Commit 5515061d authored by Committed by Linus Torvalds
mm: throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is...
mm: throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage If swap is backed by network storage such as NBD, there is a risk that a large number of reclaimers can hang the system by consuming all PF_MEMALLOC reserves. To avoid these hangs, the administrator must tune min_free_kbytes in advance which is a bit fragile. This patch throttles direct reclaimers if half the PF_MEMALLOC reserves are in use. If the system is routinely getting throttled the system administrator can increase min_free_kbytes so degradation is smoother but the system will keep running. Signed-off-by: Mel Gorman <email@example.com> Cc: David Miller <firstname.lastname@example.org> Cc: Neil Brown <email@example.com> Cc: Peter Zijlstra <firstname.lastname@example.org> Cc: Mike Christie <email@example.com> Cc: Eric B Munson <firstname.lastname@example.org> Cc: Eric Dumazet <email@example.com> Cc: Sebastian Andrzej Siewior <firstname.lastname@example.org> Cc: Mel Gorman <email@example.com> Cc: Christoph Lameter <firstname.lastname@example.org> Signed-off-by: Andrew Morton <email@example.com> Signed-off-by: Linus Torvalds <firstname.lastname@example.org>
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