From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Henry Burns <henryburns@google.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Shakeel Butt <shakeelb@google.com>,
Jonathan Adams <jwadams@google.com>,
HenryBurns <henrywolfeburns@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2 v2] mm/zsmalloc.c: Migration can leave pages in ZS_EMPTY indefinitely
Date: Tue, 20 Aug 2019 11:53:07 +0900 [thread overview]
Message-ID: <20190820025307.GC500@jagdpanzerIV> (raw)
In-Reply-To: <20190809181751.219326-1-henryburns@google.com>
On (08/09/19 11:17), Henry Burns wrote:
> In zs_page_migrate() we call putback_zspage() after we have finished
> migrating all pages in this zspage. However, the return value is ignored.
> If a zs_free() races in between zs_page_isolate() and zs_page_migrate(),
> freeing the last object in the zspage, putback_zspage() will leave the page
> in ZS_EMPTY for potentially an unbounded amount of time.
>
> To fix this, we need to do the same thing as zs_page_putback() does:
> schedule free_work to occur. To avoid duplicated code, move the
> sequence to a new putback_zspage_deferred() function which both
> zs_page_migrate() and zs_page_putback() call.
>
> Fixes: 48b4800a1c6a ("zsmalloc: page migration support")
> Signed-off-by: Henry Burns <henryburns@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+ Andrew
-ss
prev parent reply other threads:[~2019-08-20 2:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 18:17 Henry Burns
2019-08-09 18:17 ` [PATCH 2/2 v2] mm/zsmalloc.c: Fix race condition in zs_destroy_pool Henry Burns
2019-08-20 2:59 ` Sergey Senozhatsky
2019-08-22 23:23 ` Andrew Morton
2019-08-23 8:10 ` Henry Burns
2019-08-26 5:13 ` Sergey Senozhatsky
2019-08-20 2:53 ` Sergey Senozhatsky [this message]
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