From: Kent Overstreet <kent.overstreet@gmail.com>
To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
viro@zeniv.linux.org.uk, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Fixup patch for [PATCH 0/2] generic_file_buffered_read() refactoring & optimization
Date: Mon, 29 Jun 2020 20:12:33 -0400 [thread overview]
Message-ID: <20200630001233.GA39358@moria.home.lan> (raw)
In-Reply-To: <20200610001036.3904844-1-kent.overstreet@gmail.com>
Andrew - fixup patch because I got a bug report where we were trying to do an
order 7 allocation here:
-- >8 --
Subject: [PATCH] fixup! fs: generic_file_buffered_read() now uses
find_get_pages_contig
We shouldn't try to pin too many pages at once, reads can be almost
arbitrarily big.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
---
mm/filemap.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index d8bd5e9647..b3a2aad1b7 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2220,8 +2220,9 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
struct inode *inode = mapping->host;
size_t orig_count = iov_iter_count(iter);
struct page *pages_onstack[8], **pages = NULL;
- unsigned int nr_pages = ((iocb->ki_pos + iter->count + PAGE_SIZE - 1) >> PAGE_SHIFT) -
- (iocb->ki_pos >> PAGE_SHIFT);
+ unsigned int nr_pages = min_t(unsigned int, 512,
+ ((iocb->ki_pos + iter->count + PAGE_SIZE - 1) >> PAGE_SHIFT) -
+ (iocb->ki_pos >> PAGE_SHIFT));
int i, pg_nr, error = 0;
bool writably_mapped;
loff_t isize, end_offset;
--
2.27.0
prev parent reply other threads:[~2020-06-30 0:12 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 0:10 [PATCH 0/2] generic_file_buffered_read() refactoring & optimization Kent Overstreet
2020-06-10 0:10 ` [PATCH 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-10 0:10 ` [PATCH 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-10 0:47 ` Matthew Wilcox
2020-06-10 1:08 ` Kent Overstreet
2020-06-10 1:38 ` Matthew Wilcox
2020-06-10 1:46 ` Kent Overstreet
2020-06-10 1:36 ` [PATCH v2 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-10 1:36 ` [PATCH v2 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-18 1:05 ` Andrew Morton
2020-06-19 3:20 ` [PATCH v3 0/2] generic_file_buffered_read() refactoring & optimization Kent Overstreet
2020-06-19 12:59 ` Christoph Hellwig
2020-06-19 18:44 ` Kent Overstreet
2020-06-19 3:20 ` [PATCH v3 1/2] fs: Break generic_file_buffered_read up into multiple functions Kent Overstreet
2020-06-19 3:20 ` [PATCH v3 2/2] fs: generic_file_buffered_read() now uses find_get_pages_contig Kent Overstreet
2020-06-30 0:12 ` Kent Overstreet [this message]
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