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authorDominique Martinet <dominique.martinet@cea.fr>2018-07-30 09:14:37 +0300
committerDominique Martinet <dominique.martinet@cea.fr>2018-09-07 19:39:47 +0300
commit91a76be37ff89795526c452a6799576b03bec501 (patch)
treedc45cdba9b9b8e1b5fa3451024968e137fb23d16 /net/9p
parent523adb6cc10b48655c0abe556505240741425b49 (diff)
downloadlinux-91a76be37ff89795526c452a6799576b03bec501.tar.xz
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>
Diffstat (limited to 'net/9p')
-rw-r--r--net/9p/client.c37
1 files changed, 32 insertions, 5 deletions
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);