[ Upstream commit 91a76be37ff89795526c452a6799576b03bec501 ] Having a specific cache for the fcall allocations helps speed up end-to-end latency. The caches will automatically be merged if there are multiple caches of items with the same size so we do not need to try to share a cache between different clients of the same size. Since the msize is negotiated with the server, only allocate the cache after that negotiation has happened - previous allocations or allocations of different sizes (e.g. zero-copy fcall) are made with kmalloc directly. Some figures on two beefy VMs with Connect-IB (sriov) / trans=rdma, with ior running 32 processes in parallel doing small 32 bytes IOs: - no alloc (4.18-rc7 request cache): 65.4k req/s - non-power of two alloc, no patch: 61.6k req/s - power of two alloc, no patch: 62.2k req/s - non-power of two alloc, with patch: 64.7k req/s - power of two alloc, with patch: 65.1k req/s Link: http://lkml.kernel.org/r/1532943263-24378-2-git-send-email-asmadeus@xxxxxxxxxxxxx Signed-off-by: Dominique Martinet <dominique.martinet@xxxxxx> Acked-by: Jun Piao <piaojun@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Greg Kurz <groug@xxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- include/net/9p/9p.h | 4 ++++ include/net/9p/client.h | 1 + net/9p/client.c | 37 ++++++++++++++++++++++++++++++++----- 3 files changed, 37 insertions(+), 5 deletions(-) diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h index b8eb51a661e5..4ab293f574e0 100644 --- a/include/net/9p/9p.h +++ b/include/net/9p/9p.h @@ -336,6 +336,9 @@ enum p9_qid_t { #define P9_NOFID (u32)(~0) #define P9_MAXWELEM 16 +/* Minimal header size: size[4] type[1] tag[2] */ +#define P9_HDRSZ 7 + /* ample room for Twrite/Rread header */ #define P9_IOHDRSZ 24 @@ -558,6 +561,7 @@ struct p9_fcall { size_t offset; size_t capacity; + struct kmem_cache *cache; u8 *sdata; }; diff --git a/include/net/9p/client.h b/include/net/9p/client.h index c2671d40bb6b..735f3979d559 100644 --- a/include/net/9p/client.h +++ b/include/net/9p/client.h @@ -123,6 +123,7 @@ struct p9_client { struct p9_trans_module *trans_mod; enum p9_trans_status status; void *trans; + struct kmem_cache *fcall_cache; union { struct { diff --git a/net/9p/client.c b/net/9p/client.c index 83e39fef58e1..7ef54719c6f7 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -237,9 +237,16 @@ static int parse_opts(char *opts, struct p9_client *clnt) return ret; } -static int p9_fcall_init(struct p9_fcall *fc, int alloc_msize) +static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc, + int alloc_msize) { - fc->sdata = kmalloc(alloc_msize, GFP_NOFS); + if (likely(c->fcall_cache) && alloc_msize == c->msize) { + fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS); + fc->cache = c->fcall_cache; + } else { + fc->sdata = kmalloc(alloc_msize, GFP_NOFS); + fc->cache = NULL; + } if (!fc->sdata) return -ENOMEM; fc->capacity = alloc_msize; @@ -248,7 +255,16 @@ static int p9_fcall_init(struct p9_fcall *fc, int alloc_msize) void p9_fcall_fini(struct p9_fcall *fc) { - kfree(fc->sdata); + /* sdata can be NULL for interrupted requests in trans_rdma, + * and kmem_cache_free does not do NULL-check for us + */ + if (unlikely(!fc->sdata)) + return; + + if (fc->cache) + kmem_cache_free(fc->cache, fc->sdata); + else + kfree(fc->sdata); } EXPORT_SYMBOL(p9_fcall_fini); @@ -273,9 +289,9 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size) if (!req) return NULL; - if (p9_fcall_init(&req->tc, alloc_msize)) + if (p9_fcall_init(c, &req->tc, alloc_msize)) goto free_req; - if (p9_fcall_init(&req->rc, alloc_msize)) + if (p9_fcall_init(c, &req->rc, alloc_msize)) goto free; p9pdu_reset(&req->tc); @@ -965,6 +981,7 @@ struct p9_client *p9_client_create(const char *dev_name, char *options) clnt->trans_mod = NULL; clnt->trans = NULL; + clnt->fcall_cache = NULL; client_id = utsname()->nodename; memcpy(clnt->name, client_id, strlen(client_id) + 1); @@ -1008,6 +1025,15 @@ struct p9_client *p9_client_create(const char *dev_name, char *options) if (err) goto close_trans; + /* P9_HDRSZ + 4 is the smallest packet header we can have that is + * followed by data accessed from userspace by read + */ + clnt->fcall_cache = + kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize, + 0, 0, P9_HDRSZ + 4, + clnt->msize - (P9_HDRSZ + 4), + NULL); + return clnt; close_trans: @@ -1039,6 +1065,7 @@ void p9_client_destroy(struct p9_client *clnt) p9_tag_cleanup(clnt); + kmem_cache_destroy(clnt->fcall_cache); kfree(clnt); } EXPORT_SYMBOL(p9_client_destroy); -- 2.20.1
