Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt

From	Minchan Kim <minchan@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt
Date	2017-07-31 09:50 +0200
Message-ID	<u9dCF-3sb-5@gated-at.bofh.it> (permalink)
References	<u8gMi-6gp-13@gated-at.bofh.it> <u8hoZ-6JP-15@gated-at.bofh.it> <u8kZA-Mn-11@gated-at.bofh.it> <u94J4-6aS-9@gated-at.bofh.it> <u9d9D-3ia-3@gated-at.bofh.it>
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On Mon, Jul 31, 2017 at 09:17:07AM +0200, Christoph Hellwig wrote:
> On Mon, Jul 31, 2017 at 07:16:59AM +0900, Minchan Kim wrote:
> > rw_page's gain is reducing of dynamic allocation in swap path
> > as well as performance gain thorugh avoiding bio allocation.
> > And it would be important in memory pressure situation.
> 
> There is no need for any dynamic allocation when using the bio
> path.  Take a look at __blkdev_direct_IO_simple for an example
> that doesn't do any allocations.

Do you suggest define something special flag(e.g., SWP_INMEMORY)
for in-memory swap to swap_info_struct when swapon time manually
or from bdi_queue_someting automatically?
And depending the flag of swap_info_struct, use the onstack bio
instead of dynamic allocation if the swap device is in-memory?

Thread

[PATCH 0/3] remove rw_page() from brd, pmem and btt Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-07-28 19:00 +0200
  [PATCH 1/3] btt: remove btt_rw_page() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-07-28 19:00 +0200
  [PATCH 2/3] pmem: remove pmem_rw_page() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-07-28 19:10 +0200
  [PATCH 3/3] brd: remove brd_rw_page() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-07-28 19:10 +0200
  Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Matthew Wilcox <willy@infradead.org> - 2017-07-28 19:40 +0200
    Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Andrew Morton <akpm@linux-foundation.org> - 2017-07-28 23:30 +0200
      Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-07-31 00:20 +0200
        Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-07-31 00:40 +0200
        Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Christoph Hellwig <hch@lst.de> - 2017-07-31 09:20 +0200
          Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-07-31 09:50 +0200
            Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Christoph Hellwig <hch@lst.de> - 2017-07-31 09:50 +0200
              Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-01 08:30 +0200
            Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Christoph Hellwig <hch@lst.de> - 2017-07-31 09:50 +0200
    Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-08-03 00:20 +0200
      Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-03 02:20 +0200
        Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Dan Williams <dan.j.williams@intel.com> - 2017-08-03 02:40 +0200
        Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Christoph Hellwig <hch@lst.de> - 2017-08-03 10:10 +0200
          Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-04 03:00 +0200
        Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-08-03 23:20 +0200
          Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Jens Axboe <axboe@kernel.dk> - 2017-08-03 23:20 +0200
          Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-04 06:00 +0200
            Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-04 10:20 +0200
              Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Dan Williams <dan.j.williams@intel.com> - 2017-08-04 20:10 +0200
                Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-08-04 20:30 +0200
                Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Dan Williams <dan.j.williams@intel.com> - 2017-08-04 20:30 +0200
                Re: [PATCH 0/3] remove rw_page() from brd, pmem and btt Minchan Kim <minchan@kernel.org> - 2017-08-07 10:30 +0200

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