From: Jan Kara Subject: Re: [PATCHv3 1/3] fs/buffer.c: allocate buffer cache with user specific flag Date: Mon, 1 Sep 2014 09:53:01 +0200 Message-ID: <20140901075301.GA32399@quack.suse.cz> References: <53FE9357.6000505@lge.com> <53FE9492.1030909@lge.com> <20140828105909.GE5961@quack.suse.cz> <5400061B.7060709@lge.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Alexander Viro , Andrew Morton , "Paul E. McKenney" , Peter Zijlstra , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Theodore Ts'o , Andreas Dilger , linux-ext4@vger.kernel.org, Minchan Kim , Joonsoo Kim , =?utf-8?B?7J206rG07Zi4?= To: Gioh Kim Return-path: Content-Disposition: inline In-Reply-To: <5400061B.7060709@lge.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri 29-08-14 13:48:27, Gioh Kim wrote: > What about below?: add gfp for __getblk_slow, change __getblk into __getblk_gfp, > getblk_unmovable and __getblk are, I think, symmetric. > > If you say OK, I'm going to send v4 with tabs ;-) Yes, this looks like what I wanted. I've just spotted two typos in comments and one function which should be inline (see below). Thanks for work! Honza > diff --git a/fs/buffer.c b/fs/buffer.c > index 8f05111..21711c78 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -993,7 +993,7 @@ init_page_buffers(struct page *page, struct block_device *bdev, > */ > static int > grow_dev_page(struct block_device *bdev, sector_t block, > - pgoff_t index, int size, int sizebits) > + pgoff_t index, int size, int sizebits, gfp_t gfp) > { > struct inode *inode = bdev->bd_inode; > struct page *page; > @@ -1002,10 +1002,10 @@ grow_dev_page(struct block_device *bdev, sector_t block, > int ret = 0; /* Will call free_more_memory() */ > gfp_t gfp_mask; > > - gfp_mask = mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS; > - gfp_mask |= __GFP_MOVABLE; > + gfp_mask = (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS) | gfp; > + > /* > - * XXX: __getblk_slow() can not really deal with failure and > + * XXX: __getblk_gfp() can not really deal with failure and You can leave __getblk_slow() here I believe. > * will endlessly loop on improvised global reclaim. Prefer > * looping in the allocator rather than here, at least that > * code knows what it's doing. > @@ -1058,7 +1058,7 @@ failed: > * that page was dirty, the buffers are set dirty also. > */ > static int > -grow_buffers(struct block_device *bdev, sector_t block, int size) > +grow_buffers(struct block_device *bdev, sector_t block, int size, gfp_t gfp) > { > pgoff_t index; > int sizebits; > @@ -1085,11 +1085,12 @@ grow_buffers(struct block_device *bdev, sector_t block, int size) > } > > /* Create a page with the proper size buffers.. */ > - return grow_dev_page(bdev, block, index, size, sizebits); > + return grow_dev_page(bdev, block, index, size, sizebits, gfp); > } > > -static struct buffer_head * > -__getblk_slow(struct block_device *bdev, sector_t block, int size) > +struct buffer_head * > +__getblk_slow(struct block_device *bdev, sector_t block, > + unsigned size, gfp_t gfp) > { > /* Size must be multiple of hard sectorsize */ > if (unlikely(size & (bdev_logical_block_size(bdev)-1) || > @@ -1111,13 +1112,14 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size) > if (bh) > return bh; > > - ret = grow_buffers(bdev, block, size); > + ret = grow_buffers(bdev, block, size, gfp); > if (ret < 0) > return NULL; > if (ret == 0) > free_more_memory(); > } > } > +EXPORT_SYMBOL(__getblk_slow); > > /* > * The relationship between dirty buffers and dirty pages: > @@ -1371,24 +1373,25 @@ __find_get_block(struct block_device *bdev, sector_t block, unsigned size) > EXPORT_SYMBOL(__find_get_block); > > /* > - * __getblk will locate (and, if necessary, create) the buffer_head > + * __getblk_gfp will locate (and, if necessary, create) the buffer_head > * which corresponds to the passed block_device, block and size. The > * returned buffer has its reference count incremented. > * > - * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() > - * attempt is failing. FIXME, perhaps? > + * __getblk()_gfp will lock up the machine if grow_dev_page's _gfp should be before () in the line above. > + * try_to_free_buffers() attempt is failing. FIXME, perhaps? > */ > struct buffer_head * > -__getblk(struct block_device *bdev, sector_t block, unsigned size) > +__getblk_gfp(struct