From: Jiexun Wang <wangjiexun@tinylab.org>
To: akpm@linux-foundation.org, brauner@kernel.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
falcon@tinylab.org, Jiexun Wang <wangjiexun@tinylab.org>
Subject: [PATCH 1/1] mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range()
Date: Sat, 9 Sep 2023 13:33:08 +0800 [thread overview]
Message-ID: <95d610623363009a71024c7a473d6895f39f3caf.1694219361.git.wangjiexun@tinylab.org> (raw)
In-Reply-To: <cover.1694219361.git.wangjiexun@tinylab.org>
Currently the madvise_cold_or_pageout_pte_range() function exhibits
significant latency under memory pressure, which can be effectively
reduced by adding cond_resched() within the loop.
When the batch_count reaches SWAP_CLUSTER_MAX, we reschedule
the task to ensure fairness and avoid long lock holding times.
Signed-off-by: Jiexun Wang <wangjiexun@tinylab.org>
---
mm/madvise.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/mm/madvise.c b/mm/madvise.c
index 4dded5d27e7e..df760096ea85 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -31,6 +31,7 @@
#include <linux/swapops.h>
#include <linux/shmem_fs.h>
#include <linux/mmu_notifier.h>
+#include <linux/swap.h>
#include <asm/tlb.h>
@@ -353,6 +354,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
struct folio *folio = NULL;
LIST_HEAD(folio_list);
bool pageout_anon_only_filter;
+ unsigned int batch_count = 0;
if (fatal_signal_pending(current))
return -EINTR;
@@ -441,6 +443,13 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
arch_enter_lazy_mmu_mode();
for (; addr < end; pte++, addr += PAGE_SIZE) {
ptent = ptep_get(pte);
+
+ if (++batch_count == SWAP_CLUSTER_MAX) {
+ pte_unmap_unlock(start_pte, ptl);
+ cond_resched();
+ start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ batch_count = 0;
+ }
if (pte_none(ptent))
continue;
--
2.34.1
next prev parent reply other threads:[~2023-09-09 5:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-09 5:33 [PATCH 0/1] mm/madvise: add cond_resched() in madvise_cold_or_pageout_pte_range() Jiexun Wang
2023-09-09 5:33 ` Jiexun Wang [this message]
2023-09-10 19:33 ` [PATCH 1/1] " Andrew Morton
2023-09-11 6:40 kernel test robot
2023-09-12 17:58 ` kernel test robot
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