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From: Nikolay Borisov <nborisov@suse.com>
To: Qu Wenruo <wqu@suse.com>, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v2 03/19] btrfs: calculate inline extent buffer page size based on page size
Date: Tue, 15 Sep 2020 11:35:44 +0300	[thread overview]
Message-ID: <acd4c9ff-841e-1449-7253-222d5469967d@suse.com> (raw)
In-Reply-To: <20200915053532.63279-4-wqu@suse.com>



On 15.09.20 г. 8:35 ч., Qu Wenruo wrote:
> Btrfs only support 64K as max node size, thus for 4K page system, we
> would have at most 16 pages for one extent buffer.
> 
> For a system using 64K page size, we would really have just one
> single page.
> 
> While we always use 16 pages for extent_buffer::pages[], this means for
> systems using 64K pages, we are wasting memory for the 15 pages which
> will never be utilized.
> 
> So this patch will change how the extent_buffer::pages[] array size is
> calclulated, now it will be calculated using
> BTRFS_MAX_METADATA_BLOCKSIZE and PAGE_SIZE.
> 
> For systems using 4K page size, it will stay 16 pages.
> For systems using 64K page size, it will be just 1 page.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Nikolay Borisov <nborisov@suse.com>

<snip>

> diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
> index 00a88f2eb5ab..d511890702cc 100644
> --- a/fs/btrfs/extent_io.h
> +++ b/fs/btrfs/extent_io.h
> @@ -85,9 +85,11 @@ struct extent_io_ops {
>  				    int mirror);
>  };
>  
> -
> -#define INLINE_EXTENT_BUFFER_PAGES 16
> -#define MAX_INLINE_EXTENT_BUFFER_SIZE (INLINE_EXTENT_BUFFER_PAGES * PAGE_SIZE)
> +/*
> + * The SZ_64K is BTRFS_MAX_METADATA_BLOCKSIZE, here just to avoid circle
> + * including "ctree.h".
> + */
> +#define INLINE_EXTENT_BUFFER_PAGES (SZ_64K / PAGE_SIZE)

nit: Instead of doing this it would be better if this define is simply
moved next to BTRFS_MAX_METADATA_BLOCKSIZE so that every define relating
to eb's are clustered together.

>  struct extent_buffer {
>  	u64 start;
>  	unsigned long len;
> 

  reply	other threads:[~2020-09-15  8:35 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15  5:35 [PATCH v2 00/19] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 01/19] btrfs: extent-io-tests: remove invalid tests Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 02/19] btrfs: remove the unnecessary parameter @start and @len for check_data_csum() Qu Wenruo
2020-09-15  8:39   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 03/19] btrfs: calculate inline extent buffer page size based on page size Qu Wenruo
2020-09-15  8:35   ` Nikolay Borisov [this message]
2020-09-15 10:05     ` Qu Wenruo
2020-09-15  8:40   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 04/19] btrfs: remove the open-code to read disk-key Qu Wenruo
2020-09-15  8:36   ` Nikolay Borisov
2020-09-15  8:40   ` Johannes Thumshirn
2020-09-16 16:01   ` David Sterba
2020-09-17  8:02     ` Qu Wenruo
2020-09-17 12:37       ` David Sterba
2020-09-17 13:15         ` Qu Wenruo
2020-09-17 22:41           ` David Sterba
2020-09-17 23:26             ` Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 05/19] btrfs: make btrfs_fs_info::buffer_radix to take sector size devided values Qu Wenruo
2020-09-15  8:27   ` Johannes Thumshirn
2020-09-15 10:04     ` Qu Wenruo
2020-09-15 10:12       ` Johannes Thumshirn
2020-09-15 17:40   ` kernel test robot
2020-09-15  5:35 ` [PATCH v2 06/19] btrfs: don't allow tree block to cross page boundary for subpage support Qu Wenruo
2020-09-15  8:37   ` Nikolay Borisov
2020-09-15 10:06     ` Qu Wenruo
2020-09-15  8:44   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 07/19] btrfs: update num_extent_pages() to support subpage sized extent buffer Qu Wenruo
2020-09-15  8:42   ` Johannes Thumshirn
2020-09-15 10:07     ` Qu Wenruo
2020-09-15 10:12       ` Johannes Thumshirn
2020-09-15 10:07     ` Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 08/19] btrfs: handle sectorsize < PAGE_SIZE case for extent buffer accessors Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 09/19] btrfs: make csum_tree_block() handle sectorsize smaller than page size Qu Wenruo
2020-09-15  8:47   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 10/19] btrfs: add assert_spin_locked() for attach_extent_buffer_page() Qu Wenruo
2020-09-15  8:52   ` Johannes Thumshirn
2020-09-15  5:35 ` [PATCH v2 11/19] btrfs: extract the extent buffer verification from btree_readpage_end_io_hook() Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 12/19] btrfs: extent_io: only require sector size alignment for page read Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 13/19] btrfs: make btrfs_readpage_end_io_hook() follow sector size Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 14/19] btrfs: make btree inode io_tree has its special owner Qu Wenruo
2020-09-16  9:28   ` Johannes Thumshirn
2020-09-16 16:06   ` David Sterba
2020-09-17  0:02     ` Qu Wenruo
2020-09-17 12:50       ` David Sterba
2020-09-18  8:18         ` Qu Wenruo
2020-09-22 14:06           ` David Sterba
2020-09-22 14:14   ` David Sterba
2020-09-15  5:35 ` [PATCH v2 15/19] btrfs: don't set extent_io_tree bits for btree inode at endio time Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 16/19] btrfs: use extent_io_tree to handle subpage extent buffer allocation Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 17/19] btrfs: implement subpage metadata read and its endio function Qu Wenruo
2020-09-16  8:47   ` kernel test robot
2020-09-15  5:35 ` [PATCH v2 18/19] btrfs: implement btree_readpage() and try_release_extent_buffer() for subpage Qu Wenruo
2020-09-15  5:35 ` [PATCH v2 19/19] btrfs: allow RO mount of 4K sector size fs on 64K page system Qu Wenruo
2020-09-16  1:35 ` [PATCH v2 00/19] btrfs: add read-only support for subpage sector size Qu Wenruo
2020-09-16 16:18 ` Neal Gompa
2020-09-17  0:03   ` Qu Wenruo
2020-09-17  0:13     ` Neal Gompa
2020-09-17  0:24       ` Qu Wenruo

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