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authorOleg Nesterov <oleg@redhat.com>2009-01-06 23:40:29 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-07 00:59:09 +0100
commit901608d9045146aec6f14a7777ea4b1501c379f0 (patch)
tree0155189f48479b920855dedccba6829363376d4d /mm/highmem.c
parentmm: pagecache gfp flags fix (diff)
downloadlinux-901608d9045146aec6f14a7777ea4b1501c379f0.tar.xz
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mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting
xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses mm->hiwater_xxx directly, this leads to 2 problems: - taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any moment before the task exits, so we should check the current values of rss/vm anyway. - do_exit()->update_hiwater_xxx() calls are racy. An exiting thread can be preempted right before mm->hiwater_xxx = new_val, and another thread can use A_LOT of memory and exit in between. When the first thread resumes it can be the last thread in the thread group, in that case we report the wrong hiwater_xxx values which do not take A_LOT into account. Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change xacct_add_tsk() to use them. The first helper will also be used by rusage->ru_maxrss accounting. Kill do_exit()->update_hiwater_xxx() calls. Unless we are going to decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody can look at this mm_struct when exit_mmap() actually unmaps the memory. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Hugh Dickins <hugh@veritas.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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