From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:46316 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932335AbdJZS26 (ORCPT ); Thu, 26 Oct 2017 14:28:58 -0400 Subject: Re: [PATCH v7 0/6] vfs: Use dlock list for SB's s_inodes list To: Alexander Viro , Jan Kara , Jeff Layton , "J. Bruce Fields" , Tejun Heo , Christoph Lameter Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Andi Kleen , Dave Chinner , Boqun Feng , Davidlohr Bueso References: <1507229008-20569-1-git-send-email-longman@redhat.com> From: Waiman Long Message-ID: <0c570c02-262e-a62a-9ba6-b1b451e53604@redhat.com> Date: Thu, 26 Oct 2017 14:28:55 -0400 MIME-Version: 1.0 In-Reply-To: <1507229008-20569-1-git-send-email-longman@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 10/05/2017 02:43 PM, Waiman Long wrote: > > This is a follow up of the following patchset: > > [PATCH v7 0/4] vfs: Use per-cpu list for SB's s_inodes list > https://lkml.org/lkml/2016/4/12/1009 > > This patchset provides new APIs for a set of distributed locked lists > (one/CPU core) to minimize lock and cacheline contention. Insertion > and deletion to the list will be cheap and relatively contention free. > Lookup, on the other hand, may be a bit more costly as there are > multiple lists to iterate. This is not really a problem for the > replacement of superblock's inode list by dlock list included in > the patchset as lookup isn't needed. > > For use cases that need to do lookup, the dlock list can also be > treated as a set of hashed lists that scales with the number of CPU > cores in the system. > > Both patches 5 and 6 are added to support other use cases like epoll > nested callbacks, for example, which could use the dlock-list to > reduce lock contention problem. > > Patch 1 introduces the dlock list. The list heads are allocated > by kcalloc() instead of percpu_alloc(). Each list head entry is > cacheline aligned to minimize contention. > > Patch 2 replaces the use of list_for_each_entry_safe() in > evict_inodes() and invalidate_inodes() by list_for_each_entry(). > > Patch 3 modifies the superblock and inode structures to use the dlock > list. The corresponding functions that reference those structures > are modified. > > Patch 4 makes the sibling CPUs use the same dlock list head to reduce > the number of list heads that need to be iterated. > > Patch 5 enables alternative use case of as a set of hashed lists. > > Patch 6 provides an irq safe mode specified at dlock-list allocation > time so that it can be within interrupt context. > > Jan Kara (1): > vfs: Remove unnecessary list_for_each_entry_safe() variants > > Waiman Long (5): > lib/dlock-list: Distributed and lock-protected lists > vfs: Use dlock list for superblock's inode list > lib/dlock-list: Make sibling CPUs share the same linked list > lib/dlock-list: Enable faster lookup with hashing > lib/dlock-list: Add an IRQ-safe mode to be used in interrupt handler > > fs/block_dev.c | 9 +- > fs/drop_caches.c | 9 +- > fs/inode.c | 38 +++--- > fs/notify/fsnotify.c | 9 +- > fs/quota/dquot.c | 14 +- > fs/super.c | 7 +- > include/linux/dlock-list.h | 245 ++++++++++++++++++++++++++++++++++ > include/linux/fs.h | 8 +- > lib/Makefile | 2 +- > lib/dlock-list.c | 322 +++++++++++++++++++++++++++++++++++++++++++++ > 10 files changed, 609 insertions(+), 54 deletions(-) > create mode 100644 include/linux/dlock-list.h > create mode 100644 lib/dlock-list.c > Is there other objections about merging this patch series? With the additional patches 8 & 9 that I sent out on Oct 17, I think I had addressed all the concerns that I received so far. Please let me know what else do I need to do to make these patches mergeable? Thanks, Longman