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| author | Chuck Lever <chuck.lever@oracle.com> | 2021-07-01 17:03:10 +0300 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2021-08-17 18:47:52 +0300 |
| commit | 2f0f88f42f2eab0421ed37d7494de9124fdf0d34 (patch) | |
| tree | f426289ca32413bb582d1b8ecb7d673d155ddc2f /net/sunrpc | |
| parent | c7e0b781b73c2e26e442ed71397cc2bc5945a732 (diff) | |
| download | linux-2f0f88f42f2eab0421ed37d7494de9124fdf0d34.tar.xz | |
SUNRPC: Add svc_rqst_replace_page() API
Replacing a page in rq_pages[] requires a get_page(), which is a
bus-locked operation, and a put_page(), which can be even more
costly.
To reduce the cost of replacing a page in rq_pages[], batch the
put_page() operations by collecting "freed" pages in a pagevec,
and then release those pages when the pagevec is full. This
pagevec is also emptied when each RPC completes.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Diffstat (limited to 'net/sunrpc')
| -rw-r--r-- | net/sunrpc/svc.c | 21 | ||||
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 3 |
2 files changed, 24 insertions, 0 deletions
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index 0de918cb3d90..d2d412d43827 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -838,6 +838,27 @@ svc_set_num_threads_sync(struct svc_serv *serv, struct svc_pool *pool, int nrser } EXPORT_SYMBOL_GPL(svc_set_num_threads_sync); +/** + * svc_rqst_replace_page - Replace one page in rq_pages[] + * @rqstp: svc_rqst with pages to replace + * @page: replacement page + * + * When replacing a page in rq_pages, batch the release of the + * replaced pages to avoid hammering the page allocator. + */ +void svc_rqst_replace_page(struct svc_rqst *rqstp, struct page *page) +{ + if (*rqstp->rq_next_page) { + if (!pagevec_space(&rqstp->rq_pvec)) + __pagevec_release(&rqstp->rq_pvec); + pagevec_add(&rqstp->rq_pvec, *rqstp->rq_next_page); + } + + get_page(page); + *(rqstp->rq_next_page++) = page; +} +EXPORT_SYMBOL_GPL(svc_rqst_replace_page); + /* * Called from a server thread as it's exiting. Caller must hold the "service * mutex" for the service. diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index d66a8e44a1ae..682058a5ec13 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -539,6 +539,7 @@ static void svc_xprt_release(struct svc_rqst *rqstp) kfree(rqstp->rq_deferred); rqstp->rq_deferred = NULL; + pagevec_release(&rqstp->rq_pvec); svc_free_res_pages(rqstp); rqstp->rq_res.page_len = 0; rqstp->rq_res.page_base = 0; @@ -664,6 +665,8 @@ static int svc_alloc_arg(struct svc_rqst *rqstp) struct xdr_buf *arg = &rqstp->rq_arg; unsigned long pages, filled; + pagevec_init(&rqstp->rq_pvec); + pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT; if (pages > RPCSVC_MAXPAGES) { pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n", |