Roman Gushchin a5e8809697 mm: don't miss the last page because of round-off error ... commit 68600f623d upstream. I've noticed, that dying memory cgroups are often pinned in memory by a single pagecache page. Even under moderate memory pressure they sometimes stayed in such state for a long time. That looked strange. My investigation showed that the problem is caused by applying the LRU pressure balancing math: scan = div64_u64(scan * fraction[lru], denominator), where denominator = fraction[anon] + fraction[file] + 1. Because fraction[lru] is always less than denominator, if the initial scan size is 1, the result is always 0. This means the last page is not scanned and has no chances to be reclaimed. Fix this by rounding up the result of the division. In practice this change significantly improves the speed of dying cgroups reclaim. [guro@fb.com: prevent double calculation of DIV64_U64_ROUND_UP() arguments] Link: http://lkml.kernel.org/r/20180829213311.GA13501@castle Link: http://lkml.kernel.org/r/20180827162621.30187-3-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-12-29 13:37:59 +01:00
..
acpi	ACPICA: Update version to 20180810	2018-08-14 23:49:13 +02:00
asm-generic	mm: introduce mm_[p4d|pud|pmd]_folded	2018-12-29 13:37:58 +01:00
clocksource
crypto	crypto: speck - remove Speck	2018-11-13 11:08:46 -08:00
drm	drm: Get ref on CRTC commit object when waiting for flip_done	2018-10-18 14:23:13 -04:00
dt-bindings	ARM: SoC: late updates	2018-08-25 14:12:36 -07:00
keys
kvm	KVM: arm/arm64: vgic-v3: Add core support for Group0 SGIs	2018-08-12 12:06:34 +01:00
linux	mm: don't miss the last page because of round-off error	2018-12-29 13:37:59 +01:00
math-emu
media	media: cec: fix the Signal Free Time calculation	2018-11-13 11:08:53 -08:00
memory
misc
net	xfrm_user: fix freeing of xfrm states on acquire	2018-12-29 13:37:58 +01:00
pcmcia	pcmcia: remove long deprecated pcmcia_request_exclusive_irq() function	2018-08-18 12:30:42 -07:00
ras
rdma	IB/rxe: Revise the ib_wr_opcode enum	2018-11-13 11:08:43 -08:00
scsi	SCSI misc on 20180815	2018-08-15 22:06:26 -07:00
soc	soc: fsl: qbman: add APIs to retrieve the probing status	2018-09-27 15:43:35 -05:00
sound	ALSA: pcm: Fix interval evaluation with openmin/max	2018-12-13 09:16:16 +01:00
target
trace	sched, trace: Fix prev_state output in sched_switch tracepoint	2018-12-08 12:59:06 +01:00
uapi	x86/speculation: Add prctl() control for indirect branch speculation	2018-12-05 19:32:04 +01:00
video	fbdev changes for v4.19:	2018-08-23 15:44:58 -07:00
xen	Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"	2018-12-17 09:24:39 +01:00