Eric Lee / linux-smarc-t335x-v3.2

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Commit 073e587ec2cc377867e53d8b8959738a8e16cff6

Authored by KAMEZAWA Hiroyuki
Committed by Linus Torvalds
1 parent 47c59803be
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

memcg: move charge swapin under lock 

While page-cache's charge/uncharge is done under page_lock(), swap-cache
isn't.  (anonymous page is charged when it's newly allocated.)

This patch moves do_swap_page()'s charge() call under lock.  I don't see
any bad problem *now* but this fix will be good for future for avoiding
unnecessary racy state.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 6 additions and 5 deletions Side-by-side Diff

... ... @@ -2326,15 +2326,16 @@
2326 2326 count_vm_event(PGMAJFAULT);
2327 2327 }
2328 2328  
  2329 + mark_page_accessed(page);
  2330 +
  2331 + lock_page(page);
  2332 + delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
  2333 +
2329 2334 if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
2330   - delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2331 2335 ret = VM_FAULT_OOM;
  2336 + unlock_page(page);
2332 2337 goto out;
2333 2338 }
2334   -
2335   - mark_page_accessed(page);
2336   - lock_page(page);
2337   - delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2338 2339  
2339 2340 /*
2340 2341 * Back out if somebody else already faulted in this pte.