From: Andrew Morton <akpm@linux-foundation.org>
To: Josef Bacik <josef@toxicpanda.com>
Cc: hannes@cmpxchg.org, linux-mm@kvack.org, jack@suse.cz,
linux-fsdevel@vger.kernel.org, kernel-team@fb.com,
linux-btrfs@vger.kernel.org, Josef Bacik <jbacik@fb.com>
Subject: Re: [PATCH 01/10] remove mapping from balance_dirty_pages*()
Date: Tue, 21 Nov 2017 14:45:28 -0800 [thread overview]
Message-ID: <20171121144528.c44458f50738d73cab3aca4b@linux-foundation.org> (raw)
In-Reply-To: <1510696616-8489-1-git-send-email-josef@toxicpanda.com>
On Tue, 14 Nov 2017 16:56:47 -0500 Josef Bacik <josef@toxicpanda.com> wrote:
> From: Josef Bacik <jbacik@fb.com>
>
> The only reason we pass in the mapping is to get the inode in order to see if
> writeback cgroups is enabled, and even then it only checks the bdi and a super
> block flag. balance_dirty_pages() doesn't even use the mapping. Since
> balance_dirty_pages*() works on a bdi level, just pass in the bdi and super
> block directly so we can avoid using mapping. This will allow us to still use
> balance_dirty_pages for dirty metadata pages that are not backed by an
> address_mapping.
>
> ...
>
> @@ -71,7 +72,8 @@ static int _block2mtd_erase(struct block2mtd_dev *dev, loff_t to, size_t len)
> memset(page_address(page), 0xff, PAGE_SIZE);
> set_page_dirty(page);
> unlock_page(page);
> - balance_dirty_pages_ratelimited(mapping);
> + balance_dirty_pages_ratelimited(inode_to_bdi(inode),
> + inode->i_sb);
> break;
> }
So we do a bunch more work in each caller and we pass two args rather
than one. That doesn't make things better!
I see that this is enablement for "dirty metadata pages that are not
backed by an address_mapping" (address_space) so I look into [7/10] and
the changelog doesn't tell me much.
So color me confused. What is this patchset actually *for*? Is there
some filesystem which has non-address_space-backed metadata? Or will
there be so soon? Or what.
I think we need a [0/n] email please. One which fully describes the
intent of the patchset.
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prev parent reply other threads:[~2017-11-21 22:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-14 21:56 [PATCH 01/10] remove mapping from balance_dirty_pages*() Josef Bacik
2017-11-14 21:56 ` [PATCH 02/10] writeback: convert WB_WRITTEN/WB_DIRITED counters to bytes Josef Bacik
2017-11-16 23:45 ` Liu Bo
2017-11-14 21:56 ` [PATCH 03/10] lib: add a batch size to fprop_global Josef Bacik
2017-11-22 8:47 ` Jan Kara
2017-11-22 8:54 ` Jan Kara
2017-11-14 21:56 ` [PATCH 04/10] lib: add a __fprop_add_percpu_max Josef Bacik
2017-11-14 21:56 ` [PATCH 05/10] writeback: convert the flexible prop stuff to bytes Josef Bacik
2017-11-14 21:56 ` [PATCH 06/10] writeback: add counters for metadata usage Josef Bacik
2017-11-22 10:21 ` Jan Kara
2017-11-14 21:56 ` [PATCH 07/10] writeback: introduce super_operations->write_metadata Josef Bacik
2017-11-14 21:56 ` [PATCH 08/10] export radix_tree_iter_tag_set Josef Bacik
2017-11-14 21:56 ` [PATCH 09/10] Btrfs: kill the btree_inode Josef Bacik
2017-11-17 1:03 ` Liu Bo
2017-11-17 1:13 ` Josef Bacik
2017-11-14 21:56 ` [PATCH 10/10] btrfs: rework end io for extent buffer reads Josef Bacik
2017-11-17 1:24 ` Liu Bo
2017-11-16 23:36 ` [PATCH 01/10] remove mapping from balance_dirty_pages*() Liu Bo
2017-11-21 22:45 ` Andrew Morton [this message]
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