Convert inode and dentry caches to per-zone shrinker API in preparation
for doing proper per-zone cache LRU lists. These two caches tend to be
the most important in the system after the pagecache lrus, so making these
per-zone will help to fix up the funny quirks in vmscan code that tries
to reconcile the whole zone-driven scanning with the global slab reclaim.
Cc: linux-mm@xxxxxxxxx
Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>
---
fs/dcache.c | 31 ++++++++++++++++++++-----------
fs/inode.c | 39 ++++++++++++++++++++++++---------------
2 files changed, 44 insertions(+), 26 deletions(-)
Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c 2010-10-19 14:35:42.000000000 +1100
+++ linux-2.6/fs/dcache.c 2010-10-19 14:36:53.000000000 +1100
@@ -534,7 +534,7 @@
*
* This function may fail to free any resources if all the dentries are in use.
*/
-static void prune_dcache(int count)
+static void prune_dcache(unsigned long count)
{
struct super_block *sb, *p = NULL;
int w_count;
@@ -887,7 +887,8 @@
EXPORT_SYMBOL(shrink_dcache_parent);
/*
- * Scan `nr' dentries and return the number which remain.
+ * shrink_dcache_memory scans and reclaims unused dentries. This function
+ * is defined according to the shrinker API described in linux/mm.h.
*
* We need to avoid reentering the filesystem if the caller is performing a
* GFP_NOFS allocation attempt. One example deadlock is:
@@ -895,22 +896,30 @@
* ext2_new_block->getblk->GFP->shrink_dcache_memory->prune_dcache->
* prune_one_dentry->dput->dentry_iput->iput->inode->i_sb->s_op->put_inode->
* ext2_discard_prealloc->ext2_free_blocks->lock_super->DEADLOCK.
- *
- * In this case we return -1 to tell the caller that we baled.
*/
-static int shrink_dcache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
+static void shrink_dcache_memory(struct shrinker *shrink,
+ struct zone *zone, unsigned long scanned,
+ unsigned long total, unsigned long global,
+ unsigned long flags, gfp_t gfp_mask)
{
- if (nr) {
- if (!(gfp_mask & __GFP_FS))
- return -1;
+ static unsigned long nr_to_scan;
+ unsigned long nr;
+
+ shrinker_add_scan(&nr_to_scan, scanned, global,
+ dentry_stat.nr_unused,
+ SHRINK_DEFAULT_SEEKS * 100 / sysctl_vfs_cache_pressure);
+ if (!(gfp_mask & __GFP_FS))
+ return;
+
+ while ((nr = shrinker_do_scan(&nr_to_scan, SHRINK_BATCH))) {
prune_dcache(nr);
+ count_vm_events(SLABS_SCANNED, nr);
+ cond_resched();
}
- return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker dcache_shrinker = {
- .shrink = shrink_dcache_memory,
- .seeks = DEFAULT_SEEKS,
+ .shrink_zone = shrink_dcache_memory,
};
/**
Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c 2010-10-19 14:35:42.000000000 +1100
+++ linux-2.6/fs/inode.c 2010-10-19 14:37:05.000000000 +1100
@@ -445,7 +445,7 @@
* If the inode has metadata buffers attached to mapping->private_list then
* try to remove them.
*/
-static void prune_icache(int nr_to_scan)
+static void prune_icache(unsigned long nr_to_scan)
{
LIST_HEAD(freeable);
int nr_pruned = 0;
@@ -503,27 +503,36 @@
* not open and the dcache references to those inodes have already been
* reclaimed.
*
- * This function is passed the number of inodes to scan, and it returns the
- * total number of remaining possibly-reclaimable inodes.
+ * This function is defined according to shrinker API described in linux/mm.h.
*/
-static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
+static void shrink_icache_memory(struct shrinker *shrink,
+ struct zone *zone, unsigned long scanned,
+ unsigned long total, unsigned long global,
+ unsigned long flags, gfp_t gfp_mask)
{
- if (nr) {
- /*
- * Nasty deadlock avoidance. We may hold various FS locks,
- * and we don't want to recurse into the FS that called us
- * in clear_inode() and friends..
- */
- if (!(gfp_mask & __GFP_FS))
- return -1;
+ static unsigned long nr_to_scan;
+ unsigned long nr;
+
+ shrinker_add_scan(&nr_to_scan, scanned, global,
+ inodes_stat.nr_unused,
+ SHRINK_DEFAULT_SEEKS * 100 / sysctl_vfs_cache_pressure);
+ /*
+ * Nasty deadlock avoidance. We may hold various FS locks,
+ * and we don't want to recurse into the FS that called us
+ * in clear_inode() and friends..
+ */
+ if (!(gfp_mask & __GFP_FS))
+ return;
+
+ while ((nr = shrinker_do_scan(&nr_to_scan, SHRINK_BATCH))) {
prune_icache(nr);
+ count_vm_events(SLABS_SCANNED, nr);
+ cond_resched();
}
- return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker icache_shrinker = {
- .shrink = shrink_icache_memory,
- .seeks = DEFAULT_SEEKS,
+ .shrink_zone = shrink_icache_memory,
};
static void __wait_on_freeing_inode(struct inode *inode);
--
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