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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D0251C7EE37 for ; Fri, 9 Jun 2023 00:52:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237009AbjFIAwH (ORCPT ); Thu, 8 Jun 2023 20:52:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51616 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229477AbjFIAwF (ORCPT ); Thu, 8 Jun 2023 20:52:05 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0BE0E1FDF for ; Thu, 8 Jun 2023 17:52:04 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-568a8704f6dso16121097b3.1 for ; Thu, 08 Jun 2023 17:52:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686271923; x=1688863923; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=TthVOGU5NBXTdUCbenudXv/zsuPKI5dT0elSKLsw5KY=; b=ImpLDGn3lmP9gv5tkN/NEWkOq1CUqj8TD3qghFzsulypsFg5z+NBVRVHcl4W+zs9NS a/AUxP3USFFEem5uKIozHHNBnxBibW9dCIUuyoz/7IPe89xOljWkVvW9V6osOlolfUne DQLjQqvvd5IXZIwOo9ZRrUtWG6YL+hMBO0XMhyX9ft2y5anTxTVz9LsrpUIxcTGwDtT+ +rMTNXGaBaHLPmEulzNcpPMC8knZz8tOalmVU/5YVSXK0/OGPREjG3YZwobjrPaMaWCr SQOISk0fFfxmV88xE6geZP9//tFPMygeFZNtEH0SbRgZnobBVXTiCsqOvEWJz55HHPRP 8ZIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686271923; x=1688863923; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=TthVOGU5NBXTdUCbenudXv/zsuPKI5dT0elSKLsw5KY=; b=eExvxGZbVEGL79BV3ba1Xt0Lhd4tvNl5h56/OOiJMbLyh7IreA3AZDzB+irL/o8g92 TYgeQ2WPBt/mExXBkNhAgH3BsfF7kV2eKqEYE4MynLkL7m4FqMzZL78K2lnhZbX1ZO8o 8M/sZZDeRckHb2eBaFLnZ5Ojf/N/5QLCD50TsaP4A99b5+rBnaAquiJVkRE6l2jg6GVi KkakiI8/M/+Ex9oWx4XsMKgjJgDlRDbegG4Q6g1P3kWsK/VBPgHGRDiAU2WOLk3fbD9D y4CpYSRyd3aCOQypmFZalCcDPkrTj33eT6hjRHI0RmdZKSVxaOBhfVUgxiL8RLGWQG6q Rh6Q== X-Gm-Message-State: AC+VfDwj3+GaBDPJLQ4V2CHdK/uWcyPOUAFfHENvcWnfmjHsKDDZurOD EeLCs/XaJiJKQeyGUGr8p3TkyHyJ8oY= X-Google-Smtp-Source: ACHHUZ5NZ4g1X3BYYVvHaQ5ca+C3geF48LesY4562DfpiKDGzLPRjCuGKlBWzQoWjUktyTRs7xzqWuvyq0c= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:c03e:d3b7:767a:9467]) (user=surenb job=sendgmr) by 2002:a81:ac43:0:b0:568:9bcc:5e16 with SMTP id z3-20020a81ac43000000b005689bcc5e16mr712323ywj.2.1686271923250; Thu, 08 Jun 2023 17:52:03 -0700 (PDT) Date: Thu, 8 Jun 2023 17:51:52 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230609005158.2421285-1-surenb@google.com> Subject: [PATCH v2 0/6] Per-vma lock support for swap and userfaults From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: willy@infradead.org, hannes@cmpxchg.org, mhocko@suse.com, josef@toxicpanda.com, jack@suse.cz, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com, michel@lespinasse.org, liam.howlett@oracle.com, jglisse@google.com, vbabka@suse.cz, minchan@google.com, dave@stgolabs.net, punit.agrawal@bytedance.com, lstoakes@gmail.com, hdanton@sina.com, apopple@nvidia.com, peterx@redhat.com, ying.huang@intel.com, david@redhat.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, pasha.tatashin@soleen.com, surenb@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When per-vma locks were introduced in [1] several types of page faults would still fall back to mmap_lock to keep the patchset simple. Among them are swap and userfault pages. The main reason for skipping those cases was the fact that mmap_lock could be dropped while handling these faults and that required additional logic to be implemented. Implement the mechanism to allow per-vma locks to be dropped for these cases. When that happens handle_mm_fault returns new VM_FAULT_VMA_UNLOCKED vm_fault_reason bit along with VM_FAULT_RETRY to indicate that VMA lock was dropped. Naturally, once VMA lock is dropped that VMA should be assumed unstable and can't be used. Changes since v1 posted at [2] - New patch 1/6 to remove do_poll parameter from read_swap_cache_async(), per Huang Ying - New patch 3/6 to separate VM_FAULT_COMPLETED addition, per Alistair Popple - Added comment for VM_FAULT_VMA_UNLOCKED in 4/6, per Alistair Popple - New patch 6/6 to handle userfaults under VMA lock Note: I tried implementing Matthew's suggestion in [3] to add vmf_end_read but that gets quite messy since it would require changing code for every architecture when we change handle_mm_fault interface. Note: patch 4/6 will cause a trivial merge conflict in arch/arm64/mm/fault.c when applied over mm-unstable branch due to a patch from ARM64 tree [4] which is missing in mm-unstable. [1] https://lore.kernel.org/all/20230227173632.3292573-1-surenb@google.com/ [2] https://lore.kernel.org/all/20230501175025.36233-1-surenb@google.com/ [3] https://lore.kernel.org/all/ZFEeHqzBJ6iOsRN+@casper.infradead.org/ [4] https://lore.kernel.org/all/20230524131305.2808-1-jszhang@kernel.org/ Suren Baghdasaryan (6): swap: remove remnants of polling from read_swap_cache_async mm: handle swap page faults under VMA lock if page is uncontended mm: add missing VM_FAULT_RESULT_TRACE name for VM_FAULT_COMPLETED mm: drop VMA lock before waiting for migration mm: implement folio wait under VMA lock mm: handle userfaults under VMA lock arch/arm64/mm/fault.c | 3 ++- arch/powerpc/mm/fault.c | 3 ++- arch/s390/mm/fault.c | 3 ++- arch/x86/mm/fault.c | 3 ++- fs/userfaultfd.c | 42 ++++++++++++++++++----------------- include/linux/mm_types.h | 7 +++++- include/linux/pagemap.h | 14 ++++++++---- mm/filemap.c | 37 +++++++++++++++++++------------ mm/madvise.c | 4 ++-- mm/memory.c | 48 ++++++++++++++++++++++------------------ mm/swap.h | 1 - mm/swap_state.c | 12 +++++----- 12 files changed, 103 insertions(+), 74 deletions(-) -- 2.41.0.162.gfafddb0af9-goog