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 A5B75C54FB3 for ; Mon, 26 May 2025 06:35:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 263D06B007B; Mon, 26 May 2025 02:35:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 23B8D6B0082; Mon, 26 May 2025 02:35:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 179986B0089; Mon, 26 May 2025 02:35:42 -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 ECED06B007B for ; Mon, 26 May 2025 02:35:41 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 6D50A12016C for ; Mon, 26 May 2025 06:35:41 +0000 (UTC) X-FDA: 83484098082.21.F9D4EE5 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf04.hostedemail.com (Postfix) with ESMTP id AF27440004 for ; Mon, 26 May 2025 06:35:39 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1748241340; 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-transfer-encoding:content-transfer-encoding: in-reply-to:references; bh=xx8UQce5G1X0v9V8KkMFPofzo8dSpORDUL1PqfJD/AA=; b=8rL41ApjrTq/GEXqxVzibT8vhtdrY2y2qNPlbXnTmfOlsENQ/rozDkg27yO414whbw6S2K Pq7S8G+RR3jm2HHb2u/vP+++lgyL0yEpyUdU3lqFR7NvHTwNFjC11xfPqCRfM06e0naKVC zKvWwnQ8WTIBzQ3T0PglawTCLLjLOCY= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=none; spf=pass (imf04.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com; dmarc=pass (policy=none) header.from=arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1748241340; a=rsa-sha256; cv=none; b=IoCQ1ewXYJtyzKcUA6S5G6w7bL0MC1/GX5oemFKhqZ0cfwyNCVPH0clXPboMNqarhify6P s2O+ZrostOB5dCsSyDT3WzOEHZa+nTlItIV4kSFCzMafa3BVY+zNsockBsq1RnP+GeAsZS vBxuRLZtM7In80MvdNKWrk1WFdralEg= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 5004B153B; Sun, 25 May 2025 23:35:23 -0700 (PDT) Received: from MacBook-Pro.blr.arm.com (unknown [10.164.18.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id DECC53F5A1; Sun, 25 May 2025 23:35:35 -0700 (PDT) From: Dev Jain To: david@redhat.com, ziy@nvidia.com, willy@infradead.org, dhowells@redhat.com, hughd@google.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, aneesh.kumar@kernel.org Subject: [QUESTION] xas_reload() in iter_xarray_populate_pages() Date: Mon, 26 May 2025 12:05:24 +0530 Message-Id: <20250526063524.22597-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: AF27440004 X-Stat-Signature: un7qpf3o8whzdhyjwjrgoaqxrnond6t1 X-Rspam-User: X-HE-Tag: 1748241339-26403 X-HE-Meta: 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 tUVthQrt pp0/MVkX8Gn6Dg8uBCSQYNsSZBQdpr18h23Lxmw+7mynIb1NqfKyQpHpdXW7iJwx3DnLlnqnjUcj1y5EIOCq/2ZnkJReDx1UGnlvH 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: Hello all, After doing an xas_load() and xas_retry(), we take neither a reference nor a lock on the folio, and we do an xas_reload(). Is this just to reduce the time window for a race? If the above is true, then, there is a negligible window between xas_load() and xas_reload(), because only xas_retry() exists between them, so why to even reload()? Thanks, Dev