Eric Lee / smarc-ti-linux-kernel

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Commit 7f338fe4540b1d0600b02314c7d885fd358e9eca

Authored by Mel Gorman
Committed by Linus Torvalds
1 parent 381760eadc
Exists in master and in 20 other branches dlt-processor-sdk-linux-03.00.00.04, newt-ti-linux-3.12.y, processor-sdk-linux-01.00.00, processor-sdk-linux-02.00.01, smarc-ti-linux-3.12.10, smarc-ti-linux-3.12.y, smarc-ti-linux-3.14.y, smarc-ti-linux-3.15.y, smarc-ti-lsk-linux-4.1.y, smarct3x-processor-sdk-04.01.00.06, smarct3x-processor-sdk-linux-02.00.01, smarct3x-processor-sdk-linux-03.00.00.04, smarct4x-800-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-04.01.00.06, smarct4x-processor-sdk-linux-02.00.01, smarct4x-processor-sdk-linux-03.00.00.04, ti-linux-3.12.y, ti-linux-3.14.y, ti-linux-3.15.y, ti-lsk-linux-4.1.y

nbd: set SOCK_MEMALLOC for access to PFMEMALLOC reserves 

Set SOCK_MEMALLOC on the NBD socket to allow access to PFMEMALLOC reserves
so pages backed by NBD, particularly if swap related, can be cleaned to
prevent the machine being deadlocked.  It is still possible that the
PFMEMALLOC reserves get depleted resulting in deadlock but this can be
resolved by the administrator by increasing min_free_kbytes.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 5 additions and 1 deletions Side-by-side Diff

... ... @@ -154,6 +154,7 @@
154 154 struct msghdr msg;
155 155 struct kvec iov;
156 156 sigset_t blocked, oldset;
  157 + unsigned long pflags = current->flags;
157 158  
158 159 if (unlikely(!sock)) {
159 160 dev_err(disk_to_dev(nbd->disk),
160 161  
... ... @@ -167,8 +168,9 @@
167 168 siginitsetinv(&blocked, sigmask(SIGKILL));
168 169 sigprocmask(SIG_SETMASK, &blocked, &oldset);
169 170  
  171 + current->flags |= PF_MEMALLOC;
170 172 do {
171   - sock->sk->sk_allocation = GFP_NOIO;
  173 + sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
172 174 iov.iov_base = buf;
173 175 iov.iov_len = size;
174 176 msg.msg_name = NULL;
... ... @@ -214,6 +216,7 @@
214 216 } while (size > 0);
215 217  
216 218 sigprocmask(SIG_SETMASK, &oldset, NULL);
  219 + tsk_restore_flags(current, pflags, PF_MEMALLOC);
217 220  
218 221 return result;
219 222 }
... ... @@ -405,6 +408,7 @@
405 408  
406 409 BUG_ON(nbd->magic != NBD_MAGIC);
407 410  
  411 + sk_set_memalloc(nbd->sock->sk);
408 412 nbd->pid = task_pid_nr(current);
409 413 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
410 414 if (ret) {