkoXkvq3MroKLxc8+A7oHpVhBBTMcJHTy11hbD9ipbL0p2V89NiHGHo8ObDIQ+u zUUqBzTmjviZjcQZfXVeqPuM/lF3nhOJjNVlC6pvfK+Gce+QGUpiTC1jAx8FvZqAOpD4 tfQas+QNg2NLx37pfR08uYUbhxMce0UBDVZt9WCp2LRyvcNJS0KaFl3EbSqmIYIear7m weLg== X-Forwarded-Encrypted: i=1; AJvYcCUIdyYbSANelapFh4QTlyg5Yzw6NGJPCroZL3QnloTxmRz7zr4w1OE9WeZTXcTj4ZVFUpmRKPCdfkFtdCym8Q==@vger.kernel.org, AJvYcCV9rsLteeQsiW0l5Y/ZPM7a7qg0IC71rht42Xeuv2J9+Utlk8TIdHv4U09dv4tDMRyj45F+G7/DkQSsj6AE@vger.kernel.org, AJvYcCX74Ar/o8KcMLn5Ryc4wgS0Py9KWrHCc2KTYQFwRZJat/5YSnQYcuDT0mAiASG3/I6eAW4nH5rlyI9X1NNBlEDzxmqcE1TO@vger.kernel.org, AJvYcCXCKN393U5jKXaOf5mR5ZK7CY8bzcOMvyDto1XY3XVg6Lv19nRs6ZkSuFQUVTUF4ZefXlP+uD105E7m+tF7ug==@vger.kernel.org X-Gm-Message-State: AOJu0YxhZ92FqSF8Vvl64R/BsxOglZMGu6adMamb73PTPXvKwInGgeR3 t4bk8i6Yr6tdNVPsZePyyE2FNwlndAfpzzAV+e95f8vzPx8gsIpL X-Google-Smtp-Source: AGHT+IF1fJpfy3mPNIRs30Wnajmd99gCu+0+b/DeTT6aTwMVnETwc04A+X+3AnJTgxAHcIGYmfyZ+g== X-Received: by 2002:a17:907:1c8e:b0:a75:7a8:d70c with SMTP id a640c23a62f3a-a86a2f14394mr1133364766b.4.1724662436552; Mon, 26 Aug 2024 01:53:56 -0700 (PDT) Received: from localhost.localdomain ([193.86.92.181]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a868f21fe18sm630636866b.29.2024.08.26.01.53.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Aug 2024 01:53:56 -0700 (PDT) From: Michal Hocko To: Andrew Morton Cc: Christoph Hellwig , Yafang Shao , Kent Overstreet , jack@suse.cz, Christian Brauner , Alexander Viro , Paul Moore , James Morris , "Serge E. Hallyn" , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-bcachefs@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Hocko Subject: [PATCH 2/2] mm: drop PF_MEMALLOC_NORECLAIM Date: Mon, 26 Aug 2024 10:47:13 +0200 Message-ID: <20240826085347.1152675-3-mhocko@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240826085347.1152675-1-mhocko@kernel.org> References: <20240826085347.1152675-1-mhocko@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Michal Hocko There is no existing user of the flag and the flag is dangerous because a nested allocation context can use GFP_NOFAIL which could cause unexpected failure. Such a code would be hard to maintain because it could be deeper in the call chain. PF_MEMALLOC_NORECLAIM has been added even when it was pointed out [1] that such a allocation contex is inherently unsafe if the context doesn't fully control all allocations called from this context. [1] https://lore.kernel.org/all/ZcM0xtlKbAOFjv5n@tiehlicka/ Signed-off-by: Michal Hocko Signed-off-by: Michal Hocko Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Vlastimil Babka --- include/linux/sched.h | 1 - include/linux/sched/mm.h | 7 ++----- 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index f8d150343d42..72dad3a6317a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1657,7 +1657,6 @@ extern struct pid *cad_pid; * I am cleaning dirty pages from some other bdi. */ #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ -#define PF_MEMALLOC_NORECLAIM 0x00800000 /* All allocation requests will clear __GFP_DIRECT_RECLAIM */ #define PF_MEMALLOC_NOWARN 0x01000000 /* All allocation requests will inherit __GFP_NOWARN */ #define PF__HOLE__02000000 0x02000000 #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index 91546493c43d..c49f2b24acb9 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -260,16 +260,13 @@ static inline gfp_t current_gfp_context(gfp_t flags) if (unlikely(pflags & (PF_MEMALLOC_NOIO | PF_MEMALLOC_NOFS | - PF_MEMALLOC_NORECLAIM | PF_MEMALLOC_NOWARN | PF_MEMALLOC_PIN))) { /* * Stronger flags before weaker flags: - * NORECLAIM implies NOIO, which in turn implies NOFS + * NOIO implies NOFS */ - if (pflags & PF_MEMALLOC_NORECLAIM) - flags &= ~__GFP_DIRECT_RECLAIM; - else if (pflags & PF_MEMALLOC_NOIO) + if (pflags & PF_MEMALLOC_NOIO) flags &= ~(__GFP_IO | __GFP_FS); else if (pflags & PF_MEMALLOC_NOFS) flags &= ~__GFP_FS;