The patch titled
Subject: btrfs: convert from readpages to readahead
has been added to the -mm tree. Its filename is
btrfs-convert-from-readpages-to-readahead.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/btrfs-convert-from-readpages-to-readahead.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/btrfs-convert-from-readpages-to-readahead.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: btrfs: convert from readpages to readahead
Implement the new readahead method in btrfs using the new
readahead_page_batch() function.
Link: http://lkml.kernel.org/r/20200414150233.24495-18-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: Chao Yu <yuchao0@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Cc: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Cc: Eric Biggers <ebiggers@xxxxxxxxxx>
Cc: Gao Xiang <gaoxiang25@xxxxxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/btrfs/extent_io.c | 43 +++++++++++------------------------------
fs/btrfs/extent_io.h | 3 --
fs/btrfs/inode.c | 16 ++++++---------
3 files changed, 20 insertions(+), 42 deletions(-)
--- a/fs/btrfs/extent_io.c~btrfs-convert-from-readpages-to-readahead
+++ a/fs/btrfs/extent_io.c
@@ -4367,51 +4367,32 @@ int extent_writepages(struct address_spa
return ret;
}
-int extent_readpages(struct address_space *mapping, struct list_head *pages,
- unsigned nr_pages)
+void extent_readahead(struct readahead_control *rac)
{
struct bio *bio = NULL;
unsigned long bio_flags = 0;
struct page *pagepool[16];
struct extent_map *em_cached = NULL;
- int nr = 0;
u64 prev_em_start = (u64)-1;
+ int nr;
- while (!list_empty(pages)) {
- u64 contig_end = 0;
+ while ((nr = readahead_page_batch(rac, pagepool))) {
+ u64 contig_start = page_offset(pagepool[0]);
+ u64 contig_end = page_offset(pagepool[nr - 1]) + PAGE_SIZE - 1;
- for (nr = 0; nr < ARRAY_SIZE(pagepool) && !list_empty(pages);) {
- struct page *page = lru_to_page(pages);
+ ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end);
- prefetchw(&page->flags);
- list_del(&page->lru);
- if (add_to_page_cache_lru(page, mapping, page->index,
- readahead_gfp_mask(mapping))) {
- put_page(page);
- break;
- }
-
- pagepool[nr++] = page;
- contig_end = page_offset(page) + PAGE_SIZE - 1;
- }
-
- if (nr) {
- u64 contig_start = page_offset(pagepool[0]);
-
- ASSERT(contig_start + nr * PAGE_SIZE - 1 == contig_end);
-
- contiguous_readpages(pagepool, nr, contig_start,
- contig_end, &em_cached, &bio, &bio_flags,
- &prev_em_start);
- }
+ contiguous_readpages(pagepool, nr, contig_start, contig_end,
+ &em_cached, &bio, &bio_flags, &prev_em_start);
}
if (em_cached)
free_extent_map(em_cached);
- if (bio)
- return submit_one_bio(bio, 0, bio_flags);
- return 0;
+ if (bio) {
+ if (submit_one_bio(bio, 0, bio_flags))
+ return;
+ }
}
/*
--- a/fs/btrfs/extent_io.h~btrfs-convert-from-readpages-to-readahead
+++ a/fs/btrfs/extent_io.h
@@ -198,8 +198,7 @@ int extent_writepages(struct address_spa
struct writeback_control *wbc);
int btree_write_cache_pages(struct address_space *mapping,
struct writeback_control *wbc);
-int extent_readpages(struct address_space *mapping, struct list_head *pages,
- unsigned nr_pages);
+void extent_readahead(struct readahead_control *rac);
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len);
void set_page_extent_mapped(struct page *page);
--- a/fs/btrfs/inode.c~btrfs-convert-from-readpages-to-readahead
+++ a/fs/btrfs/inode.c
@@ -4856,8 +4856,8 @@ static void evict_inode_truncate_pages(s
/*
* Keep looping until we have no more ranges in the io tree.
- * We can have ongoing bios started by readpages (called from readahead)
- * that have their endio callback (extent_io.c:end_bio_extent_readpage)
+ * We can have ongoing bios started by readahead that have
+ * their endio callback (extent_io.c:end_bio_extent_readpage)
* still in progress (unlocked the pages in the bio but did not yet
* unlocked the ranges in the io tree). Therefore this means some
* ranges can still be locked and eviction started because before
@@ -7050,11 +7050,11 @@ static int lock_extent_direct(struct ino
* for it to complete) and then invalidate the pages for
* this range (through invalidate_inode_pages2_range()),
* but that can lead us to a deadlock with a concurrent
- * call to readpages() (a buffered read or a defrag call
+ * call to readahead (a buffered read or a defrag call
* triggered a readahead) on a page lock due to an
* ordered dio extent we created before but did not have
* yet a corresponding bio submitted (whence it can not
- * complete), which makes readpages() wait for that
+ * complete), which makes readahead wait for that
* ordered extent to complete while holding a lock on
* that page.
*/
@@ -8293,11 +8293,9 @@ static int btrfs_writepages(struct addre
return extent_writepages(mapping, wbc);
}
-static int
-btrfs_readpages(struct file *file, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages)
+static void btrfs_readahead(struct readahead_control *rac)
{
- return extent_readpages(mapping, pages, nr_pages);
+ extent_readahead(rac);
}
static int __btrfs_releasepage(struct page *page, gfp_t gfp_flags)
@@ -10553,7 +10551,7 @@ static const struct address_space_operat
.readpage = btrfs_readpage,
.writepage = btrfs_writepage,
.writepages = btrfs_writepages,
- .readpages = btrfs_readpages,
+ .readahead = btrfs_readahead,
.direct_IO = btrfs_direct_IO,
.invalidatepage = btrfs_invalidatepage,
.releasepage = btrfs_releasepage,
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-move-readahead-prototypes-from-mmh.patch
mm-return-void-from-various-readahead-functions.patch
mm-ignore-return-value-of-readpages.patch
mm-move-readahead-nr_pages-check-into-read_pages.patch
mm-add-new-readahead_control-api.patch
mm-use-readahead_control-to-pass-arguments.patch
mm-rename-various-offset-parameters-to-index.patch
mm-rename-readahead-loop-variable-to-i.patch
mm-remove-page_offset-from-readahead-loop.patch
mm-put-readahead-pages-in-cache-earlier.patch
mm-add-readahead-address-space-operation.patch
mm-move-end_index-check-out-of-readahead-loop.patch
mm-add-page_cache_readahead_unbounded.patch
mm-document-why-we-dont-set-pagereadahead.patch
mm-use-memalloc_nofs_save-in-readahead-path.patch
fs-convert-mpage_readpages-to-mpage_readahead.patch
btrfs-convert-from-readpages-to-readahead.patch
erofs-convert-uncompressed-files-from-readpages-to-readahead.patch
erofs-convert-compressed-files-from-readpages-to-readahead.patch
ext4-convert-from-readpages-to-readahead.patch
ext4-pass-the-inode-to-ext4_mpage_readpages.patch
f2fs-convert-from-readpages-to-readahead.patch
f2fs-pass-the-inode-to-f2fs_mpage_readpages.patch
fuse-convert-from-readpages-to-readahead.patch
iomap-convert-from-readpages-to-readahead.patch
