From: "Matthew Wilcox (Oracle)" <[email protected]> Change iomap_page from a statically sized uptodate bitmap to a dynamically allocated uptodate bitmap, allowing an arbitrarily large page.
The only remaining places where iomap assumes an order-0 page are for files with inline data, where there's no sense in allocating a larger page. Signed-off-by: Matthew Wilcox (Oracle) <[email protected]> --- fs/iomap/buffered-io.c | 119 ++++++++++++++++++++++++++--------------- include/linux/iomap.h | 2 +- include/linux/mm.h | 2 + 3 files changed, 80 insertions(+), 43 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 0e76a4b6d98a..15d844a88439 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -23,14 +23,14 @@ static struct iomap_page * iomap_page_create(struct inode *inode, struct page *page) { struct iomap_page *iop = to_iomap_page(page); + unsigned int n; if (iop || i_blocks_per_page(inode, page) <= 1) return iop; - iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL); - atomic_set(&iop->read_count, 0); - atomic_set(&iop->write_count, 0); - bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE); + n = BITS_TO_LONGS(i_blocks_per_page(inode, page)); + iop = kmalloc(struct_size(iop, uptodate, n), + GFP_NOFS | __GFP_NOFAIL | __GFP_ZERO); /* * migrate_page_move_mapping() assumes that pages with private data have @@ -61,15 +61,16 @@ iomap_page_release(struct page *page) * Calculate the range inside the page that we actually need to read. */ static void -iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop, +iomap_adjust_read_range(struct inode *inode, struct page *page, loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp) { + struct iomap_page *iop = to_iomap_page(page); loff_t orig_pos = *pos; loff_t isize = i_size_read(inode); unsigned block_bits = inode->i_blkbits; unsigned block_size = (1 << block_bits); - unsigned poff = offset_in_page(*pos); - unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length); + unsigned poff = offset_in_this_page(page, *pos); + unsigned plen = min_t(loff_t, page_size(page) - poff, length); unsigned first = poff >> block_bits; unsigned last = (poff + plen - 1) >> block_bits; @@ -107,7 +108,8 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop, * page cache for blocks that are entirely outside of i_size. */ if (orig_pos <= isize && orig_pos + length > isize) { - unsigned end = offset_in_page(isize - 1) >> block_bits; + unsigned end = offset_in_this_page(page, isize - 1) >> + block_bits; if (first <= end && last > end) plen -= (last - end) * block_size; @@ -121,19 +123,16 @@ static void iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len) { struct iomap_page *iop = to_iomap_page(page); - struct inode *inode = page->mapping->host; - unsigned first = off >> inode->i_blkbits; - unsigned last = (off + len - 1) >> inode->i_blkbits; - unsigned int i; bool uptodate = true; if (iop) { - for (i = 0; i < i_blocks_per_page(inode, page); i++) { - if (i >= first && i <= last) - set_bit(i, iop->uptodate); - else if (!test_bit(i, iop->uptodate)) - uptodate = false; - } + struct inode *inode = page->mapping->host; + unsigned first = off >> inode->i_blkbits; + unsigned count = len >> inode->i_blkbits; + + bitmap_set(iop->uptodate, first, count); + if (!bitmap_full(iop->uptodate, i_blocks_per_page(inode, page))) + uptodate = false; } if (uptodate && !PageError(page)) @@ -194,6 +193,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page, return; BUG_ON(page->index); + BUG_ON(PageCompound(page)); BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); addr = kmap_atomic(page); @@ -203,6 +203,16 @@ iomap_read_inline_data(struct inode *inode, struct page *page, SetPageUptodate(page); } +/* + * Estimate the number of vectors we need based on the current page size; + * if we're wrong we'll end up doing an overly large allocation or needing + * to do a second allocation, neither of which is a big deal. + */ +static unsigned int iomap_nr_vecs(struct page *page, loff_t length) +{ + return (length + page_size(page) - 1) >> page_shift(page); +} + static loff_t iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -222,7 +232,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, } /* zero post-eof blocks as the page may be mapped */ - iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen); + iomap_adjust_read_range(inode, page, &pos, length, &poff, &plen); if (plen == 0) goto done; @@ -258,7 +268,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) { gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL); - int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; + int nr_vecs = iomap_nr_vecs(page, length); if (ctx->bio) submit_bio(ctx->bio); @@ -293,9 +303,9 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops) unsigned poff; loff_t ret; - for (poff = 0; poff < PAGE_SIZE; poff += ret) { - ret = iomap_apply(inode, page_offset(page) + poff, - PAGE_SIZE - poff, 0, ops, &ctx, + for (poff = 0; poff < page_size(page); poff += ret) { + ret = iomap_apply(inode, file_offset_of_page(page) + poff, + page_size(page) - poff, 0, ops, &ctx, iomap_readpage_actor); if (ret <= 0) { WARN_ON_ONCE(ret == 0); @@ -328,7 +338,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, while (!list_empty(pages)) { struct page *page = lru_to_page(pages); - if (page_offset(page) >= (u64)pos + length) + if (file_offset_of_page(page) >= (u64)pos + length) break; list_del(&page->lru); @@ -342,7 +352,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, * readpages call itself as every page gets checked again once * actually needed. */ - *done += PAGE_SIZE; + *done += page_size(page); put_page(page); } @@ -355,9 +365,14 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, { struct iomap_readpage_ctx *ctx = data; loff_t done, ret; + size_t left = 0; + + if (ctx->cur_page) + left = page_size(ctx->cur_page) - + offset_in_this_page(ctx->cur_page, pos); for (done = 0; done < length; done += ret) { - if (ctx->cur_page && offset_in_page(pos + done) == 0) { + if (ctx->cur_page && left == 0) { if (!ctx->cur_page_in_bio) unlock_page(ctx->cur_page); put_page(ctx->cur_page); @@ -369,14 +384,27 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, if (!ctx->cur_page) break; ctx->cur_page_in_bio = false; + left = page_size(ctx->cur_page); } ret = iomap_readpage_actor(inode, pos + done, length - done, ctx, iomap); + left -= ret; } return done; } +/* move to fs.h? */ +static inline struct page *readahead_first_page(struct list_head *head) +{ + return list_entry(head->prev, struct page, lru); +} + +static inline struct page *readahead_last_page(struct list_head *head) +{ + return list_entry(head->next, struct page, lru); +} + int iomap_readpages(struct address_space *mapping, struct list_head *pages, unsigned nr_pages, const struct iomap_ops *ops) @@ -385,9 +413,10 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages, .pages = pages, .is_readahead = true, }; - loff_t pos = page_offset(list_entry(pages->prev, struct page, lru)); - loff_t last = page_offset(list_entry(pages->next, struct page, lru)); - loff_t length = last - pos + PAGE_SIZE, ret = 0; + loff_t pos = file_offset_of_page(readahead_first_page(pages)); + loff_t end = file_offset_of_next_page(readahead_last_page(pages)); + loff_t length = end - pos; + loff_t ret = 0; while (length > 0) { ret = iomap_apply(mapping->host, pos, length, 0, ops, @@ -410,7 +439,7 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages, } /* - * Check that we didn't lose a page due to the arcance calling + * Check that we didn't lose a page due to the arcane calling * conventions.. */ WARN_ON_ONCE(!ret && !list_empty(ctx.pages)); @@ -435,7 +464,7 @@ iomap_is_partially_uptodate(struct page *page, unsigned long from, unsigned i; /* Limit range to one page */ - len = min_t(unsigned, PAGE_SIZE - from, count); + len = min_t(unsigned, page_size(page) - from, count); /* First and last blocks in range within page */ first = from >> inode->i_blkbits; @@ -474,7 +503,7 @@ iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len) * If we are invalidating the entire page, clear the dirty state from it * and release it to avoid unnecessary buildup of the LRU. */ - if (offset == 0 && len == PAGE_SIZE) { + if (offset == 0 && len == page_size(page)) { WARN_ON_ONCE(PageWriteback(page)); cancel_dirty_page(page); iomap_page_release(page); @@ -550,18 +579,20 @@ static int __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, struct page *page, struct iomap *iomap) { - struct iomap_page *iop = iomap_page_create(inode, page); loff_t block_size = i_blocksize(inode); loff_t block_start = pos & ~(block_size - 1); loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1); - unsigned from = offset_in_page(pos), to = from + len, poff, plen; + unsigned from = offset_in_this_page(page, pos); + unsigned to = from + len; + unsigned poff, plen; int status = 0; if (PageUptodate(page)) return 0; + iomap_page_create(inode, page); do { - iomap_adjust_read_range(inode, iop, &block_start, + iomap_adjust_read_range(inode, page, &block_start, block_end - block_start, &poff, &plen); if (plen == 0) break; @@ -673,7 +704,7 @@ __iomap_write_end(struct inode *inode, loff_t pos, unsigned len, */ if (unlikely(copied < len && !PageUptodate(page))) return 0; - iomap_set_range_uptodate(page, offset_in_page(pos), len); + iomap_set_range_uptodate(page, offset_in_this_page(page, pos), len); iomap_set_page_dirty(page); return copied; } @@ -685,6 +716,7 @@ iomap_write_end_inline(struct inode *inode, struct page *page, void *addr; WARN_ON_ONCE(!PageUptodate(page)); + BUG_ON(PageCompound(page)); BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); addr = kmap_atomic(page); @@ -749,6 +781,10 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ + /* + * XXX: We don't know what size page we'll find in the + * page cache, so only copy up to a regular page boundary. + */ offset = offset_in_page(pos); bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_count(i)); @@ -1041,19 +1077,18 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || - (page_offset(page) > size)) { + (file_offset_of_page(page) > size)) { /* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; } - /* page is wholly or partially inside EOF */ - if (((page->index + 1) << PAGE_SHIFT) > size) - length = offset_in_page(size); + offset = file_offset_of_page(page); + if (size - offset < page_size(page)) + length = offset_in_this_page(page, size); else - length = PAGE_SIZE; + length = page_size(page); - offset = page_offset(page); while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_WRITE | IOMAP_FAULT, ops, page, diff --git a/include/linux/iomap.h b/include/linux/iomap.h index bc499ceae392..86be24a8259b 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -139,7 +139,7 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, struct iomap_page { atomic_t read_count; atomic_t write_count; - DECLARE_BITMAP(uptodate, PAGE_SIZE / 512); + unsigned long uptodate[]; }; static inline struct iomap_page *to_iomap_page(struct page *page) diff --git a/include/linux/mm.h b/include/linux/mm.h index 294a67b94147..04bea9f9282c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1415,6 +1415,8 @@ static inline void clear_page_pfmemalloc(struct page *page) extern void pagefault_out_of_memory(void); #define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) +#define offset_in_this_page(page, p) \ + ((unsigned long)(p) & (page_size(page) - 1)) /* * Flags passed to show_mem() and show_free_areas() to suppress output in -- 2.23.0
