linux-toradex.git/mm/internal.h, branch v5.12

mm/gup: check page posion status for coredump.

2021-04-09T21:54:23+00:00

When we do coredump for user process signal, this may be an SIGBUS signal
with BUS_MCEERR_AR or BUS_MCEERR_AO code, which means this signal is
resulted from ECC memory fail like SRAR or SRAO, we expect the memory
recovery work is finished correctly, then the get_dump_page() will not
return the error page as its process pte is set invalid by
memory_failure().

But memory_failure() may fail, and the process's related pte may not be
correctly set invalid, for current code, we will return the poison page,
get it dumped, and then lead to system panic as its in kernel code.

So check the poison status in get_dump_page(), and if TRUE, return NULL.

There maybe other scenario that is also better to check the posion status
and not to panic, so make a wrapper for this check, Thanks to David's
suggestion().

[akpm@linux-foundation.org: s/0/false/]
[yaoaili@kingsoft.com: is_page_poisoned() arg cannot be null, per Matthew]

Link: https://lkml.kernel.org/r/20210322115233.05e4e82a@alex-virtual-machine
Link: https://lkml.kernel.org/r/20210319104437.6f30e80d@alex-virtual-machine
Signed-off-by: Aili Yao 
Cc: David Hildenbrand 
Cc: Matthew Wilcox 
Cc: Naoya Horiguchi 
Cc: Oscar Salvador 
Cc: Mike Kravetz 
Cc: Aili Yao 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: introduce page_needs_cow_for_dma() for deciding whether cow

2021-03-13T19:27:30+00:00

We've got quite a few places (pte, pmd, pud) that explicitly checked
against whether we should break the cow right now during fork().  It's
easier to provide a helper, especially before we work the same thing on
hugetlbfs.

Since we'll reference is_cow_mapping() in mm.h, move it there too.
Actually it suites mm.h more since internal.h is mm/ only, but mm.h is
exported to the whole kernel.  With that we should expect another patch to
use is_cow_mapping() whenever we can across the kernel since we do use it
quite a lot but it's always done with raw code against VM_* flags.

Link: https://lkml.kernel.org/r/20210217233547.93892-4-peterx@redhat.com
Signed-off-by: Peter Xu 
Reviewed-by: Jason Gunthorpe 
Cc: Alexey Dobriyan 
Cc: Andrea Arcangeli 
Cc: Christoph Hellwig 
Cc: Daniel Vetter 
Cc: David Airlie 
Cc: David Gibson 
Cc: Gal Pressman 
Cc: Jan Kara 
Cc: Jann Horn 
Cc: Kirill Shutemov 
Cc: Kirill Tkhai 
Cc: Matthew Wilcox 
Cc: Miaohe Lin 
Cc: Mike Kravetz 
Cc: Mike Rapoport 
Cc: Roland Scheidegger 
Cc: VMware Graphics 
Cc: Wei Zhang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add and use find_lock_entries

2021-02-26T17:40:59+00:00

We have three functions (shmem_undo_range(), truncate_inode_pages_range()
and invalidate_mapping_pages()) which want exactly this function, so add
it to filemap.c.  Before this patch, shmem_undo_range() would split any
compound page which overlaps either end of the range being punched in both
the first and second loops through the address space.  After this patch,
that functionality is left for the second loop, which is arguably more
appropriate since the first loop is supposed to run through all the pages
quickly, and splitting a page can sleep.

[willy@infradead.org: add assertion]
  Link: https://lkml.kernel.org/r/20201124041507.28996-3-willy@infradead.org

Link: https://lkml.kernel.org/r/20201112212641.27837-10-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Jan Kara 
Reviewed-by: William Kucharski 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add FGP_ENTRY

2021-02-26T17:40:59+00:00

The functionality of find_lock_entry() and find_get_entry() can be
provided by pagecache_get_page(), which lets us delete find_lock_entry()
and make find_get_entry() static.

Link: https://lkml.kernel.org/r/20201112212641.27837-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: Christoph Hellwig 
Cc: Dave Chinner 
Cc: Hugh Dickins 
Cc: Jan Kara 
Cc: Johannes Weiner 
Cc: Kirill A. Shutemov 
Cc: William Kucharski 
Cc: Yang Shi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm, page_alloc: disable pcplists during memory offline

2020-12-15T20:13:43+00:00

Memory offlining relies on page isolation to guarantee a forward progress
because pages cannot be reused while they are isolated.  But the page
isolation itself doesn't prevent from races while freed pages are stored
on pcp lists and thus can be reused.  This can be worked around by
repeated draining of pcplists, as done by commit 968318261221
("mm/memory_hotplug: drain per-cpu pages again during memory offline").

