From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Waiman Long To: Alexander Viro , Jonathan Corbet Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, "Luis R. Rodriguez" , Kees Cook , Linus Torvalds , Jan Kara , "Paul E. McKenney" , Andrew Morton , Ingo Molnar , Miklos Szeredi , Matthew Wilcox , Larry Woodman , James Bottomley , "Wangkai (Kevin C)" , Michal Hocko , Waiman Long Subject: [PATCH v3 0/4] fs/dcache: Track # of negative dentries Date: Tue, 11 Sep 2018 15:18:22 -0400 Message-Id: <1536693506-11949-1-git-send-email-longman@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: v2->v3: - With confirmation that the dummy array in dentry_stat structure was never a replacement of a previously used field, patch 3 is now reverted back to use one of dummy field as the negative dentry count instead of adding a new field. v1->v2: - Clarify what the new nr_dentry_negative per-cpu counter is tracking and open-code the increment and decrement as suggested by Dave Chinner. - Append the new nr_dentry_negative count as the 7th element of dentry-state instead of replacing one of the dummy entries. - Remove patch "fs/dcache: Make negative dentries easier to be reclaimed" for now as I need more time to think about what to do with it. - Add 2 more patches to address issues found while reviewing the dentry code. - Add another patch to change the conditional branch of nr_dentry_negative accounting to conditional move so as to reduce the performance impact of the accounting code. This patchset addresses 2 issues found in the dentry code and adds a new nr_dentry_negative per-cpu counter to track the total number of negative dentries in all the LRU lists. Patch 1 fixes a bug in the accounting of nr_dentry_unused in shrink_dcache_sb(). Patch 2 removes the ____cacheline_aligned_in_smp tag from super_block LRU lists. Patch 3 adds the new nr_dentry_negative per-cpu counter. Patch 4 removes conditional branches in nr_dentry_negative accounting code. Various filesystem related tests were run and no statistically significant changes in performance was observed. Waiman Long (4): fs/dcache: Fix incorrect nr_dentry_unused accounting in shrink_dcache_sb() fs: Don't need to put list_lru into its own cacheline fs/dcache: Track & report number of negative dentries fs/dcache: Eliminate branches in nr_dentry_negative accounting Documentation/sysctl/fs.txt | 26 +++++++++++++--------- fs/dcache.c | 54 ++++++++++++++++++++++++++++++++++++++++----- include/linux/dcache.h | 7 +++--- include/linux/fs.h | 9 ++++---- 4 files changed, 74 insertions(+), 22 deletions(-) -- 1.8.3.1