mirror of
https://github.com/torvalds/linux
synced 2024-09-23 04:49:22 +00:00
268720903f
Currently register_for_each_vma() is O(n ** 2) + O(n ** 3), every time find_next_vma_info() "restarts" the vma_prio_tree_foreach() loop and each iteration rechecks the whole try_list. This also means that try_list can grow "indefinitely" if register/unregister races with munmap/mmap activity even if the number of mapping is bounded at any time. With this patch register_for_each_vma() builds the list of mm/vaddr structures only once and does install_breakpoint() for each entry. We do not care about the new mappings which can be created after build_map_info() drops mapping->i_mmap_mutex, uprobe_mmap() should do its work. Note that we do not allocate map_info under i_mmap_mutex, this can deadlock with page reclaim (but see the next patch). So we use 2 lists, "curr" which we are going to return, and "prev" which holds the already allocated memory. The main loop deques the entry from "prev" (initially it is empty), and if "prev" becomes empty again it counts the number of entries we need to pre-allocate outside of i_mmap_mutex. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anton Arapov <anton@redhat.com> Link: http://lkml.kernel.org/r/20120615154333.GA9581@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|---|---|---|
| .. | ||
| callchain.c | ||
| core.c | ||
| hw_breakpoint.c | ||
| internal.h | ||
| Makefile | ||
| ring_buffer.c | ||
| uprobes.c | ||