From: Johannes Weiner <hannes@cmpxchg.org>
To: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@fb.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Kernel-team@fb.com, mhocko@suse.com, hughd@google.com,
riel@redhat.com, mgorman@techsingularity.net,
akpm@linux-foundation.org
Subject: Re: [PATCH V4 4/6] mm: reclaim MADV_FREE pages
Date: Fri, 24 Feb 2017 10:36:55 -0500 [thread overview]
Message-ID: <20170224153655.GA20092@cmpxchg.org> (raw)
In-Reply-To: <20170224021218.GD9818@bbox>
On Fri, Feb 24, 2017 at 11:12:18AM +0900, Minchan Kim wrote:
> > @@ -1525,8 +1531,8 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
> >
> > if (ret != SWAP_MLOCK && !page_mapcount(page)) {
> > ret = SWAP_SUCCESS;
> > - if (rp.lazyfreed && !PageDirty(page))
> > - ret = SWAP_LZFREE;
> > + if (rp.lazyfreed && PageDirty(page))
> > + ret = SWAP_DIRTY;
>
> Hmm, I don't understand why we need to introduce new return value.
> Can't we set SetPageSwapBacked and return SWAP_FAIL in try_to_unmap_one?
I think that's a bad idea. A function called "try_to_unmap" shouldn't
have as a side effect that it changes the page's LRU type in an error
case. Let try_to_unmap be about unmapping the page. If it fails, make
it report why and let the caller deal with the fallout. Any LRU fixups
are much better placed in vmscan.c.
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next prev parent reply other threads:[~2017-02-24 15:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-22 18:50 [PATCH V4 0/6] mm: fix some MADV_FREE issues Shaohua Li
2017-02-22 18:50 ` [PATCH V4 1/6] mm: delete unnecessary TTU_* flags Shaohua Li
2017-02-23 15:35 ` Johannes Weiner
2017-02-24 1:25 ` Minchan Kim
2017-02-24 3:29 ` Hillf Danton
2017-02-22 18:50 ` [PATCH V4 2/6] mm: don't assume anonymous pages have SwapBacked flag Shaohua Li
2017-02-22 18:50 ` [PATCH V4 3/6] mm: move MADV_FREE pages into LRU_INACTIVE_FILE list Shaohua Li
2017-02-23 15:58 ` Johannes Weiner
2017-02-23 16:26 ` Shaohua Li
2017-02-23 18:22 ` Johannes Weiner
2017-02-23 19:04 ` Shaohua Li
2017-02-24 1:49 ` Minchan Kim
2017-02-24 6:15 ` Shaohua Li
2017-02-24 23:37 ` Minchan Kim
2017-02-22 18:50 ` [PATCH V4 4/6] mm: reclaim MADV_FREE pages Shaohua Li
2017-02-23 16:13 ` Johannes Weiner
2017-02-23 17:19 ` Shaohua Li
2017-02-24 2:12 ` Minchan Kim
2017-02-24 6:14 ` Shaohua Li
2017-02-24 15:36 ` Johannes Weiner [this message]
2017-02-24 23:26 ` Minchan Kim
2017-02-22 18:50 ` [PATCH V4 5/6] mm: enable MADV_FREE for swapless system Shaohua Li
2017-02-22 18:50 ` [PATCH V4 6/6] proc: show MADV_FREE pages info in smaps Shaohua Li
2017-02-23 16:16 ` Johannes Weiner
2017-02-24 2:13 ` Minchan Kim
2017-02-24 17:08 ` Dave Hansen
2017-02-24 21:47 ` Shaohua Li
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