malhuda/msm-4.14
1
0
Fork 0
mirror of https://github.com/rd-stuffs/msm-4.14.git synced 2025-02-20 11:45:48 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

mm: Increment kswapd_waiters for throttled direct reclaimers

Browse Source 
Throttled direct reclaimers will wake up kswapd and wait for kswapd to
satisfy their page allocation request, even when the failed allocation
lacks the __GFP_KSWAPD_RECLAIM flag in its gfp mask. As a result, kswapd
may think that there are no waiters and thus exit prematurely, causing
throttled direct reclaimers lacking __GFP_KSWAPD_RECLAIM to stall on
waiting for kswapd to wake them up. Incrementing the kswapd_waiters
counter when such direct reclaimers become throttled fixes the problem.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Forenche <prahul2003@gmail.com>
This commit is contained in:
Sultan Alsawaf 2021-07-16 23:35:47 -07:00 committed by Forenche
parent 4e5a138e49
commit a4c99fe0d0
No known key found for this signature in database
GPG Key ID: 1337D655BAFE85E2
1 changed files with 11 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
mm/vmscan.c
View File

@ -3003,7 +3003,7 @@ retry:
return 0;
}
static bool allow_direct_reclaim(pg_data_t *pgdat)
static bool allow_direct_reclaim(pg_data_t *pgdat, bool using_kswapd)
{
struct zone *zone;
unsigned long pfmemalloc_reserve = 0;
@ -3032,6 +3032,10 @@ static bool allow_direct_reclaim(pg_data_t *pgdat)
wmark_ok = free_pages > pfmemalloc_reserve / 2;
/* The throttled direct reclaimer is now a kswapd waiter */
if (unlikely(!using_kswapd && !wmark_ok))
atomic_long_inc(&kswapd_waiters);
/* kswapd must be awake if processes are being throttled */
if (!wmark_ok && waitqueue_active(&pgdat->kswapd_wait)) {
if (READ_ONCE(pgdat->kswapd_classzone_idx) > ZONE_NORMAL)
@ -3097,7 +3101,7 @@ static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist,
/* Throttle based on the first usable node */
pgdat = zone->zone_pgdat;
if (allow_direct_reclaim(pgdat))
if (allow_direct_reclaim(pgdat, gfp_mask & __GFP_KSWAPD_RECLAIM))
goto out;
break;
}
@ -3119,16 +3123,18 @@ static bool throttle_direct_reclaim(gfp_t gfp_mask, struct zonelist *zonelist,
*/
if (!(gfp_mask & __GFP_FS)) {
wait_event_interruptible_timeout(pgdat->pfmemalloc_wait,
allow_direct_reclaim(pgdat), HZ);
allow_direct_reclaim(pgdat, true), HZ);
goto check_pending;
}
/* Throttle until kswapd wakes the process */
wait_event_killable(zone->zone_pgdat->pfmemalloc_wait,
allow_direct_reclaim(pgdat));
allow_direct_reclaim(pgdat, true));
check_pending:
if (unlikely(!(gfp_mask & __GFP_KSWAPD_RECLAIM)))
atomic_long_dec(&kswapd_waiters);
if (fatal_signal_pending(current))
return true;
@ -3503,7 +3509,7 @@ static int balance_pgdat(pg_data_t *pgdat, int order, int classzone_idx)
* able to safely make forward progress. Wake them
*/
if (waitqueue_active(&pgdat->pfmemalloc_wait) &&
allow_direct_reclaim(pgdat))
allow_direct_reclaim(pgdat, true))
wake_up_all(&pgdat->pfmemalloc_wait);
/* Check if kswapd should be suspending */