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staging: lustre: osc: add and fixup comments for LRU handling 

Add new information about the fields in struct client_obd.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5108
Reviewed-on: http://review.whamcloud.com/10458
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jinshan Xiong 2016-12-01 17:35:30 -05:00 committed by Greg Kroah-Hartman
parent 884a136940
commit bc32a0de89
2 changed files with 35 additions and 9 deletions
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27
drivers/staging/lustre/lustre/include/obd.h
View File

@ -247,15 +247,34 @@ struct client_obd {
struct obd_histogram cl_read_offset_hist;
struct obd_histogram cl_write_offset_hist;
/* lru for osc caching pages */
/* LRU for osc caching pages */
struct cl_client_cache *cl_cache;
struct list_head cl_lru_osc; /* member of cl_cache->ccc_lru */
/** member of cl_cache->ccc_lru */
struct list_head cl_lru_osc;
/** # of available LRU slots left in the per-OSC cache.
* Available LRU slots are shared by all OSCs of the same file system,
* therefore this is a pointer to cl_client_cache::ccc_lru_left.
*/
atomic_long_t *cl_lru_left;
/** # of busy LRU pages. A page is considered busy if it's in writeback
* queue, or in transfer. Busy pages can't be discarded so they are not
* in LRU cache.
*/
atomic_long_t cl_lru_busy;
/** # of LRU pages in the cache for this client_obd */
atomic_long_t cl_lru_in_list;
/** # of threads are shrinking LRU cache. To avoid contention, it's not
* allowed to have multiple threads shrinking LRU cache.
*/
atomic_t cl_lru_shrinkers;
struct list_head cl_lru_list; /* lru page list */
spinlock_t cl_lru_list_lock; /* page list protector */
/** List of LRU pages for this client_obd */
struct list_head cl_lru_list;
/** Lock for LRU page list */
spinlock_t cl_lru_list_lock;
/** # of unstable pages in this client_obd.
* An unstable page is a page state that WRITE RPC has finished but
* the transaction has NOT yet committed.
*/
atomic_long_t cl_unstable_count;
/* number of in flight destroy rpcs is limited to max_rpcs_in_flight */

17
drivers/staging/lustre/lustre/osc/osc_page.c
View File

@ -343,16 +343,17 @@ void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
* OSC to free slots voluntarily to maintain a reasonable number of free slots
* at any time.
*/
static DECLARE_WAIT_QUEUE_HEAD(osc_lru_waitq);
/* LRU pages are freed in batch mode. OSC should at least free this
* number of pages to avoid running out of LRU budget, and..
/**
* LRU pages are freed in batch mode. OSC should at least free this
* number of pages to avoid running out of LRU slots.
*/
static const int lru_shrink_min = 2 << (20 - PAGE_SHIFT); /* 2M */
/* free this number at most otherwise it will take too long time to finish. */
static const int lru_shrink_max = 8 << (20 - PAGE_SHIFT); /* 8M */
/* Check if we can free LRU slots from this OSC. If there exists LRU waiters,
/**
* Check if we can free LRU slots from this OSC. If there exists LRU waiters,
* we should free slots aggressively. In this way, slots are freed in a steady
* step to maintain fairness among OSCs.
*
@ -643,6 +644,12 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli,
return count > 0 ? count : rc;
}
/**
* Reclaim LRU pages by an IO thread. The caller wants to reclaim at least
* \@npages of LRU slots. For performance consideration, it's better to drop
* LRU pages in batch. Therefore, the actual number is adjusted at least
* max_pages_per_rpc.
*/
long osc_lru_reclaim(struct client_obd *cli)
{
struct lu_env *env;