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author | Jens Axboe <axboe@suse.de> | 2006-04-02 23:11:04 +0200 |
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committer | Jens Axboe <axboe@suse.de> | 2006-04-02 23:11:04 +0200 |
commit | 3e7ee3e7b36fa4e2d88d8fb0a2577be95fc4636d (patch) | |
tree | 46e972e78122f8a719dafc87572bffb25716e745 /fs | |
parent | ad8d6f0a783ffa2ff9b0cf09910b889715772201 (diff) | |
download | linux-3e7ee3e7b36fa4e2d88d8fb0a2577be95fc4636d.tar.gz linux-3e7ee3e7b36fa4e2d88d8fb0a2577be95fc4636d.tar.bz2 linux-3e7ee3e7b36fa4e2d88d8fb0a2577be95fc4636d.zip |
[PATCH] splice: fix page stealing LRU handling.
Originally from Nick Piggin, just adapted to the newer branch.
You can't check PageLRU without holding zone->lru_lock. The page
release code can get away with it only because the page refcount is 0 at
that point. Also, you can't reliably remove pages from the LRU unless
the refcount is 0. Ever.
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Jens Axboe <axboe@suse.de>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/pipe.c | 3 | ||||
-rw-r--r-- | fs/splice.c | 30 |
2 files changed, 14 insertions, 19 deletions
diff --git a/fs/pipe.c b/fs/pipe.c index 5093408746b8..795df987cd38 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -95,6 +95,8 @@ static void anon_pipe_buf_release(struct pipe_inode_info *info, struct pipe_buff { struct page *page = buf->page; + buf->flags &= ~PIPE_BUF_FLAG_STOLEN; + /* * If nobody else uses this page, and we don't already have a * temporary page, let's keep track of it as a one-deep @@ -124,6 +126,7 @@ static void anon_pipe_buf_unmap(struct pipe_inode_info *info, struct pipe_buffer static int anon_pipe_buf_steal(struct pipe_inode_info *info, struct pipe_buffer *buf) { + buf->flags |= PIPE_BUF_FLAG_STOLEN; return 0; } diff --git a/fs/splice.c b/fs/splice.c index b5fb2f3e3ac6..bfa42a277bb8 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -67,16 +67,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, if (!remove_mapping(mapping, page)) return 1; - if (PageLRU(page)) { - struct zone *zone = page_zone(page); - - spin_lock_irq(&zone->lru_lock); - BUG_ON(!PageLRU(page)); - __ClearPageLRU(page); - del_page_from_lru(zone, page); - spin_unlock_irq(&zone->lru_lock); - } - + buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; return 0; } @@ -85,6 +76,7 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info, { page_cache_release(buf->page); buf->page = NULL; + buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); } static void *page_cache_pipe_buf_map(struct file *file, @@ -414,11 +406,12 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, { struct file *file = sd->file; struct address_space *mapping = file->f_mapping; + gfp_t gfp_mask = mapping_gfp_mask(mapping); unsigned int offset; struct page *page; pgoff_t index; char *src; - int ret, stolen; + int ret; /* * after this, page will be locked and unmapped @@ -429,7 +422,6 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, index = sd->pos >> PAGE_CACHE_SHIFT; offset = sd->pos & ~PAGE_CACHE_MASK; - stolen = 0; /* * reuse buf page, if SPLICE_F_MOVE is set @@ -443,15 +435,15 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, goto find_page; page = buf->page; - stolen = 1; - if (add_to_page_cache_lru(page, mapping, index, - mapping_gfp_mask(mapping))) + if (add_to_page_cache(page, mapping, index, gfp_mask)) goto find_page; + + if (!(buf->flags & PIPE_BUF_FLAG_LRU)) + lru_cache_add(page); } else { find_page: ret = -ENOMEM; - page = find_or_create_page(mapping, index, - mapping_gfp_mask(mapping)); + page = find_or_create_page(mapping, index, gfp_mask); if (!page) goto out; @@ -494,7 +486,7 @@ find_page: } else if (ret) goto out; - if (!stolen) { + if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { char *dst = kmap_atomic(page, KM_USER0); memcpy(dst + offset, src + buf->offset, sd->len); @@ -511,7 +503,7 @@ find_page: balance_dirty_pages_ratelimited(mapping); out: - if (!stolen) { + if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { page_cache_release(page); unlock_page(page); } |