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author | Dominique Martinet <dominique.martinet@cea.fr> | 2018-07-30 15:14:37 +0900 |
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committer | Dominique Martinet <dominique.martinet@cea.fr> | 2018-09-08 01:39:47 +0900 |
commit | 91a76be37ff89795526c452a6799576b03bec501 (patch) | |
tree | dc45cdba9b9b8e1b5fa3451024968e137fb23d16 | |
parent | 523adb6cc10b48655c0abe556505240741425b49 (diff) | |
download | linux-91a76be37ff89795526c452a6799576b03bec501.tar.gz linux-91a76be37ff89795526c452a6799576b03bec501.tar.bz2 linux-91a76be37ff89795526c452a6799576b03bec501.zip |
9p: add a per-client fcall kmem_cache
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@codewreck.org
Signed-off-by: Dominique Martinet <dominique.martinet@cea.fr>
Acked-by: Jun Piao <piaojun@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Greg Kurz <groug@kaod.org>
-rw-r--r-- | include/net/9p/9p.h | 4 | ||||
-rw-r--r-- | include/net/9p/client.h | 1 | ||||
-rw-r--r-- | 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 e23896116d9a..beede1e1a919 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 ed78751aee7c..f3dff8758ed7 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -231,9 +231,16 @@ free_and_return: 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; @@ -242,7 +249,16 @@ 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); @@ -267,9 +283,9 @@ 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); @@ -951,6 +967,7 @@ 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); @@ -987,6 +1004,15 @@ 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: @@ -1018,6 +1044,7 @@ 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); |