From: Vitaly Wool <vitalywool@gmail.com>
To: 김종석 <ks77sj@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] z3fold: fix wrong handling of headless pages
Date: Tue, 6 Nov 2018 08:48:39 +0100 [thread overview]
Message-ID: <CAMJBoFPGZ_pYFQTXb06U4QxM1ibUhmdxr6efwZigXdUo=4S=Vw@mail.gmail.com> (raw)
In-Reply-To: <1530853846-30215-1-git-send-email-ks77sj@gmail.com>
Hi Jongseok,
Den fre 6 juli 2018 kl 07:11 skrev Jongseok Kim <ks77sj@gmail.com>:
>
> During the processing of headless pages in z3fold_reclaim_page(),
> there was a problem that the zhdr pointed to another page
> or a page was already released in z3fold_free(). So, the wrong page
> is encoded in headless, or test_bit does not work properly
> in z3fold_reclaim_page(). This patch fixed these problems.
thank you for your work, we've now got a more comprehensive solution:
https://lkml.org/lkml/2018/11/5/726
Would you please confirm that it works for you? Also, would you be
okay with dropping your patch in favor of the new one?
~Vitaly
> Signed-off-by: Jongseok Kim <ks77sj@gmail.com>
> ---
> mm/z3fold.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/mm/z3fold.c b/mm/z3fold.c
> index 4b366d1..201a8ac 100644
> --- a/mm/z3fold.c
> +++ b/mm/z3fold.c
> @@ -746,6 +746,9 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
> }
>
> if (bud == HEADLESS) {
> + if (test_bit(UNDER_RECLAIM, &page->private))
> + return;
> +
> spin_lock(&pool->lock);
> list_del(&page->lru);
> spin_unlock(&pool->lock);
> @@ -836,20 +839,20 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
> }
> list_for_each_prev(pos, &pool->lru) {
> page = list_entry(pos, struct page, lru);
> + zhdr = page_address(page);
> if (test_bit(PAGE_HEADLESS, &page->private))
> /* candidate found */
> break;
>
> - zhdr = page_address(page);
> if (!z3fold_page_trylock(zhdr))
> continue; /* can't evict at this point */
> kref_get(&zhdr->refcount);
> list_del_init(&zhdr->buddy);
> zhdr->cpu = -1;
> - set_bit(UNDER_RECLAIM, &page->private);
> break;
> }
>
> + set_bit(UNDER_RECLAIM, &page->private);
> list_del_init(&page->lru);
> spin_unlock(&pool->lock);
>
> @@ -898,6 +901,7 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
> if (test_bit(PAGE_HEADLESS, &page->private)) {
> if (ret == 0) {
> free_z3fold_page(page);
> + atomic64_dec(&pool->pages_nr);
> return 0;
> }
> spin_lock(&pool->lock);
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-11-06 7:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-06 5:10 [PATCH] z3fold: fix wrong handling of headless pages Jongseok Kim
2018-11-06 7:48 ` Vitaly Wool [this message]
2018-11-08 12:26 ` 김종석
2018-11-08 12:34 ` 김종석
2018-11-08 12:57 ` Vitaly Wool
2018-11-08 13:45 ` Jongseok Kim
2018-11-08 22:23 ` Andrew Morton
2018-11-08 22:33 ` Vitaly Wool
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