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 X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1973C43331 for ; Thu, 26 Mar 2020 07:02:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4DFD20719 for ; Thu, 26 Mar 2020 07:02:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="S+rb2gtq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727590AbgCZHCo (ORCPT ); Thu, 26 Mar 2020 03:02:44 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:42272 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726332AbgCZHCo (ORCPT ); Thu, 26 Mar 2020 03:02:44 -0400 Received: by mail-pf1-f202.google.com with SMTP id j2so4422345pfh.9 for ; Thu, 26 Mar 2020 00:02:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=xxvyxjj91melXa2f3O0p5YGO5yfdIf2InM2lDPE9tIk=; b=S+rb2gtqH3Mle1QzHX8tBmJKYQt8IOQhCKT8GNmojRB6bUWcTc2zCtEYWPPOXh3raR KfZuAnS5qLywjBjfFSZFvlD52vx1ktBHNB1BFhpeqkugFuvfrI16BTHF0FtoUHxZ0dVp TQE6+Lykq+FwLKbyOHFBMTwlVg6LYtJquwrx3qIGfrIBCU8YK9i/h0LiHp2l6wRGigxz u4N/9klDmr3UAS3arA9uDAqhoxX+eqe6xy6jeIKwbl5GBEmcAVfJ2hWexeJYL1YyJfsv wCmSV830WdwO6IkvYg1rF0EXNVgfBv1p4nzSZZoY7E9hn1SdoY4nSiy8A2oQc4AgD8dE gCXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=xxvyxjj91melXa2f3O0p5YGO5yfdIf2InM2lDPE9tIk=; b=FsbAhHtvcLSM7Dc0+zIy0ypU9y3kb26OM+5seHca3Q+BVRrkIxtdreBpqNNRjOYbJA gQoaz4X6w0CSj4eaFfHS4NWb6q+l+xzo9/HbnXODWMz2n+DwMZTIE4tMF2Sn35LjPooY KxWmtp1QHMNQnkbFrvbBgqWj+mQlf0em6gvp6lNQIqGU45n03IfnTHCdO8vBt2AcSeze XzdPSUVm59rNniJjxe5Jgl/nCjk8ZWNJCcZ+KDJ20gReavZh///5/I20CLaWZ6ts7rW6 oOvIH2+ixxFm/G7s666MBju7J7/NUbK+dPomQ9ey9wk+w6NU1QNmvTJbfE2ZrprHmHWw EE2A== X-Gm-Message-State: ANhLgQ11+SxT79UU1jl0e4Ic5JdhnUMP08KnF00N66HdfTd18rlVSwPy D0sy/Hcc0wfu1ED8bPc5+TzKtzzmsP8= X-Google-Smtp-Source: ADFU+vtNeNSXu+zk+G9qTMevsl/EO/OZ7hP+2bvX9a40agCXFI6f7Ltq/McjSMLAed50Ejoy3tAOmtow6I0= X-Received: by 2002:a17:90a:5d16:: with SMTP id s22mr1610999pji.118.1585206161146; Thu, 26 Mar 2020 00:02:41 -0700 (PDT) Date: Thu, 26 Mar 2020 00:02:29 -0700 In-Reply-To: <20200326070236.235835-1-walken@google.com> Message-Id: <20200326070236.235835-2-walken@google.com> Mime-Version: 1.0 References: <20200326070236.235835-1-walken@google.com> X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH 1/8] mmap locking API: initial implementation as rwsem wrappers From: Michel Lespinasse To: Andrew Morton , linux-mm Cc: LKML , Peter Zijlstra , Laurent Dufour , Vlastimil Babka , Matthew Wilcox , Liam Howlett , Jerome Glisse , Davidlohr Bueso , David Rientjes , Hugh Dickins , Ying Han , Michel Lespinasse Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This change wraps the existing mmap_sem related rwsem calls into a new mmap locking API. There are two justifications for the new API: - At first, it provides an easy hooking point to instrument mmap_sem locking latencies independently of any other rwsems. - In the future, it may be a starting point for replacing the rwsem implementation with a different one, such as range locks. Signed-off-by: Michel Lespinasse --- include/linux/mm.h | 1 + include/linux/mmap_lock.h | 59 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 60 insertions(+) create mode 100644 include/linux/mmap_lock.h diff --git a/include/linux/mm.h b/include/linux/mm.h index c54fb96cb1e6..2f13c9198999 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h new file mode 100644 index 000000000000..cffd25afe92b --- /dev/null +++ b/include/linux/mmap_lock.h @@ -0,0 +1,59 @@ +#ifndef _LINUX_MMAP_LOCK_H +#define _LINUX_MMAP_LOCK_H + +static inline void mmap_init_lock(struct mm_struct *mm) +{ + init_rwsem(&mm->mmap_sem); +} + +static inline void mmap_write_lock(struct mm_struct *mm) +{ + down_write(&mm->mmap_sem); +} + +static inline int mmap_write_lock_killable(struct mm_struct *mm) +{ + return down_write_killable(&mm->mmap_sem); +} + +static inline bool mmap_write_trylock(struct mm_struct *mm) +{ + return down_write_trylock(&mm->mmap_sem) != 0; +} + +static inline void mmap_write_unlock(struct mm_struct *mm) +{ + up_write(&mm->mmap_sem); +} + +static inline void mmap_downgrade_write_lock(struct mm_struct *mm) +{ + downgrade_write(&mm->mmap_sem); +} + +static inline void mmap_read_lock(struct mm_struct *mm) +{ + down_read(&mm->mmap_sem); +} + +static inline int mmap_read_lock_killable(struct mm_struct *mm) +{ + return down_read_killable(&mm->mmap_sem); +} + +static inline bool mmap_read_trylock(struct mm_struct *mm) +{ + return down_read_trylock(&mm->mmap_sem) != 0; +} + +static inline void mmap_read_unlock(struct mm_struct *mm) +{ + up_read(&mm->mmap_sem); +} + +static inline bool mmap_is_locked(struct mm_struct *mm) +{ + return rwsem_is_locked(&mm->mmap_sem) != 0; +} + +#endif /* _LINUX_MMAP_LOCK_H */ -- 2.25.1.696.g5e7596f4ac-goog