From: trondmy@kernel.org
To: linux-nfs@vger.kernel.org
Subject: [PATCH v10 08/26] NFS: Don't re-read the entire page cache to find the next cookie
Date: Sun, 13 Mar 2022 13:05:39 -0400 [thread overview]
Message-ID: <20220313170557.5940-9-trondmy@kernel.org> (raw)
In-Reply-To: <20220313170557.5940-8-trondmy@kernel.org>
From: Trond Myklebust <trond.myklebust@hammerspace.com>
If the page cache entry that was last read gets invalidated for some
reason, then make sure we can re-create it on the next call to readdir.
This, combined with the cache page validation, allows us to reuse the
cached value of page-index on successive calls to nfs_readdir.
Credit is due to Benjamin Coddington for showing that the concept works,
and that it allows for improved cache sharing between processes even in
the case where pages are lost due to LRU or active invalidation.
Suggested-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
fs/nfs/dir.c | 10 +++++++---
include/linux/nfs_fs.h | 1 +
2 files changed, 8 insertions(+), 3 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index a1767f755460..93f70698e401 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1120,6 +1120,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
desc->dup_cookie = dir_ctx->dup_cookie;
desc->duped = dir_ctx->duped;
page_index = dir_ctx->page_index;
+ desc->page_index = page_index;
+ desc->last_cookie = dir_ctx->last_cookie;
desc->attr_gencount = dir_ctx->attr_gencount;
desc->eof = dir_ctx->eof;
memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));
@@ -1168,6 +1170,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
spin_lock(&file->f_lock);
dir_ctx->dir_cookie = desc->dir_cookie;
dir_ctx->dup_cookie = desc->dup_cookie;
+ dir_ctx->last_cookie = desc->last_cookie;
dir_ctx->duped = desc->duped;
dir_ctx->attr_gencount = desc->attr_gencount;
dir_ctx->page_index = desc->page_index;
@@ -1209,10 +1212,11 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
}
if (offset != filp->f_pos) {
filp->f_pos = offset;
- if (nfs_readdir_use_cookie(filp))
- dir_ctx->dir_cookie = offset;
- else
+ if (!nfs_readdir_use_cookie(filp)) {
dir_ctx->dir_cookie = 0;
+ dir_ctx->page_index = 0;
+ } else
+ dir_ctx->dir_cookie = offset;
if (offset == 0)
memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf));
dir_ctx->duped = 0;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 6e10725887d1..1c533f2c1f36 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -105,6 +105,7 @@ struct nfs_open_dir_context {
__be32 verf[NFS_DIR_VERIFIER_SIZE];
__u64 dir_cookie;
__u64 dup_cookie;
+ __u64 last_cookie;
pgoff_t page_index;
signed char duped;
bool eof;
--
2.35.1
next prev parent reply other threads:[~2022-03-13 17:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-13 17:05 [PATCH v10 00/26] Readdir improvements trondmy
2022-03-13 17:05 ` [PATCH v10 01/26] NFS: Return valid errors from nfs2/3_decode_dirent() trondmy
2022-03-13 17:05 ` [PATCH v10 02/26] NFS: constify nfs_server_capable() and nfs_have_writebacks() trondmy
2022-03-13 17:05 ` [PATCH v10 03/26] NFS: Trace lookup revalidation failure trondmy
2022-03-13 17:05 ` [PATCH v10 04/26] NFS: Initialise the readdir verifier as best we can in nfs_opendir() trondmy
2022-03-13 17:05 ` [PATCH v10 05/26] NFS: Use kzalloc() to avoid initialising the nfs_open_dir_context trondmy
2022-03-13 17:05 ` [PATCH v10 06/26] NFS: Calculate page offsets algorithmically trondmy
2022-03-13 17:05 ` [PATCH v10 07/26] NFS: Store the change attribute in the directory page cache trondmy
2022-03-13 17:05 ` trondmy [this message]
2022-03-13 17:05 ` [PATCH v10 09/26] NFS: Don't advance the page pointer unless the page is full trondmy
2022-03-13 17:05 ` [PATCH v10 10/26] NFS: Adjust the amount of readahead performed by NFS readdir trondmy
2022-03-13 17:05 ` [PATCH v10 11/26] NFS: If the cookie verifier changes, we must invalidate the page cache trondmy
2022-03-13 17:05 ` [PATCH v10 12/26] NFS: Simplify nfs_readdir_xdr_to_array() trondmy
2022-03-13 17:05 ` [PATCH v10 13/26] NFS: Reduce use of uncached readdir trondmy
2022-03-13 17:05 ` [PATCH v10 14/26] NFS: Improve heuristic for readdirplus trondmy
2022-03-13 17:05 ` [PATCH v10 15/26] NFS: Don't ask for readdirplus unless it can help nfs_getattr() trondmy
2022-03-13 17:05 ` [PATCH v10 16/26] NFSv4: Ask for a full XDR buffer of readdir goodness trondmy
2022-03-13 17:05 ` [PATCH v10 17/26] NFS: Readdirplus can't help lookup for case insensitive filesystems trondmy
2022-03-13 17:05 ` [PATCH v10 18/26] NFS: Don't request readdirplus when revalidation was forced trondmy
2022-03-13 17:05 ` [PATCH v10 19/26] NFS: Add basic readdir tracing trondmy
2022-03-13 17:05 ` [PATCH v10 20/26] NFS: Trace effects of readdirplus on the dcache trondmy
2022-03-13 17:05 ` [PATCH v10 21/26] NFS: Trace effects of the readdirplus heuristic trondmy
2022-03-13 17:05 ` [PATCH v10 22/26] NFS: Clean up page array initialisation/free trondmy
2022-03-13 17:05 ` [PATCH v10 23/26] NFS: Convert readdir page cache to use a cookie based index trondmy
2022-03-13 17:05 ` [PATCH v10 24/26] NFS: Fix up forced readdirplus trondmy
2022-03-13 17:05 ` [PATCH v10 25/26] NFS: Optimise away the previous cookie field trondmy
2022-03-13 17:05 ` [PATCH v10 26/26] NFS: Cache all entries in the readdirplus reply trondmy
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