From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6E69FC3DA7F for ; Mon, 12 Aug 2024 11:38:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D9B3D6B008A; Mon, 12 Aug 2024 07:38:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D4B446B008C; Mon, 12 Aug 2024 07:38:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C12D96B0092; Mon, 12 Aug 2024 07:38:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id A38BD6B008A for ; Mon, 12 Aug 2024 07:38:06 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 5D60C140A84 for ; Mon, 12 Aug 2024 11:38:06 +0000 (UTC) X-FDA: 82443394572.08.F273505 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf01.hostedemail.com (Postfix) with ESMTP id 8AAC140014 for ; Mon, 12 Aug 2024 11:38:03 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=14m6YEOJ; dmarc=none; spf=none (imf01.hostedemail.com: domain of BATV+1668c479149319e18fad+7659+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+1668c479149319e18fad+7659+infradead.org+hch@bombadil.srs.infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1723462673; a=rsa-sha256; cv=none; b=1MAkIHG/4CR/1gf1egTOdZyppR7mqcg0U4VVXMkQDmu9UHL8g9FAMwVp75kDdnBB31Huxy JImNcBHx3/2FBLp4lRqj9bJ4NIghRXVhR+khvOQD1HKjNCP9xq+wNMTQVKqFyNWmYbWKc0 3RdiATyNaGBbGj/a83UhEFwS0nN0gM4= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=14m6YEOJ; dmarc=none; spf=none (imf01.hostedemail.com: domain of BATV+1668c479149319e18fad+7659+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+1668c479149319e18fad+7659+infradead.org+hch@bombadil.srs.infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1723462673; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wksLjc1w9lLlhRmtEsxLy3ck/7gyi/wdT5KlFUNKhMY=; b=3fyCJxVAmSU9IPwCVUkbGJSaxSYPVzpw202PEwq/EP78+JALv/noBTy685wuO+V5Z50dG6 29VfdtUbHi/XyUvG0s/lkneiIZbBB7P6bkbkU3cLpYxk3i5Pt43wfVzQHzitOzW1haY6zG QOB2gpjm4tsCEahHAorTqOIttFLuzLk= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=wksLjc1w9lLlhRmtEsxLy3ck/7gyi/wdT5KlFUNKhMY=; b=14m6YEOJjEeU1KfSdarmpUSwrJ MB7K90gYapCa14q5bBMbLa2rdGAPdYYb0cZlIVtNvG24T7Zaa7PPkgGz2YuPrYQmmxg0MOBIimVxE OCZd3OIE2QfqJMsoxYmY6pAHGXqomcXWHL4o9VwJ0SkMtbIPFONvIVRj8pzCwzM6dGRogCibUkybN +ruLeLYFYzWqGHXbUE8huweFHEDQOLr2Wic4rkHpwpgSeVBuhqgYP1hrVJe47a3CSYCdtoc1bkIOn 2WTPYNieDsbPBYT7dNX6aL4fNlRaaV4FIxYY/+lShuxzPuZOWZeCM3QiikaSD3YuyL4BV8WFICgoK 7S6gxNqQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sdTN8-000000009PY-1yI7; Mon, 12 Aug 2024 11:37:58 +0000 Date: Mon, 12 Aug 2024 04:37:58 -0700 From: Christoph Hellwig To: Yafang Shao Cc: akpm@linux-foundation.org, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, david@fromorbit.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Kent Overstreet Subject: Re: [PATCH 1/2] mm: Add memalloc_nowait_{save,restore} Message-ID: References: <20240812090525.80299-1-laoar.shao@gmail.com> <20240812090525.80299-2-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240812090525.80299-2-laoar.shao@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Rspam-User: X-Rspamd-Queue-Id: 8AAC140014 X-Rspamd-Server: rspam01 X-Stat-Signature: gwbrkt9csjkqiqjk4jn3zto9ik7t455z X-HE-Tag: 1723462683-928013 X-HE-Meta: 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 iEwnH9ZS 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 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: On Mon, Aug 12, 2024 at 05:05:24PM +0800, Yafang Shao wrote: > The PF_MEMALLOC_NORECLAIM flag was introduced in commit eab0af905bfc > ("mm: introduce PF_MEMALLOC_NORECLAIM, PF_MEMALLOC_NOWARN"). To complement > this, let's add two helper functions, memalloc_nowait_{save,restore}, which > will be useful in scenarios where we want to avoid waiting for memory > reclamation. No, forcing nowait on callee contets is just asking for trouble. Unlike NOIO or NOFS this is incompatible with NOFAIL allocations and thus will lead to kernel crashes.