From patchwork Fri Oct 21 16:36:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Houghton X-Patchwork-Id: 13015090 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 1288AC433FE for ; Fri, 21 Oct 2022 16:37:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 15B448E0018; Fri, 21 Oct 2022 12:37:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0BD318E0001; Fri, 21 Oct 2022 12:37:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DB3B78E0018; Fri, 21 Oct 2022 12:37:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id C62298E0001 for ; Fri, 21 Oct 2022 12:37:38 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 8288AC0317 for ; Fri, 21 Oct 2022 16:37:38 +0000 (UTC) X-FDA: 80045512596.14.22C809B Received: from mail-yw1-f201.google.com (mail-yw1-f201.google.com [209.85.128.201]) by imf16.hostedemail.com (Postfix) with ESMTP id 344DD180031 for ; Fri, 21 Oct 2022 16:37:38 +0000 (UTC) Received: by mail-yw1-f201.google.com with SMTP id 00721157ae682-36ab1ae386bso3387167b3.16 for ; Fri, 21 Oct 2022 09:37:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=A8A4WdJUmtZ3pZn0W1kJeWoXW7oHHPnmlapm5XaH58o=; b=QyZNlwrSq5mo4QWYzR3oK0EIR216wpexI9Df6hEZNyICuoeMeDmrMlBrvBhG5G9oMH eDwoSKuwVOkw2F+eA1UKjuSgQ/4G0YaIvKDgPK5/l7J3Q8CkdNBISRGJo0HwWGWEUNrf Hsg26jVqMIfXyFuiBuWIPRk3e/w2Ynh00CNLcq8RUWHyxHLWPosuj8ILf6dtKr/srDKf VgnkAvfVFAk1eD2bIu3KwtmPY4idqkPwVNcFidZU4Qvqi2ndAMirEsPVmZ++CLhMi7or QE1FxE7zy+/P5OQx3hmNlYrC8AT26Ti6pHfMan5PLEwpAZLEhxJr4VhMjlaxssiD5v+m jbDw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=A8A4WdJUmtZ3pZn0W1kJeWoXW7oHHPnmlapm5XaH58o=; b=sZTkeHwfPYqYFJ+8r41jlGVTWRoPXPSEOp6cuk07N1s01wrfDg/ipwHC2TKANf2h3Y /waXRKuu27kAUMl2tEevSpO+RI0pg1/qOE1atO65zyutGTHVry03nIh2bzf26rEqBJGX PckDI6iUqbytoiSdCZcMhA9IoGFr8StTKHrCO1ZNlydQJQ5DowtDIFE6aK6lhdaHwWjp q3f6PBSrHcdSICxOLBP6CcJEc+2SOHb/agTEXwmlTXEXexlXPUdNEIgquUCSgF5NunBQ jv65b3pWvg0QlEcvRt48TYWz7Xn02aiZ2enXVH7/YxGujNoOsCxSR25qjBD6Z9Ml6S4X qPkg== X-Gm-Message-State: ACrzQf1cjDfmJUM2gAlTO9yRigF7inR8s8BQyPSctVhQny/mtD2w3J64 zG8kkdjHTE0oYR7zDLcxZB+8BCCVQoqQxEIB X-Google-Smtp-Source: AMsMyM7mqFcWFty/hD8NAlbP6ayFKJzD6/8Ky2ha3bC8YyWht+9XnIfNeF0UVQPRo5YyUUff1SZwDTyeE2m4y1Pj X-Received: from jthoughton.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2a4f]) (user=jthoughton job=sendgmr) by 2002:a25:cd45:0:b0:6c2:2d8a:e3f4 with SMTP id d66-20020a25cd45000000b006c22d8ae3f4mr17406990ybf.395.1666370257496; Fri, 21 Oct 2022 09:37:37 -0700 (PDT) Date: Fri, 21 Oct 2022 16:36:39 +0000 In-Reply-To: <20221021163703.3218176-1-jthoughton@google.com> Mime-Version: 1.0 References: <20221021163703.3218176-1-jthoughton@google.com> X-Mailer: git-send-email 2.38.0.135.g90850a2211-goog Message-ID: <20221021163703.3218176-24-jthoughton@google.com> Subject: [RFC PATCH v2 23/47] rmap: update hugetlb lock comment for HGM From: James Houghton To: Mike Kravetz , Muchun Song , Peter Xu Cc: David Hildenbrand , David Rientjes , Axel Rasmussen , Mina Almasry , "Zach O'Keefe" , Manish Mishra , Naoya Horiguchi , "Dr . David Alan Gilbert" , "Matthew Wilcox (Oracle)" , Vlastimil Babka , Baolin Wang , Miaohe Lin , Yang Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, James Houghton ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666370258; 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=A8A4WdJUmtZ3pZn0W1kJeWoXW7oHHPnmlapm5XaH58o=; b=vPSlbPKv/MwrAwJJmWw7GwLgiLwqV53cdW/ZxNkDM58jleGiSJ8H4tQ8002QsAXdQAarQe pYEpDuSiKOqdJB/qDveymLXABWVBOej4QMf80yQUAn28nfEIC9hPwwyOMU4KerYUx5ib9v HyQ1E8Xkx3jfWM2Z4NtCtK6yTn2AD60= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=QyZNlwrS; spf=pass (imf16.hostedemail.com: domain of 30cpSYwoKCNI7H5CI45HCB4CC492.0CA96BIL-AA8Jy08.CF4@flex--jthoughton.bounces.google.com designates 209.85.128.201 as permitted sender) smtp.mailfrom=30cpSYwoKCNI7H5CI45HCB4CC492.0CA96BIL-AA8Jy08.CF4@flex--jthoughton.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1666370258; a=rsa-sha256; cv=none; b=ig7bV9tv5kP3JMkKsuB7EYZ+VW2fzibPWsWJA2oljio0BSS9uyxk3woYAe9l9bSZntt9Dt wlT3ZXnsNXHT3uCp0PBVcvGHLZHQFWmcHsVdqOZLRGsawX+kLn+UlOL2qmQkNzAgxTkOWX j8UsgseK+kmzrVOxAUIJhTyrs91X8aA= X-Stat-Signature: y94c6ghombpwigof4kuc8gpo1mzdp4w9 X-Rspam-User: Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=QyZNlwrS; spf=pass (imf16.hostedemail.com: domain of 30cpSYwoKCNI7H5CI45HCB4CC492.0CA96BIL-AA8Jy08.CF4@flex--jthoughton.bounces.google.com designates 209.85.128.201 as permitted sender) smtp.mailfrom=30cpSYwoKCNI7H5CI45HCB4CC492.0CA96BIL-AA8Jy08.CF4@flex--jthoughton.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 344DD180031 X-HE-Tag: 1666370258-620597 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: The VMA lock is used to prevent high-granularity HugeTLB mappings from being collapsed while other threads are doing high-granularity page table walks. Signed-off-by: James Houghton --- mm/rmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/rmap.c b/mm/rmap.c index 19850d955aea..527463c1e936 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -47,7 +47,8 @@ * * hugetlbfs PageHuge() take locks in this order: * hugetlb_fault_mutex (hugetlbfs specific page fault mutex) - * vma_lock (hugetlb specific lock for pmd_sharing) + * vma_lock (hugetlb specific lock for pmd_sharing and high-granularity + * mapping) * mapping->i_mmap_rwsem (also used for hugetlb pmd sharing) * page->flags PG_locked (lock_page) */