#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/fs.h>
+#include <linux/flex_proportions.h>
+#include <linux/backing-dev-defs.h>
DECLARE_PER_CPU(int, dirty_throttle_leaks);
unsigned for_reclaim:1; /* Invoked from the page allocator */
unsigned range_cyclic:1; /* range_start is cyclic */
unsigned for_sync:1; /* sync(2) WB_SYNC_ALL writeback */
+#ifdef CONFIG_CGROUP_WRITEBACK
+ struct bdi_writeback *wb; /* wb this writeback is issued under */
+ struct inode *inode; /* inode being written out */
+
+ /* foreign inode detection, see wbc_detach_inode() */
+ int wb_id; /* current wb id */
+ int wb_lcand_id; /* last foreign candidate wb id */
+ int wb_tcand_id; /* this foreign candidate wb id */
+ size_t wb_bytes; /* bytes written by current wb */
+ size_t wb_lcand_bytes; /* bytes written by last candidate */
+ size_t wb_tcand_bytes; /* bytes written by this candidate */
+#endif
+};
+
+/*
+ * A wb_domain represents a domain that wb's (bdi_writeback's) belong to
+ * and are measured against each other in. There always is one global
+ * domain, global_wb_domain, that every wb in the system is a member of.
+ * This allows measuring the relative bandwidth of each wb to distribute
+ * dirtyable memory accordingly.
+ */
+struct wb_domain {
+ spinlock_t lock;
+
+ /*
+ * Scale the writeback cache size proportional to the relative
+ * writeout speed.
+ *
+ * We do this by keeping a floating proportion between BDIs, based
+ * on page writeback completions [end_page_writeback()]. Those
+ * devices that write out pages fastest will get the larger share,
+ * while the slower will get a smaller share.
+ *
+ * We use page writeout completions because we are interested in
+ * getting rid of dirty pages. Having them written out is the
+ * primary goal.
+ *
+ * We introduce a concept of time, a period over which we measure
+ * these events, because demand can/will vary over time. The length
+ * of this period itself is measured in page writeback completions.
+ */
+ struct fprop_global completions;
+ struct timer_list period_timer; /* timer for aging of completions */
+ unsigned long period_time;
+
+ /*
+ * The dirtyable memory and dirty threshold could be suddenly
+ * knocked down by a large amount (eg. on the startup of KVM in a
+ * swapless system). This may throw the system into deep dirty
+ * exceeded state and throttle heavy/light dirtiers alike. To
+ * retain good responsiveness, maintain global_dirty_limit for
+ * tracking slowly down to the knocked down dirty threshold.
+ *
+ * Both fields are protected by ->lock.
+ */
+ unsigned long dirty_limit_tstamp;
+ unsigned long dirty_limit;
};
+/**
+ * wb_domain_size_changed - memory available to a wb_domain has changed
+ * @dom: wb_domain of interest
+ *
+ * This function should be called when the amount of memory available to
+ * @dom has changed. It resets @dom's dirty limit parameters to prevent
+ * the past values which don't match the current configuration from skewing
+ * dirty throttling. Without this, when memory size of a wb_domain is
+ * greatly reduced, the dirty throttling logic may allow too many pages to
+ * be dirtied leading to consecutive unnecessary OOMs and may get stuck in
+ * that situation.
+ */
+static inline void wb_domain_size_changed(struct wb_domain *dom)
+{
+ spin_lock(&dom->lock);
+ dom->dirty_limit_tstamp = jiffies;
+ dom->dirty_limit = 0;
+ spin_unlock(&dom->lock);
+}
+
/*
* fs/fs-writeback.c
*/
void writeback_inodes_sb(struct super_block *, enum wb_reason reason);
void writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
enum wb_reason reason);
-int try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
-int try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
- enum wb_reason reason);
+bool try_to_writeback_inodes_sb(struct super_block *, enum wb_reason reason);
+bool try_to_writeback_inodes_sb_nr(struct super_block *, unsigned long nr,
+ enum wb_reason reason);
void sync_inodes_sb(struct super_block *);
void wakeup_flusher_threads(long nr_pages, enum wb_reason reason);
void inode_wait_for_writeback(struct inode *inode);
wait_on_bit(&inode->i_state, __I_NEW, TASK_UNINTERRUPTIBLE);
}
+#ifdef CONFIG_CGROUP_WRITEBACK
+
+#include <linux/cgroup.h>
+#include <linux/bio.h>
+
+void __inode_attach_wb(struct inode *inode, struct page *page);
+void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+ struct inode *inode)
+ __releases(&inode->i_lock);
+void wbc_detach_inode(struct writeback_control *wbc);
+void wbc_account_io(struct writeback_control *wbc, struct page *page,
+ size_t bytes);
+void cgroup_writeback_umount(void);
+
+/**
+ * inode_attach_wb - associate an inode with its wb
+ * @inode: inode of interest
+ * @page: page being dirtied (may be NULL)
+ *
+ * If @inode doesn't have its wb, associate it with the wb matching the
+ * memcg of @page or, if @page is NULL, %current. May be called w/ or w/o
+ * @inode->i_lock.
