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Date: Mon, 21 Mar 2016 08:28:32 -0500
From: Dave Kleikamp <dave.kleikamp@...cle.com>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Alexander Viro <viro@...iv.linux.org.uk>,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Christoph Lameter <cl@...ux.com>,
Matthew Wilcox <willy@...ux.intel.com>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org, Dave Kleikamp <shaggy@...nel.org>
Subject: Re: [PATCH 45/71] jfs: get rid of PAGE_CACHE_* and
page_cache_{get,release} macros
On 03/20/2016 01:40 PM, Kirill A. Shutemov wrote:
> PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
> with promise that one day it will be possible to implement page cache with
> bigger chunks than PAGE_SIZE.
>
> This promise never materialized. And unlikely will.
>
> We have many places where PAGE_CACHE_SIZE assumed to be equal to
> PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
> or PAGE_* constant should be used in a particular case, especially on the
> border between fs and mm.
>
> Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
> breakage to be doable.
>
> Let's stop pretending that pages in page cache are special. They are not.
>
> The changes are pretty straight-forward:
>
> - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
>
> - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
>
> - page_cache_get() -> get_page();
>
> - page_cache_release() -> put_page();
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Looks good to me. I've also verified the jfs changes in the large patch
you sent out this morning.
Acked-by: Dave Kleikamp <dave.kleikamp@...cle.com>
> Cc: Dave Kleikamp <shaggy@...nel.org>
> ---
> fs/jfs/jfs_metapage.c | 42 +++++++++++++++++++++---------------------
> fs/jfs/jfs_metapage.h | 4 ++--
> fs/jfs/super.c | 2 +-
> 3 files changed, 24 insertions(+), 24 deletions(-)
>
> diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
> index a3eb316b1ac3..b60e015cc757 100644
> --- a/fs/jfs/jfs_metapage.c
> +++ b/fs/jfs/jfs_metapage.c
> @@ -80,7 +80,7 @@ static inline void lock_metapage(struct metapage *mp)
> static struct kmem_cache *metapage_cache;
> static mempool_t *metapage_mempool;
>
> -#define MPS_PER_PAGE (PAGE_CACHE_SIZE >> L2PSIZE)
> +#define MPS_PER_PAGE (PAGE_SIZE >> L2PSIZE)
>
> #if MPS_PER_PAGE > 1
>
> @@ -316,7 +316,7 @@ static void last_write_complete(struct page *page)
> struct metapage *mp;
> unsigned int offset;
>
> - for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
> + for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
> mp = page_to_mp(page, offset);
> if (mp && test_bit(META_io, &mp->flag)) {
> if (mp->lsn)
> @@ -366,12 +366,12 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
> int bad_blocks = 0;
>
> page_start = (sector_t)page->index <<
> - (PAGE_CACHE_SHIFT - inode->i_blkbits);
> + (PAGE_SHIFT - inode->i_blkbits);
> BUG_ON(!PageLocked(page));
> BUG_ON(PageWriteback(page));
> set_page_writeback(page);
>
> - for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
> + for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
> mp = page_to_mp(page, offset);
>
> if (!mp || !test_bit(META_dirty, &mp->flag))
> @@ -416,7 +416,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
> bio = NULL;
> } else
> inc_io(page);
> - xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
> + xlen = (PAGE_SIZE - offset) >> inode->i_blkbits;
> pblock = metapage_get_blocks(inode, lblock, &xlen);
> if (!pblock) {
> printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
> @@ -485,7 +485,7 @@ static int metapage_readpage(struct file *fp, struct page *page)
> struct inode *inode = page->mapping->host;
> struct bio *bio = NULL;
> int block_offset;
> - int blocks_per_page = PAGE_CACHE_SIZE >> inode->i_blkbits;
> + int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
> sector_t page_start; /* address of page in fs blocks */
> sector_t pblock;
> int xlen;
> @@ -494,7 +494,7 @@ static int metapage_readpage(struct file *fp, struct page *page)
>
> BUG_ON(!PageLocked(page));
> page_start = (sector_t)page->index <<
> - (PAGE_CACHE_SHIFT - inode->i_blkbits);
> + (PAGE_SHIFT - inode->i_blkbits);
>
> block_offset = 0;
> while (block_offset < blocks_per_page) {
> @@ -542,7 +542,7 @@ static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
> int ret = 1;
> int offset;
>
> - for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
> + for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
> mp = page_to_mp(page, offset);
>
> if (!mp)
> @@ -568,7 +568,7 @@ static int metapage_releasepage(struct page *page, gfp_t gfp_mask)
