linux-kernel - Re: [PATCH v3] zsmalloc: zs_page_migrate: schedule free_work if zspage is ZS

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Date:   Wed, 16 Aug 2017 13:01:08 +0900
From:   Minchan Kim <minchan@...nel.org>
To:     Hui Zhu <zhuhui@...omi.com>
Cc:     ngupta@...are.org, sergey.senozhatsky.work@...il.com,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        teawater@...il.com
Subject: Re: [PATCH v3] zsmalloc: zs_page_migrate: schedule free_work if
 zspage is ZS_EMPTY

On Wed, Aug 16, 2017 at 11:19:41AM +0800, Hui Zhu wrote:
> After commit [1] zs_page_migrate can handle the ZS_EMPTY zspage.
> 
> But I got some false in zs_page_isolate:
> 	if (get_zspage_inuse(zspage) == 0) {
> 		spin_unlock(&class->lock);
> 		return false;
> 	}
> The page of this zspage was migrated in before.
> 
> The reason is commit [1] just handle the "page" but not "newpage"
> then it keep the "newpage" with a empty zspage inside system.
> Root cause is zs_page_isolate remove it from ZS_EMPTY list but not
> call zs_page_putback "schedule_work(&pool->free_work);".  Because
> zs_page_migrate done the job without "schedule_work(&pool->free_work);"
> 
> Make this patch let zs_page_migrate wake up free_work if need.
> 
> [1] zsmalloc-zs_page_migrate-skip-unnecessary-loops-but-not-return-ebusy-if-zspage-is-not-inuse-fix.patch
> 
> Signed-off-by: Hui Zhu <zhuhui@...omi.com>
Acked-by: Minchan Kim <minchan@...nel.org>

Thanks!