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authorMinchan Kim <minchan@kernel.org>2021-09-24 15:43:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-09-24 16:13:35 -0700
commit243418e3925d5b5b0657ae54c322d43035e97eed (patch)
tree5cfbc50ba58f0bfca373305e2e9b233d3b35065d /fs/buffer.c
parentb7cd9fa5ccc392d9f2269edc4cb82508632c28da (diff)
downloadlinux-243418e3925d5b5b0657ae54c322d43035e97eed.tar.gz
mm: fs: invalidate bh_lrus for only cold path
The kernel test robot reported the regression of fio.write_iops[1] with commit 8cc621d2f45d ("mm: fs: invalidate BH LRU during page migration"). Since lru_add_drain is called frequently, invalidate bh_lrus there could increase bh_lrus cache miss ratio, which needs more IO in the end. This patch moves the bh_lrus invalidation from the hot path( e.g., zap_page_range, pagevec_release) to cold path(i.e., lru_add_drain_all, lru_cache_disable). Zhengjun Xing confirmed "I test the patch, the regression reduced to -2.9%" [1] https://lore.kernel.org/lkml/20210520083144.GD14190@xsang-OptiPlex-9020/ [2] 8cc621d2f45d, mm: fs: invalidate BH LRU during page migration Link: https://lkml.kernel.org/r/20210907212347.1977686-1-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: kernel test robot <oliver.sang@intel.com> Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org> Tested-by: "Xing, Zhengjun" <zhengjun.xing@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/buffer.c')
-rw-r--r--fs/buffer.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index ab7573d72dd7..c615387aedca 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1425,12 +1425,16 @@ void invalidate_bh_lrus(void)
}
EXPORT_SYMBOL_GPL(invalidate_bh_lrus);
-void invalidate_bh_lrus_cpu(int cpu)
+/*
+ * It's called from workqueue context so we need a bh_lru_lock to close
+ * the race with preemption/irq.
+ */
+void invalidate_bh_lrus_cpu(void)
{
struct bh_lru *b;
bh_lru_lock();
- b = per_cpu_ptr(&bh_lrus, cpu);
+ b = this_cpu_ptr(&bh_lrus);
__invalidate_bh_lrus(b);
bh_lru_unlock();
}