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Shutemov" , Zi Yan , Matthew Wilcox , Andrew Morton , Linux MM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 7CA43104630F X-Stat-Signature: n9yc4uedgdg8j3k6zgqwmu7knfy3jypn Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=L8efeLnG; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf13.hostedemail.com: domain of shy828301@gmail.com designates 209.85.208.53 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-HE-Tag: 1637693509-771459 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Nov 23, 2021 at 9:47 AM Shakeel Butt wrote: > > The deferred THPs are split on memory pressure through shrinker > callback and splitting of THP during reclaim can fail for several > reasons like unable to lock the THP, under writeback or unexpected > number of pins on the THP. Such pages are put back on the deferred split > list for consideration later. However kernel does not update the > deferred queue size on putting back the pages whose split was failed. > This patch fixes that. > > Fixes: 364c1eebe453 ("mm: thp: extract split_queue_* into a struct") > Signed-off-by: Shakeel Butt > --- > mm/huge_memory.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index e5483347291c..4fff9584815b 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2809,7 +2809,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > unsigned long flags; > LIST_HEAD(list), *pos, *next; > struct page *page; > - int split = 0; > + unsigned long split = 0, num = 0; > > #ifdef CONFIG_MEMCG > if (sc->memcg) > @@ -2823,6 +2823,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > page = compound_head(page); > if (get_page_unless_zero(page)) { > list_move(page_deferred_list(page), &list); > + num++; Thanks for catching this. But I don't think "num" is needed, isn't the below code good enough? diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e5483347291c..1fbd8299db0c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2847,6 +2847,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, spin_lock_irqsave(&ds_queue->split_queue_lock, flags); list_splice_tail(&list, &ds_queue->split_queue); + ds_queue->split_queue_len -= split; spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); /* > } else { > /* We lost race with put_compound_page() */ > list_del_init(page_deferred_list(page)); > @@ -2847,6 +2848,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, > > spin_lock_irqsave(&ds_queue->split_queue_lock, flags); > list_splice_tail(&list, &ds_queue->split_queue); > + ds_queue->split_queue_len += (num - split); > spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); > > /* > -- > 2.34.0.rc2.393.gf8c9666880-goog >