From: Vineeth Pillai <vpillai@digitalocean.com>
To: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Huang Ying <ying.huang@intel.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Kelley Nielsen <kelleynnn@gmail.com>,
Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH v3 2/2] mm: rid swapoff of quadratic complexity
Date: Wed, 2 Jan 2019 15:05:25 -0500 [thread overview]
Message-ID: <CANaguZDcJa9NxZU4Z3Q7DqvQK5zsDXZKNbhbO8fcppnYrTxMHw@mail.gmail.com> (raw)
In-Reply-To: <alpine.LSU.2.11.1901021039490.13761@eggly.anvils>
On Wed, Jan 2, 2019 at 2:43 PM Hugh Dickins <hughd@google.com> wrote:
>
> Wrong. Without heavier locking that would add unwelcome overhead to
> common paths, we shall "always" need the retry logic. It does not
> come into play very often, but here are two examples of why it's
> needed (if I thought longer, I might find more). And in practice,
> yes, I sometimes saw 1 retry needed.
>
Understood. Sorry, I missed these corner cases.
> I don't use frontswap myself, and haven't paid any attention to the
> frontswap partial swapoff case (though notice now that shmem_unuse()
> lacks the plumbing needed for it - that needs fixing); but doubt it
> would be a good idea to refactor it out as a separate case.
>
I shall rework the shmem side to take care of the frontswap and retain
the retry logic in a simplified manner.
Thanks again for all the comments and insights..
~Vineeth
next prev parent reply other threads:[~2019-01-02 20:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-03 17:09 [PATCH v3 1/2] mm: Refactor swap-in logic out of shmem_getpage_gfp Vineeth Remanan Pillai
2018-12-03 17:09 ` [PATCH v3 2/2] mm: rid swapoff of quadratic complexity Vineeth Remanan Pillai
2019-01-01 0:44 ` Hugh Dickins
2019-01-01 0:44 ` Hugh Dickins
2019-01-01 18:24 ` Vineeth Pillai
2019-01-01 18:24 ` Vineeth Pillai
2019-01-02 4:16 ` Hugh Dickins
2019-01-02 4:16 ` Hugh Dickins
2019-01-02 17:47 ` Vineeth Pillai
2019-01-02 17:47 ` Vineeth Pillai
2019-01-02 19:43 ` Hugh Dickins
2019-01-02 19:43 ` Hugh Dickins
2019-01-02 20:05 ` Vineeth Pillai [this message]
2019-01-02 20:05 ` Vineeth Pillai
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