David and Michal would prefer that this race was closed in a way that
callers of page isolation who need stronger guarantees don't need to
repeatedly drain.  David suggested disabling pcplists usage completely
during page isolation, instead of repeatedly draining them.

To achieve this without adding special cases in alloc/free fastpath, we
can use the same approach as boot pagesets - when pcp->high is 0, any
pcplist addition will be immediately flushed.

The race can thus be closed by setting pcp->high to 0 and draining
pcplists once, before calling start_isolate_page_range().  The draining
will serialize after processes that already disabled interrupts and read
the old value of pcp->high in free_unref_page_commit(), and processes that
have not yet disabled interrupts, will observe pcp->high == 0 when they
are rescheduled, and skip pcplists.  This guarantees no stray pages on
pcplists in zones where isolation happens.

This patch thus adds zone_pcp_disable() and zone_pcp_enable() functions
that page isolation users can call before start_isolate_page_range() and
after unisolating (or offlining) the isolated pages.

Also, drain_all_pages() is optimized to only execute on cpus where
pcplists are not empty.  The check can however race with a free to pcplist
that has not yet increased the pcp->count from 0 to 1.  Thus make the
drain optionally skip the racy check and drain on all cpus, and use this
option in zone_pcp_disable().

As we have to avoid external updates to high and batch while pcplists are
disabled, we take pcp_batch_high_lock in zone_pcp_disable() and release it
in zone_pcp_enable().  This also synchronizes multiple users of
zone_pcp_disable()/enable().

Currently the only user of this functionality is offline_pages().

[vbabka@suse.cz: add comment, per David]
  Link: https://lkml.kernel.org/r/527480ef-ed72-e1c1-52a0-1c5b0113df45@suse.cz

Link: https://lkml.kernel.org/r/20201111092812.11329-8-vbabka@suse.cz
Signed-off-by: Vlastimil Babka 
Suggested-by: David Hildenbrand 
Suggested-by: Michal Hocko 
Reviewed-by: Oscar Salvador 
Reviewed-by: David Hildenbrand 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move free_unref_page to mm/internal.h

2020-12-15T20:13:41+00:00

Code outside mm/ should not be calling free_unref_page().  Also move
free_unref_page_list().

Link: https://lkml.kernel.org/r/20201125034655.27687-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) 
Reviewed-by: David Hildenbrand 
Reviewed-by: Mike Rapoport 
Acked-by: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: rename page_order() to buddy_order()

2020-10-16T18:11:19+00:00

The current page_order() can only be called on pages in the buddy
allocator.  For compound pages, you have to use compound_order().  This is
confusing and led to a bug, so rename page_order() to buddy_order().

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Link: https://lkml.kernel.org/r/20201001152259.14932-2-willy@infradead.org
Signed-off-by: Linus Torvalds

mm/readahead: pass a file_ra_state into force_page_cache_ra

2020-10-16T18:11:16+00:00

The file_ra_state being passed into page_cache_sync_readahead() was being
ignored in favour of using the one embedded in the struct file.  The only
caller for which this makes a difference is the fsverity code if the file
has been marked as POSIX_FADV_RANDOM, but it's confusing and worth fixing.

Signed-off-by: David Howells 
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Eric Biggers 
Link: https://lkml.kernel.org/r/20200903140844.14194-10-willy@infradead.org
Signed-off-by: Linus Torvalds

mm/filemap: fold ra_submit into do_sync_mmap_readahead

2020-10-16T18:11:16+00:00

Fold ra_submit() into its last remaining user and pass the
readahead_control struct to both do_page_cache_ra() and
page_cache_sync_ra().

Signed-off-by: David Howells 
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Eric Biggers 
Link: https://lkml.kernel.org/r/20200903140844.14194-9-willy@infradead.org
Signed-off-by: Linus Torvalds

mm/readahead: pass readahead_control to force_page_cache_ra

2020-10-16T18:11:16+00:00

Reimplement force_page_cache_readahead() as a wrapper around
force_page_cache_ra().  Pass the existing readahead_control from
page_cache_sync_readahead().

Signed-off-by: David Howells 
Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Cc: Eric Biggers 
Link: https://lkml.kernel.org/r/20200903140844.14194-7-willy@infradead.org
Signed-off-by: Linus Torvalds