From: Matthew Wilcox <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com,
ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org,
Dave Chinner <dchinner@redhat.com>,
John Hubbard <jhubbard@nvidia.com>,
Christoph Hellwig <hch@lst.de>,
William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v11 02/25] mm: Return void from various readahead functions
Date: Tue, 14 Apr 2020 08:02:10 -0700 [thread overview]
Message-ID: <20200414150233.24495-3-willy@infradead.org> (raw)
In-Reply-To: <20200414150233.24495-1-willy@infradead.org>
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
ondemand_readahead has two callers, neither of which use the return value.
That means that both ra_submit and __do_page_cache_readahead() can return
void, and we don't need to worry that a present page in the readahead
window causes us to return a smaller nr_pages than we ought to have.
Similarly, no caller uses the return value from force_page_cache_readahead().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
mm/fadvise.c | 4 ----
mm/internal.h | 12 ++++++------
mm/readahead.c | 31 +++++++++++++------------------
3 files changed, 19 insertions(+), 28 deletions(-)
diff --git a/mm/fadvise.c b/mm/fadvise.c
index 3efebfb9952c..0e66f2aaeea3 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -104,10 +104,6 @@ int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
if (!nrpages)
nrpages = ~0UL;
- /*
- * Ignore return value because fadvise() shall return
- * success even if filesystem can't retrieve a hint,
- */
force_page_cache_readahead(mapping, file, start_index, nrpages);
break;
case POSIX_FADV_NOREUSE:
diff --git a/mm/internal.h b/mm/internal.h
index 25fee17c7334..f762a34b0c57 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -49,20 +49,20 @@ void unmap_page_range(struct mmu_gather *tlb,
unsigned long addr, unsigned long end,
struct zap_details *details);
-int force_page_cache_readahead(struct address_space *, struct file *,
+void force_page_cache_readahead(struct address_space *, struct file *,
pgoff_t index, unsigned long nr_to_read);
-extern unsigned int __do_page_cache_readahead(struct address_space *mapping,
- struct file *filp, pgoff_t offset, unsigned long nr_to_read,
+void __do_page_cache_readahead(struct address_space *, struct file *,
+ pgoff_t index, unsigned long nr_to_read,
unsigned long lookahead_size);
/*
* Submit IO for the read-ahead request in file_ra_state.
*/
-static inline unsigned long ra_submit(struct file_ra_state *ra,
+static inline void ra_submit(struct file_ra_state *ra,
struct address_space *mapping, struct file *filp)
{
- return __do_page_cache_readahead(mapping, filp,
- ra->start, ra->size, ra->async_size);
+ __do_page_cache_readahead(mapping, filp,
+ ra->start, ra->size, ra->async_size);
}
/**
diff --git a/mm/readahead.c b/mm/readahead.c
index 2fe72cd29b47..41a592886da7 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -149,10 +149,8 @@ static int read_pages(struct address_space *mapping, struct file *filp,
* the pages first, then submits them for I/O. This avoids the very bad
* behaviour which would occur if page allocations are causing VM writeback.
* We really don't want to intermingle reads and writes like that.
- *
- * Returns the number of pages requested, or the maximum amount of I/O allowed.
*/
-unsigned int __do_page_cache_readahead(struct address_space *mapping,
+void __do_page_cache_readahead(struct address_space *mapping,
struct file *filp, pgoff_t offset, unsigned long nr_to_read,
unsigned long lookahead_size)
{
@@ -166,7 +164,7 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping,
gfp_t gfp_mask = readahead_gfp_mask(mapping);
if (isize == 0)
- goto out;
+ return;
end_index = ((isize - 1) >> PAGE_SHIFT);
@@ -211,23 +209,21 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping,
if (nr_pages)
read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
BUG_ON(!list_empty(&page_pool));
-out:
- return nr_pages;
}
/*
* Chunk the readahead into 2 megabyte units, so that we don't pin too much
* memory at once.
*/
-int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
- pgoff_t offset, unsigned long nr_to_read)
+void force_page_cache_readahead(struct address_space *mapping,
+ struct file *filp, pgoff_t offset, unsigned long nr_to_read)
{
struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
struct file_ra_state *ra = &filp->f_ra;
unsigned long max_pages;
if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages))
- return -EINVAL;
+ return;
/*
* If the request exceeds the readahead window, allow the read to
@@ -245,7 +241,6 @@ int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
offset += this_chunk;
nr_to_read -= this_chunk;
}
- return 0;
}
/*
@@ -378,11 +373,10 @@ static int try_context_readahead(struct address_space *mapping,
/*
* A minimal readahead algorithm for trivial sequential/random reads.
