[PATCH 26/32] NFS: Add a ->migratepage() aop for NFS

Trond Myklebust
2009-08-19T23:40:58Z

Make NFS a bit more friendly to NUMA and memory hot removal...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
fs/nfs/file.c | 1 +
fs/nfs/internal.h | 6 +++
fs/nfs/write.c | 91 ++++++++++++++++++++++++++++++++++++++++-------------
3 files changed, 76 insertions(+), 22 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 0506232..dfc8967 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -479,6 +479,7 @@ const struct address_space_operations nfs_file_aops = {
.invalidatepage = nfs_invalidate_page,
.releasepage = nfs_release_page,
.direct_IO = nfs_direct_IO,
+ .migratepage = nfs_migrate_page,
.launder_page = nfs_launder_page,
};

diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 7dd90a6..e2ccb4a 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -248,6 +248,12 @@ extern void nfs_read_prepare(struct rpc_task *task, void *calldata);

/* write.c */
extern void nfs_write_prepare(struct rpc_task *task, void *calldata);
+#ifdef CONFIG_MIGRATION
+extern int nfs_migrate_page(struct address_space *,
+ struct page *, struct page *);
+#else
+#define nfs_migrate_page NULL
+#endif

/* nfs4proc.c */
extern int _nfs4_call_sync(struct nfs_server *server,
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 0a0a2ff..6240e64 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -13,6 +13,7 @@
#include <linux/file.h>
#include <linux/writeback.h>
#include <linux/swap.h>
+#include <linux/migrate.h>

#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
@@ -26,6 +27,7 @@
#include "internal.h"
#include "iostat.h"
#include "nfs4_fs.h"
+#include "fscache.h"

#define NFSDBG_FACILITY NFSDBG_PAGECACHE

@@ -220,24 +222,17 @@ static void nfs_end_page_writeback(struct page *page)
clear_bdi_congested(&nfss->backing_dev_info, BLK_RW_ASYNC);
}

-/*
- * Find an associated nfs write request, and prepare to flush it out
- * May return an error if the user signalled nfs_wait_on_request().
- */
-static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
- struct page *page)
+static struct nfs_page *nfs_find_and_lock_request(struct page *page)
{
struct inode *inode = page->mapping->host;
struct nfs_page *req;
int ret;

spin_lock(&inode->i_lock);
- for(;;) {
+ for (;;) {
req = nfs_page_find_request_locked(page);
- if (req == NULL) {
- spin_unlock(&inode->i_lock);
- return 0;
- }
+ if (req == NULL)
+ break;
if (nfs_set_page_tag_locked(req))
break;
/* Note: If we hold the page lock, as is the case in nfs_writepage,
@@ -249,23 +244,40 @@ static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
ret = nfs_wait_on_request(req);
nfs_release_request(req);
if (ret != 0)
- return ret;
+ return ERR_PTR(ret);
spin_lock(&inode->i_lock);
}
- if (test_bit(PG_CLEAN, &req->wb_flags)) {
- spin_unlock(&inode->i_lock);
- BUG();
- }
- if (nfs_set_page_writeback(page) != 0) {
- spin_unlock(&inode->i_lock);
- BUG();
- }
spin_unlock(&inode->i_lock);
+ return req;
+}
+
+/*
+ * Find an associated nfs write request, and prepare to flush it out
+ * May return an error if the user signalled nfs_wait_on_request().
+ */
+static int nfs_page_async_flush(struct nfs_pageio_descriptor *pgio,
+ struct page *page)
+{
+ struct nfs_page *req;
+ int ret = 0;
+
+ req = nfs_find_and_lock_request(page);
+ if (!req)
+ goto out;
+ ret = PTR_ERR(req);
+ if (IS_ERR(req))
+ goto out;
+
+ ret = nfs_set_page_writeback(page);
+ BUG_ON(ret != 0);
+ BUG_ON(test_bit(PG_CLEAN, &req->wb_flags));
+
if (!nfs_pageio_add_request(pgio, req)) {
nfs_redirty_request(req);
- return pgio->pg_error;
+ ret = pgio->pg_error;
}
- return 0;
+out:
+ return ret;
}

static int nfs_do_writepage(struct page *page, struct writeback_control *wbc, struct nfs_pageio_descriptor *pgio)
@@ -1582,6 +1594,41 @@ int nfs_wb_page(struct inode *inode, struct page* page)
return nfs_wb_page_priority(inode, page, FLUSH_STABLE);
}

+#ifdef CONFIG_MIGRATION
+int nfs_migrate_page(struct address_space *mapping, struct page *newpage,
+ struct page *page)
+{
+ struct nfs_page *req;
+ int ret;
+
+ if (PageFsCache(page))
+ nfs_fscache_release_page(page, GFP_KERNEL);
+
+ req = nfs_find_and_lock_request(page);
+ ret = PTR_ERR(req);
+ if (IS_ERR(req))
+ goto out;
+
+ ret = migrate_page(mapping, newpage, page);
+ if (!req)
+ goto out;
+ if (ret)
+ goto out_unlock;
+ page_cache_get(newpage);
+ req->wb_page = newpage;
+ SetPagePrivate(newpage);
+ set_page_private(newpage, page_private(page));
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ page_cache_release(page);
+out_unlock:
+ nfs_clear_page_tag_locked(req);
+ nfs_release_request(req);
+out:
+ return ret;
+}
+#endif
+
int __init nfs_init_writepagecache(void)
{
nfs_wdata_cachep = kmem_cache_create("nfs_write_data",
--
1.6.0.4