Messages in this thread Patch in this message | | | Date | Tue, 7 Sep 2021 09:55:55 -0700 | From | Minchan Kim <> | Subject | Re: [LKP] Re: [mm] 8cc621d2f4: fio.write_iops -21.8% regression |
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Hi,
On Fri, Sep 03, 2021 at 03:11:33PM +0800, Xing, Zhengjun wrote: > Hi Minchan, > > Do you have time to look at this? I re-test it in v5.14, the regression > still existed. Thanks.
Reminding me the issue, again, Xing. That's because the patch was not merged yet so let me send it again.
Andrew?
From 8caadeb49d82403a08643dfbdb0b7749017c00bb Mon Sep 17 00:00:00 2001 From: Minchan Kim <minchan@kernel.org> Date: Tue, 25 May 2021 08:19:17 -0700 Subject: [PATCH] mm: fs: invalidate bh_lrus for only cold path
kernel test robot reported the regression of fio.write_iops[1] with [2].
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).
[1] https://lore.kernel.org/lkml/20210520083144.GD14190@xsang-OptiPlex-9020/ [2] 8cc621d2f45d, mm: fs: invalidate BH LRU during page migration Cc: Xing, Zhengjun <zhengjun.xing@intel.com> Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org> Reported-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Minchan Kim <minchan@kernel.org> --- mm/swap.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/mm/swap.c b/mm/swap.c index 1958d5feb148..3e25d99a9dbb 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -642,7 +642,6 @@ void lru_add_drain_cpu(int cpu) pagevec_lru_move_fn(pvec, lru_lazyfree_fn);
activate_page_drain(cpu); - invalidate_bh_lrus_cpu(cpu); }
/** @@ -725,6 +724,17 @@ void lru_add_drain(void) local_unlock(&lru_pvecs.lock); }
+static void lru_add_and_bh_lrus_drain(void) +{ + int cpu; + + local_lock(&lru_pvecs.lock); + cpu = smp_processor_id(); + lru_add_drain_cpu(cpu); + local_unlock(&lru_pvecs.lock); + invalidate_bh_lrus_cpu(cpu); +} + void lru_add_drain_cpu_zone(struct zone *zone) { local_lock(&lru_pvecs.lock); @@ -739,7 +749,7 @@ static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
static void lru_add_drain_per_cpu(struct work_struct *dummy) { - lru_add_drain(); + lru_add_and_bh_lrus_drain(); }
/* @@ -880,7 +890,7 @@ void lru_cache_disable(void) */ __lru_add_drain_all(true); #else - lru_add_drain(); + lru_add_and_bh_lrus_drain(); #endif }
-- 2.31.1.818.g46aad6cb9e-goog
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