From: NeilBrown <neilb@suse.de>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna.schumaker@netapp.com>,
Chuck Lever <chuck.lever@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mark Hemment <markhemm@googlemail.com>,
Christoph Hellwig <hch@infradead.org>,
David Howells <dhowells@redhat.com>
Cc: linux-nfs@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 12/21] SUNRPC/call_alloc: async tasks mustn't block waiting for memory
Date: Mon, 07 Feb 2022 15:46:01 +1100 [thread overview]
Message-ID: <164420916119.29374.4983888648335050333.stgit@noble.brown> (raw)
In-Reply-To: <164420889455.29374.17958998143835612560.stgit@noble.brown>
When memory is short, new worker threads cannot be created and we depend
on the minimum one rpciod thread to be able to handle everything.
So it must not block waiting for memory.
mempools are particularly a problem as memory can only be released back
to the mempool by an async rpc task running. If all available
workqueue threads are waiting on the mempool, no thread is available to
return anything.
rpc_malloc() can block, and this might cause deadlocks.
So check RPC_IS_ASYNC(), rather than RPC_IS_SWAPPER() to determine if
blocking is acceptable.
Signed-off-by: NeilBrown <neilb@suse.de>
---
net/sunrpc/sched.c | 4 +++-
net/sunrpc/xprtrdma/transport.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index e2c835482791..d5b6e897f5a5 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -1023,8 +1023,10 @@ int rpc_malloc(struct rpc_task *task)
struct rpc_buffer *buf;
gfp_t gfp = GFP_NOFS;
+ if (RPC_IS_ASYNC(task))
+ gfp = GFP_NOWAIT | __GFP_NOWARN;
if (RPC_IS_SWAPPER(task))
- gfp = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
+ gfp |= __GFP_MEMALLOC;
size += sizeof(struct rpc_buffer);
if (size <= RPC_BUFFER_MAXSIZE)
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 42e375dbdadb..5714bf880e95 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -570,8 +570,10 @@ xprt_rdma_allocate(struct rpc_task *task)
gfp_t flags;
flags = RPCRDMA_DEF_GFP;
+ if (RPC_IS_ASYNC(task))
+ flags = GFP_NOWAIT | __GFP_NOWARN;
if (RPC_IS_SWAPPER(task))
- flags = __GFP_MEMALLOC | GFP_NOWAIT | __GFP_NOWARN;
+ flags |= __GFP_MEMALLOC;
if (!rpcrdma_check_regbuf(r_xprt, req->rl_sendbuf, rqst->rq_callsize,
flags))
next prev parent reply other threads:[~2022-02-07 4:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-07 4:46 [PATCH 00/21 V4] Repair SWAP-over_NFS NeilBrown
2022-02-07 4:46 ` [PATCH 03/21] MM: move responsibility for setting SWP_FS_OPS to ->swap_activate NeilBrown
2022-02-07 4:46 ` [PATCH 07/21] DOC: update documentation for swap_activate and swap_rw NeilBrown
2022-02-07 4:46 ` [PATCH 18/21] NFSv4: keep state manager thread active if swap is enabled NeilBrown
2022-02-07 4:46 ` [PATCH 16/21] NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS NeilBrown
2022-02-07 4:46 ` [PATCH 10/21] VFS: Add FMODE_CAN_ODIRECT file flag NeilBrown
2022-02-07 4:46 ` [PATCH 06/21] MM: perform async writes to SWP_FS_OPS swap-space using ->swap_rw NeilBrown
2022-02-07 4:46 ` [PATCH 01/21] MM: create new mm/swap.h header file NeilBrown
2022-02-10 3:24 ` [PATCH 01/21 - revised] " NeilBrown
2022-02-10 15:19 ` [PATCH 01/21] " Geert Uytterhoeven
2022-02-14 23:50 ` NeilBrown
2022-02-07 4:46 ` [PATCH 09/21] MM: submit multipage write for SWP_FS_OPS swap-space NeilBrown
2022-02-07 8:40 ` Christoph Hellwig
2022-02-07 4:46 ` [PATCH 13/21] SUNRPC/auth: async tasks mustn't block waiting for memory NeilBrown
2022-02-07 4:46 ` [PATCH 02/21] MM: drop swap_set_page_dirty NeilBrown
2022-02-07 4:46 ` [PATCH 04/21] MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space NeilBrown
2022-02-07 4:46 ` [PATCH 14/21] SUNRPC/xprt: async tasks mustn't block waiting for memory NeilBrown
2022-02-07 4:46 ` [PATCH 21/21] NFS: swap-out must always use STABLE writes NeilBrown
2022-02-07 4:46 ` [PATCH 11/21] NFS: remove IS_SWAPFILE hack NeilBrown
2022-02-07 4:46 ` [PATCH 05/21] MM: introduce ->swap_rw and use it for reads from SWP_FS_OPS swap-space NeilBrown
2022-02-07 4:46 ` [PATCH 08/21] MM: submit multipage reads for " NeilBrown
2022-02-07 4:46 ` [PATCH 20/21] NFS: swap IO handling is slightly different for O_DIRECT IO NeilBrown
2022-02-07 4:46 ` [PATCH 17/21] SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NeilBrown
2022-02-07 15:53 ` Chuck Lever III
2022-02-07 4:46 ` NeilBrown [this message]
2022-02-07 4:46 ` [PATCH 15/21] SUNRPC: remove scheduling boost for "SWAPPER" tasks NeilBrown
2022-02-07 4:46 ` [PATCH 19/21] NFS: rename nfs_direct_IO and use as ->swap_rw NeilBrown
2022-02-10 15:22 ` [PATCH 00/21 V4] Repair SWAP-over_NFS Geert Uytterhoeven
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