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![]() Following the previous patch, further reduction of /proc/pid/smaps cost is possible for private writable shmem mappings with unpopulated areas where the page walk invokes the .pte_hole function. We can use radix tree iterator for each such area instead of calling find_get_entry() in a loop. This is possible at the extra maintenance cost of introducing another shmem function shmem_partial_swap_usage(). To demonstrate the diference, I have measured this on a process that creates a private writable 2GB mapping of a partially swapped out /dev/shm/file (which cannot employ the optimizations from the prvious patch) and doesn't populate it at all. I time how long does it take to cat /proc/pid/smaps of this process 100 times. Before this patch: real 0m3.831s user 0m0.180s sys 0m3.212s After this patch: real 0m1.176s user 0m0.180s sys 0m0.684s The time is similar to the case where a radix tree iterator is employed on the whole mapping. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
array.c | ||
base.c | ||
cmdline.c | ||
consoles.c | ||
cpuinfo.c | ||
devices.c | ||
fd.c | ||
fd.h | ||
generic.c | ||
inode.c | ||
internal.h | ||
interrupts.c | ||
Kconfig | ||
kcore.c | ||
kmsg.c | ||
loadavg.c | ||
Makefile | ||
meminfo.c | ||
namespaces.c | ||
nommu.c | ||
page.c | ||
proc_net.c | ||
proc_sysctl.c | ||
proc_tty.c | ||
root.c | ||
self.c | ||
softirqs.c | ||
stat.c | ||
task_mmu.c | ||
task_nommu.c | ||
thread_self.c | ||
uptime.c | ||
version.c | ||
vmcore.c |