> static void metapage_invalidatepage(struct page *page, unsigned int offset,
> unsigned int length)
> {
> - BUG_ON(offset || length < PAGE_CACHE_SIZE);
> + BUG_ON(offset || length < PAGE_SIZE);
>
> BUG_ON(PageWriteback(page));
>
> @@ -599,10 +599,10 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
> inode->i_ino, lblock, absolute);
>
> l2bsize = inode->i_blkbits;
> - l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
> + l2BlocksPerPage = PAGE_SHIFT - l2bsize;
> page_index = lblock >> l2BlocksPerPage;
> page_offset = (lblock - (page_index << l2BlocksPerPage)) << l2bsize;
> - if ((page_offset + size) > PAGE_CACHE_SIZE) {
> + if ((page_offset + size) > PAGE_SIZE) {
> jfs_err("MetaData crosses page boundary!!");
> jfs_err("lblock = %lx, size = %d", lblock, size);
> dump_stack();
> @@ -621,7 +621,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
> mapping = inode->i_mapping;
> }
>
> - if (new && (PSIZE == PAGE_CACHE_SIZE)) {
> + if (new && (PSIZE == PAGE_SIZE)) {
> page = grab_cache_page(mapping, page_index);
> if (!page) {
> jfs_err("grab_cache_page failed!");
> @@ -693,7 +693,7 @@ unlock:
> void grab_metapage(struct metapage * mp)
> {
> jfs_info("grab_metapage: mp = 0x%p", mp);
> - page_cache_get(mp->page);
> + get_page(mp->page);
> lock_page(mp->page);
> mp->count++;
> lock_metapage(mp);
> @@ -706,12 +706,12 @@ void force_metapage(struct metapage *mp)
> jfs_info("force_metapage: mp = 0x%p", mp);
> set_bit(META_forcewrite, &mp->flag);
> clear_bit(META_sync, &mp->flag);
> - page_cache_get(page);
> + get_page(page);
> lock_page(page);
> set_page_dirty(page);
> write_one_page(page, 1);
> clear_bit(META_forcewrite, &mp->flag);
> - page_cache_release(page);
> + put_page(page);
> }
>
> void hold_metapage(struct metapage *mp)
> @@ -726,7 +726,7 @@ void put_metapage(struct metapage *mp)
> unlock_page(mp->page);
> return;
> }
> - page_cache_get(mp->page);
> + get_page(mp->page);
> mp->count++;
> lock_metapage(mp);
> unlock_page(mp->page);
> @@ -746,7 +746,7 @@ void release_metapage(struct metapage * mp)
> assert(mp->count);
> if (--mp->count || mp->nohomeok) {
> unlock_page(page);
> - page_cache_release(page);
> + put_page(page);
> return;
> }
>
> @@ -764,13 +764,13 @@ void release_metapage(struct metapage * mp)
> drop_metapage(page, mp);
>
> unlock_page(page);
> - page_cache_release(page);
> + put_page(page);
> }
>
> void __invalidate_metapages(struct inode *ip, s64 addr, int len)
> {
> sector_t lblock;
> - int l2BlocksPerPage = PAGE_CACHE_SHIFT - ip->i_blkbits;
> + int l2BlocksPerPage = PAGE_SHIFT - ip->i_blkbits;
> int BlocksPerPage = 1 << l2BlocksPerPage;
> /* All callers are interested in block device's mapping */
> struct address_space *mapping =
> @@ -788,7 +788,7 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
> page = find_lock_page(mapping, lblock >> l2BlocksPerPage);
> if (!page)
> continue;
> - for (offset = 0; offset < PAGE_CACHE_SIZE; offset += PSIZE) {
> + for (offset = 0; offset < PAGE_SIZE; offset += PSIZE) {
> mp = page_to_mp(page, offset);
> if (!mp)
> continue;
> @@ -803,7 +803,7 @@ void __invalidate_metapages(struct inode *ip, s64 addr, int len)
> remove_from_logsync(mp);
> }
> unlock_page(page);
> - page_cache_release(page);
> + put_page(page);
> }
> }
>
> diff --git a/fs/jfs/jfs_metapage.h b/fs/jfs/jfs_metapage.h
> index 337e9e51ac06..a869fb4a20d6 100644
> --- a/fs/jfs/jfs_metapage.h
> +++ b/fs/jfs/jfs_metapage.h
> @@ -106,7 +106,7 @@ static inline void metapage_nohomeok(struct metapage *mp)
> lock_page(page);
> if (!mp->nohomeok++) {
> mark_metapage_dirty(mp);
> - page_cache_get(page);
> + get_page(page);
> wait_on_page_writeback(page);
> }
> unlock_page(page);
> @@ -128,7 +128,7 @@ static inline void metapage_wait_for_io(struct metapage *mp)
> static inline void _metapage_homeok(struct metapage *mp)
> {
> if (!--mp->nohomeok)
> - page_cache_release(mp->page);
> + put_page(mp->page);
> }
>
> static inline void metapage_homeok(struct metapage *mp)
> diff --git a/fs/jfs/super.c b/fs/jfs/super.c
> index 4f5d85ba8e23..78d599198bf5 100644
> --- a/fs/jfs/super.c
> +++ b/fs/jfs/super.c
> @@ -596,7 +596,7 @@ static int jfs_fill_super(struct super_block *sb, void *data, int silent)
> * Page cache is indexed by long.
> * I would use MAX_LFS_FILESIZE, but it's only half as big
> */
> - sb->s_maxbytes = min(((u64) PAGE_CACHE_SIZE << 32) - 1,
> + sb->s_maxbytes = min(((u64) PAGE_SIZE << 32) - 1,
> (u64)sb->s_maxbytes);
> #endif
> sb->s_time_gran = 1;
>
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