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authorVladimir Davydov <[email protected]>2015-09-09 15:35:48 -0700
committerLinus Torvalds <[email protected]>2015-09-10 13:29:01 -0700
commitf074a8f49eb87cde95ac9d040ad5e7ea4f029738 (patch)
treec78d0a5386ee6d9db9de32c733df404e783088d5 /include/uapi/linux
parent33c3fc71c8cfa3cc3a98beaa901c069c177dc295 (diff)
proc: export idle flag via kpageflags
As noted by Minchan, a benefit of reading idle flag from /proc/kpageflags is that one can easily filter dirty and/or unevictable pages while estimating the size of unused memory. Note that idle flag read from /proc/kpageflags may be stale in case the page was accessed via a PTE, because it would be too costly to iterate over all page mappings on each /proc/kpageflags read to provide an up-to-date value. To make sure the flag is up-to-date one has to read /sys/kernel/mm/page_idle/bitmap first. Signed-off-by: Vladimir Davydov <[email protected]> Reviewed-by: Andres Lagar-Cavilla <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Raghavendra K T <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Greg Thelen <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: David Rientjes <[email protected]> Cc: Pavel Emelyanov <[email protected]> Cc: Cyrill Gorcunov <[email protected]> Cc: Jonathan Corbet <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Diffstat (limited to 'include/uapi/linux')
-rw-r--r--include/uapi/linux/kernel-page-flags.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/uapi/linux/kernel-page-flags.h b/include/uapi/linux/kernel-page-flags.h
index a6c4962e5d46..5da5f8751ce7 100644
--- a/include/uapi/linux/kernel-page-flags.h
+++ b/include/uapi/linux/kernel-page-flags.h
@@ -33,6 +33,7 @@
#define KPF_THP 22
#define KPF_BALLOON 23
#define KPF_ZERO_PAGE 24
+#define KPF_IDLE 25
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */