From: Zhaoyang Huang <huangzhaoyang@gmail.com>
To: Roman Gushchin <klamm@yandex-team.ru>,
Andrew Morton <akpm@linux-foundation.org>,
Zhaoyang Huang <zhaoyang.huang@unisoc.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH] mm : using bdi->ra_pages instead of ra->ra_pages within readahead
Date: Thu, 13 Aug 2020 16:11:22 +0800 [thread overview]
Message-ID: <1597306282-29927-1-git-send-email-zhaoyang.huang@unisoc.com> (raw)
file->f_ra->ra_pages will remain the initialized value since it opend, which may
be NOT equal to bdi->ra_pages as the latter one is updated somehow(etc,
echo xxx > /sys/block/dm/queue/read_ahead_kb).So having readahead use
bdi->ra_pages.
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
mm/filemap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index d78f577..259dcfd 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2499,8 +2499,8 @@ static struct file *do_sync_mmap_readahead(struct vm_fault *vmf)
*/
fpin = maybe_unlock_mmap_for_io(vmf, fpin);
ra->start = max_t(long, 0, offset - ra->ra_pages / 2);
- ra->size = ra->ra_pages;
- ra->async_size = ra->ra_pages / 4;
+ ra->size = inode_to_bdi(mapping->host)->ra_pages;
+ ra->async_size = ra->size / 4;
ra_submit(ra, mapping, file);
return fpin;
}
--
1.9.1
next reply other threads:[~2020-08-13 8:11 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-13 8:11 Zhaoyang Huang [this message]
2020-08-13 11:19 ` [RFC PATCH] mm : using bdi->ra_pages instead of ra->ra_pages within readahead Matthew Wilcox
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