On Wed, Sep 05 2018, Trond Myklebust wrote:
> For the 'files' and 'flexfiles' layout types, we do not expect the reply
> to be any larger than 4k. The block and scsi layout types are a little more
> greedy, so we keep allocating the maximum response size for now.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/filelayout/filelayout.c | 1 +
> fs/nfs/flexfilelayout/flexfilelayout.c | 1 +
> fs/nfs/pnfs.c | 7 +++++++
> fs/nfs/pnfs.h | 1 +
> 4 files changed, 10 insertions(+)
>
> diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
> index d175724ff566..61f46facb39c 100644
> --- a/fs/nfs/filelayout/filelayout.c
> +++ b/fs/nfs/filelayout/filelayout.c
> @@ -1164,6 +1164,7 @@ static struct pnfs_layoutdriver_type filelayout_type = {
> .id = LAYOUT_NFSV4_1_FILES,
> .name = "LAYOUT_NFSV4_1_FILES",
> .owner = THIS_MODULE,
> + .max_layoutget_response = 4096, /* 1 page or so... */
If it is really "1 page", then surely it should be PAGE_SIZE.
But some builds have PAGE_SIZE > 4096. So if it is really "probably noy
larger than 4K", then surely the comment should say that.
Confused.
Thanks,
NeilBrown
> .alloc_layout_hdr = filelayout_alloc_layout_hdr,
> .free_layout_hdr = filelayout_free_layout_hdr,
> .alloc_lseg = filelayout_alloc_lseg,
> diff --git a/fs/nfs/flexfilelayout/flexfilelayout.c b/fs/nfs/flexfilelayout/flexfilelayout.c
> index cae43333ef16..86bcba40ca61 100644
> --- a/fs/nfs/flexfilelayout/flexfilelayout.c
> +++ b/fs/nfs/flexfilelayout/flexfilelayout.c
> @@ -2356,6 +2356,7 @@ static struct pnfs_layoutdriver_type flexfilelayout_type = {
> .name = "LAYOUT_FLEX_FILES",
> .owner = THIS_MODULE,
> .flags = PNFS_LAYOUTGET_ON_OPEN,
> + .max_layoutget_response = 4096, /* 1 page or so... */
> .set_layoutdriver = ff_layout_set_layoutdriver,
> .alloc_layout_hdr = ff_layout_alloc_layout_hdr,
> .free_layout_hdr = ff_layout_free_layout_hdr,
> diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
> index 6b5b2d36f502..c5672c02afd6 100644
> --- a/fs/nfs/pnfs.c
> +++ b/fs/nfs/pnfs.c
> @@ -991,6 +991,7 @@ pnfs_alloc_init_layoutget_args(struct inode *ino,
> gfp_t gfp_flags)
> {
> struct nfs_server *server = pnfs_find_server(ino, ctx);
> + size_t max_reply_sz = server->pnfs_curr_ld->max_layoutget_response;
> size_t max_pages = max_response_pages(server);
> struct nfs4_layoutget *lgp;
>
> @@ -1000,6 +1001,12 @@ pnfs_alloc_init_layoutget_args(struct inode *ino,
> if (lgp == NULL)
> return NULL;
>
> + if (max_reply_sz) {
> + size_t npages = (max_reply_sz + PAGE_SIZE - 1) >> PAGE_SHIFT;
> + if (npages < max_pages)
> + max_pages = npages;
> + }
> +
> lgp->args.layout.pages = nfs4_alloc_pages(max_pages, gfp_flags);
> if (!lgp->args.layout.pages) {
> kfree(lgp);
> diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
> index ece367ebde69..e2e9fcd5341d 100644
> --- a/fs/nfs/pnfs.h
> +++ b/fs/nfs/pnfs.h
> @@ -125,6 +125,7 @@ struct pnfs_layoutdriver_type {
> struct module *owner;
> unsigned flags;
> unsigned max_deviceinfo_size;
> + unsigned max_layoutget_response;
>
> int (*set_layoutdriver) (struct nfs_server *, const struct nfs_fh *);
> int (*clear_layoutdriver) (struct nfs_server *);
> --
> 2.17.1
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