block_device *bdev, sector_t block, > + unsigned size, gfp_t gfp) > { > struct buffer_head *bh = __find_get_block(bdev, block, size); > > might_sleep(); > if (bh == NULL) > - bh = __getblk_slow(bdev, block, size); > + bh = __getblk_slow(bdev, block, size, gfp); > return bh; > } > -EXPORT_SYMBOL(__getblk); > +EXPORT_SYMBOL(__getblk_gfp); > > /* > * Do async read-ahead on a buffer.. > @@ -1410,18 +1413,39 @@ EXPORT_SYMBOL(__breadahead); > * @size: size (in bytes) to read > * > * Reads a specified block, and returns buffer head that contains it. > + * The page cache is allocated from movable area so that it can be migrated. > * It returns NULL if the block was unreadable. > */ > struct buffer_head * > __bread(struct block_device *bdev, sector_t block, unsigned size) > { > - struct buffer_head *bh = __getblk(bdev, block, size); > + return __bread_gfp(bdev, block, size, __GFP_MOVABLE); > +} > +EXPORT_SYMBOL(__bread); This can be just inline defined in buffer_head.h. > + > +/** > + * __bread_gfp() - reads a specified block and returns the bh > + * @bdev: the block_device to read from > + * @block: number of block > + * @size: size (in bytes) to read > + * @gfp: page allocation flag > + * > + * Reads a specified block, and returns buffer head that contains it. > + * The page cache can be allocated from non-movable area > + * not to prevent page migration if you set gfp to zero. > + * It returns NULL if the block was unreadable. > + */ > +struct buffer_head * > +__bread_gfp(struct block_device *bdev, sector_t block, > + unsigned size, gfp_t gfp) > +{ > + struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp); > > if (likely(bh) && !buffer_uptodate(bh)) > bh = __bread_slow(bh); > return bh; > } > -EXPORT_SYMBOL(__bread); > +EXPORT_SYMBOL(__bread_gfp); > > /* > * invalidate_bh_lrus() is called rarely - but not only at unmount. > diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h > index 324329c..6073f5d 100644 > --- a/include/linux/buffer_head.h > +++ b/include/linux/buffer_head.h > @@ -175,12 +175,14 @@ void __wait_on_buffer(struct buffer_head *); > wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); > struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, > unsigned size); > -struct buffer_head *__getblk(struct block_device *bdev, sector_t block, > - unsigned size); > +struct buffer_head *__getblk_gfp(struct block_device *bdev, sector_t block, > + unsigned size, gfp_t gfp); > void __brelse(struct buffer_head *); > void __bforget(struct buffer_head *); > void __breadahead(struct block_device *, sector_t block, unsigned int size); > struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size); > +struct buffer_head *__bread_gfp(struct block_device *, > + sector_t block, unsigned size, gfp_t gfp); > void invalidate_bh_lrus(void); > struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); > void free_buffer_head(struct buffer_head * bh); > @@ -295,7 +297,13 @@ static inline void bforget(struct buffer_head *bh) > static inline struct buffer_head * > sb_bread(struct super_block *sb, sector_t block) > { > - return __bread(sb->s_bdev, block, sb->s_blocksize); > + return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); > +} > + > +static inline struct buffer_head * > +sb_bread_unmovable(struct super_block *sb, sector_t block) > +{ > + return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0); > } > > static inline void > @@ -307,7 +315,7 @@ sb_breadahead(struct super_block *sb, sector_t block) > static inline struct buffer_head * > sb_getblk(struct super_block *sb, sector_t block) > { > - return __getblk(sb->s_bdev, block, sb->s_blocksize); > + return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); > } > > static inline struct buffer_head * > @@ -344,6 +352,20 @@ static inline void lock_buffer(struct buffer_head *bh) > __lock_buffer(bh); > } > > +static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, > + sector_t block, > + unsigned size) > +{ > + return __getblk_gfp(bdev, block, size, 0); > +} > + > +static inline struct buffer_head *__getblk(struct block_device *bdev, > + sector_t block, > + unsigned size) > +{ > + return __getblk_gfp(bdev, block, size, __GFP_MOVABLE); > +} > + > extern int __set_page_dirty_buffers(struct page *page); > > #else /* CONFIG_BLOCK */ > -- > 1.7.9.5 > -- Jan Kara SUSE Labs, CR