https://github.com/torvalds/linux
Revision 3ad33b2436b545cbe8b28e53f3710432cad457ab authored by Lee Schermerhorn on 15 November 2007, 00:59:10 UTC, committed by Linus Torvalds on 15 November 2007, 02:45:38 UTC
We hit the BUG_ON() in mm/rmap.c:vma_address() when trying to migrate via mbind(MPOL_MF_MOVE) a non-anon region that spans multiple vmas. For anon-regions, we just fail to migrate any pages beyond the 1st vma in the range. This occurs because do_mbind() collects a list of pages to migrate by calling check_range(). check_range() walks the task's mm, spanning vmas as necessary, to collect the migratable pages into a list. Then, do_mbind() calls migrate_pages() passing the list of pages, a function to allocate new pages based on vma policy [new_vma_page()], and a pointer to the first vma of the range. For each page in the list, new_vma_page() calls page_address_in_vma() passing the page and the vma [first in range] to obtain the address to get for alloc_page_vma(). The page address is needed to get interleaving policy correct. If the pages in the list come from multiple vmas, eventually, new_page_address() will pass that page to page_address_in_vma() with the incorrect vma. For !PageAnon pages, this will result in a bug check in rmap.c:vma_address(). For anon pages, vma_address() will just return EFAULT and fail the migration. This patch modifies new_vma_page() to check the return value from page_address_in_vma(). If the return value is EFAULT, new_vma_page() searchs forward via vm_next for the vma that maps the page--i.e., that does not return EFAULT. This assumes that the pages in the list handed to migrate_pages() is in address order. This is currently case. The patch documents this assumption in a new comment block for new_vma_page(). If new_vma_page() cannot locate the vma mapping the page in a forward search in the mm, it will pass a NULL vma to alloc_page_vma(). This will result in the allocation using the task policy, if any, else system default policy. This situation is unlikely, but the patch documents this behavior with a comment. Note, this patch results in restarting from the first vma in a multi-vma range each time new_vma_page() is called. If this is not acceptable, we can make the vma argument a pointer, both in new_vma_page() and it's caller unmap_and_move() so that the value held by the loop in migrate_pages() always passes down the last vma in which a page was found. This will require changes to all new_page_t functions passed to migrate_pages(). Is this necessary? For this patch to work, we can't bug check in vma_address() for pages outside the argument vma. This patch removes the BUG_ON(). All other callers [besides new_vma_page()] already check the return status. Tested on x86_64, 4 node NUMA platform. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent e1a1c99
Tip revision: 3ad33b2436b545cbe8b28e53f3710432cad457ab authored by Lee Schermerhorn on 15 November 2007, 00:59:10 UTC
Migration: find correct vma in new_vma_page()
Migration: find correct vma in new_vma_page()
Tip revision: 3ad33b2
Makefile.clean
# ==========================================================================
# Cleaning up
# ==========================================================================
src := $(obj)
PHONY := __clean
__clean:
# Shorthand for $(Q)$(MAKE) scripts/Makefile.clean obj=dir
# Usage:
# $(Q)$(MAKE) $(clean)=dir
clean := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.clean obj
# The filename Kbuild has precedence over Makefile
kbuild-dir := $(if $(filter /%,$(src)),$(src),$(srctree)/$(src))
include $(if $(wildcard $(kbuild-dir)/Kbuild), $(kbuild-dir)/Kbuild, $(kbuild-dir)/Makefile)
# Figure out what we need to build from the various variables
# ==========================================================================
__subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y)))
subdir-y += $(__subdir-y)
__subdir-m := $(patsubst %/,%,$(filter %/, $(obj-m)))
subdir-m += $(__subdir-m)
__subdir-n := $(patsubst %/,%,$(filter %/, $(obj-n)))
subdir-n += $(__subdir-n)
__subdir- := $(patsubst %/,%,$(filter %/, $(obj-)))
subdir- += $(__subdir-)
# Subdirectories we need to descend into
subdir-ym := $(sort $(subdir-y) $(subdir-m))
subdir-ymn := $(sort $(subdir-ym) $(subdir-n) $(subdir-))
# Add subdir path
subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn))
# build a list of files to remove, usually releative to the current
# directory
__clean-files := $(extra-y) $(always) \
$(targets) $(clean-files) \
$(host-progs) \
$(hostprogs-y) $(hostprogs-m) $(hostprogs-)
# as clean-files is given relative to the current directory, this adds
# a $(obj) prefix, except for absolute paths
__clean-files := $(wildcard \
$(addprefix $(obj)/, $(filter-out /%, $(__clean-files))) \
$(filter /%, $(__clean-files)))
# as clean-dirs is given relative to the current directory, this adds
# a $(obj) prefix, except for absolute paths
__clean-dirs := $(wildcard \
$(addprefix $(obj)/, $(filter-out /%, $(clean-dirs))) \
$(filter /%, $(clean-dirs)))
# ==========================================================================
quiet_cmd_clean = CLEAN $(obj)
cmd_clean = rm -f $(__clean-files)
quiet_cmd_cleandir = CLEAN $(__clean-dirs)
cmd_cleandir = rm -rf $(__clean-dirs)
__clean: $(subdir-ymn)
ifneq ($(strip $(__clean-files)),)
+$(call cmd,clean)
endif
ifneq ($(strip $(__clean-dirs)),)
+$(call cmd,cleandir)
endif
ifneq ($(strip $(clean-rule)),)
+$(clean-rule)
endif
@:
# ===========================================================================
# Generic stuff
# ===========================================================================
# Descending
# ---------------------------------------------------------------------------
PHONY += $(subdir-ymn)
$(subdir-ymn):
$(Q)$(MAKE) $(clean)=$@
# If quiet is set, only print short version of command
cmd = @$(if $($(quiet)cmd_$(1)),echo ' $($(quiet)cmd_$(1))' &&) $(cmd_$(1))
# Declare the contents of the .PHONY variable as phony. We keep that
# information in a variable se we can use it in if_changed and friends.
.PHONY: $(PHONY)
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