+ */
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+ if (!inode->i_wb)
+ __inode_attach_wb(inode, page);
+}
+
+/**
+ * inode_detach_wb - disassociate an inode from its wb
+ * @inode: inode of interest
+ *
+ * @inode is being freed. Detach from its wb.
+ */
+static inline void inode_detach_wb(struct inode *inode)
+{
+ if (inode->i_wb) {
+ wb_put(inode->i_wb);
+ inode->i_wb = NULL;
+ }
+}
+
+/**
+ * wbc_attach_fdatawrite_inode - associate wbc and inode for fdatawrite
+ * @wbc: writeback_control of interest
+ * @inode: target inode
+ *
+ * This function is to be used by __filemap_fdatawrite_range(), which is an
+ * alternative entry point into writeback code, and first ensures @inode is
+ * associated with a bdi_writeback and attaches it to @wbc.
+ */
+static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+ struct inode *inode)
+{
+ spin_lock(&inode->i_lock);
+ inode_attach_wb(inode, NULL);
+ wbc_attach_and_unlock_inode(wbc, inode);
+}
+
+/**
+ * wbc_init_bio - writeback specific initializtion of bio
+ * @wbc: writeback_control for the writeback in progress
+ * @bio: bio to be initialized
+ *
+ * @bio is a part of the writeback in progress controlled by @wbc. Perform
+ * writeback specific initialization. This is used to apply the cgroup
+ * writeback context.
+ */
+static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
+{
+ /*
+ * pageout() path doesn't attach @wbc to the inode being written
+ * out. This is intentional as we don't want the function to block
+ * behind a slow cgroup. Ultimately, we want pageout() to kick off
+ * regular writeback instead of writing things out itself.
+ */
+ if (wbc->wb)
+ bio_associate_blkcg(bio, wbc->wb->blkcg_css);
+}
+
+#else /* CONFIG_CGROUP_WRITEBACK */
+
+static inline void inode_attach_wb(struct inode *inode, struct page *page)
+{
+}
+
+static inline void inode_detach_wb(struct inode *inode)
+{
+}
+
+static inline void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
+ struct inode *inode)
+ __releases(&inode->i_lock)
+{
+ spin_unlock(&inode->i_lock);
+}
+
+static inline void wbc_attach_fdatawrite_inode(struct writeback_control *wbc,
+ struct inode *inode)
+{
+}
+
+static inline void wbc_detach_inode(struct writeback_control *wbc)
+{
+}
+
+static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio)
+{
+}
+
+static inline void wbc_account_io(struct writeback_control *wbc,
+ struct page *page, size_t bytes)
+{
+}
+
+static inline void cgroup_writeback_umount(void)
+{
+}
+
+#endif /* CONFIG_CGROUP_WRITEBACK */
+
/*
* mm/page-writeback.c
*/
#endif
void throttle_vm_writeout(gfp_t gfp_mask);
bool zone_dirty_ok(struct zone *zone);
+int wb_domain_init(struct wb_domain *dom, gfp_t gfp);
+#ifdef CONFIG_CGROUP_WRITEBACK
+void wb_domain_exit(struct wb_domain *dom);
+#endif
-extern unsigned long global_dirty_limit;
+extern struct wb_domain global_wb_domain;
/* These are exported to sysctl. */
extern int dirty_background_ratio;
void __user *, size_t *, loff_t *);
void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
-unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
- unsigned long dirty);
-
-void __bdi_update_bandwidth(struct backing_dev_info *bdi,
- unsigned long thresh,
- unsigned long bg_thresh,
- unsigned long dirty,
- unsigned long bdi_thresh,
- unsigned long bdi_dirty,
- unsigned long start_time);
+unsigned long wb_calc_thresh(struct bdi_writeback *wb, unsigned long thresh);
+void wb_update_bandwidth(struct bdi_writeback *wb, unsigned long start_time);
void page_writeback_init(void);
void balance_dirty_pages_ratelimited(struct address_space *mapping);
+bool wb_over_bg_thresh(struct bdi_writeback *wb);
typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
void *data);
Code Review / kvmfornfv.git / blobdiff