*/
-static unsigned long
-ondemand_readahead(struct address_space *mapping,
- struct file_ra_state *ra, struct file *filp,
- bool hit_readahead_marker, pgoff_t offset,
- unsigned long req_size)
+static void ondemand_readahead(struct address_space *mapping,
+ struct file_ra_state *ra, struct file *filp,
+ bool hit_readahead_marker, pgoff_t offset,
+ unsigned long req_size)
{
struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
unsigned long max_pages = ra->ra_pages;
@@ -428,7 +422,7 @@ ondemand_readahead(struct address_space *mapping,
rcu_read_unlock();
if (!start || start - offset > max_pages)
- return 0;
+ return;
ra->start = start;
ra->size = start - offset; /* old async_size */
@@ -464,7 +458,8 @@ ondemand_readahead(struct address_space *mapping,
* standalone, small random read
* Read as is, and do not pollute the readahead state.
*/
- return __do_page_cache_readahead(mapping, filp, offset, req_size, 0);
+ __do_page_cache_readahead(mapping, filp, offset, req_size, 0);
+ return;
initial_readahead:
ra->start = offset;
@@ -489,7 +484,7 @@ ondemand_readahead(struct address_space *mapping,
}
}
- return ra_submit(ra, mapping, filp);
+ ra_submit(ra, mapping, filp);
}
/**
--
2.25.1
next prev parent reply other threads:[~2020-04-14 15:21 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 15:02 [PATCH v11 00/25] Change readahead API Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 01/25] mm: Move readahead prototypes from mm.h Matthew Wilcox
2020-04-15 9:10 ` Johannes Thumshirn
2020-04-14 15:02 ` Matthew Wilcox [this message]
2020-04-14 15:02 ` [PATCH v11 03/25] mm: Ignore return value of ->readpages Matthew Wilcox
2020-04-15 9:17 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 04/25] mm: Move readahead nr_pages check into read_pages Matthew Wilcox
2020-04-15 9:19 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 05/25] mm: Add new readahead_control API Matthew Wilcox
2020-04-15 1:17 ` Andrew Morton
2020-04-15 2:18 ` Matthew Wilcox
2020-04-15 4:56 ` Andrew Morton
2020-04-15 11:22 ` Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 06/25] mm: Use readahead_control to pass arguments Matthew Wilcox
2020-04-15 9:30 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 07/25] mm: Rename various 'offset' parameters to 'index' Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 08/25] mm: rename readahead loop variable to 'i' Matthew Wilcox
2020-04-15 9:31 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 09/25] mm: Remove 'page_offset' from readahead loop Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 10/25] mm: Put readahead pages in cache earlier Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 11/25] mm: Add readahead address space operation Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 12/25] mm: Move end_index check out of readahead loop Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 13/25] mm: Add page_cache_readahead_unbounded Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 14/25] mm: Document why we don't set PageReadahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 15/25] mm: Use memalloc_nofs_save in readahead path Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-06-16 22:36 ` [Cluster-devel] " Andreas Gruenbacher
2020-06-17 0:32 ` Matthew Wilcox
2020-06-17 0:57 ` Andreas Grünbacher
2020-06-17 2:21 ` Matthew Wilcox
2020-06-18 12:46 ` Andreas Gruenbacher
2020-06-18 15:03 ` Matthew Wilcox
2020-06-18 16:40 ` Andreas Gruenbacher
2020-04-14 15:02 ` [PATCH v11 17/25] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 18/25] erofs: Convert uncompressed files " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 19/25] erofs: Convert compressed " Matthew Wilcox
2020-04-21 5:42 ` Andrew Morton
2020-04-21 7:28 ` Gao Xiang
2020-04-14 15:02 ` [PATCH v11 20/25] ext4: Convert " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 21/25] ext4: Pass the inode to ext4_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 22/25] f2fs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 23/25] f2fs: Pass the inode to f2fs_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 24/25] fuse: Convert from readpages to readahead Matthew Wilcox
2020-04-20 11:14 ` Miklos Szeredi
2020-04-20 11:43 ` Matthew Wilcox
2020-04-20 11:54 ` Miklos Szeredi
2020-04-14 15:02 ` [PATCH v11 25/25] iomap: " Matthew Wilcox
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