linux/include
Matthew Wilcox (Oracle) 57417cebc9 XArray: add xa_get_order
Patch series "Fix read-only THP for non-tmpfs filesystems".

As described more verbosely in the [3/3] changelog, we can inadvertently
put an order-0 page in the page cache which occupies 512 consecutive
entries.  Users are running into this if they enable the
READ_ONLY_THP_FOR_FS config option; see
https://bugzilla.kernel.org/show_bug.cgi?id=206569 and Qian Cai has also
reported it here:
https://lore.kernel.org/lkml/20200616013309.GB815@lca.pw/

This is a rather intrusive way of fixing the problem, but has the
advantage that I've actually been testing it with the THP patches, which
means that it sees far more use than it does upstream -- indeed, Song has
been entirely unable to reproduce it.  It also has the advantage that it
removes a few patches from my gargantuan backlog of THP patches.

This patch (of 3):

This function returns the order of the entry at the index.  We need this
because there isn't space in the shadow entry to encode its order.

[akpm@linux-foundation.org: export xa_get_order to modules]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Qian Cai <cai@lca.pw>
Cc: Song Liu <songliubraving@fb.com>
Link: https://lkml.kernel.org/r/20200903183029.14930-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20200903183029.14930-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-16 11:11:15 -07:00
..
acpi ACPI updates for 5.10-rc1 2020-10-14 11:42:04 -07:00
asm-generic dma-mapping updates for 5.10 2020-10-15 14:43:29 -07:00
clocksource
crypto X.509: Fix modular build of public_key_sm2 2020-10-08 16:39:14 +11:00
drm sound updates for 5.10 2020-10-15 11:07:44 -07:00
dt-bindings sound updates for 5.10 2020-10-15 11:07:44 -07:00
keys
kunit KUnit: KASAN Integration 2020-10-13 18:38:32 -07:00
kvm
linux XArray: add xa_get_order 2020-10-16 11:11:15 -07:00
math-emu
media Linux 5.9-rc7 2020-10-04 12:19:12 +02:00
memory
misc
net Merge branch 'work.csum_and_copy' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-10-12 16:24:13 -07:00
pcmcia
ras
rdma
scsi SCSI misc on 20201013 2020-10-14 15:15:35 -07:00
soc USB/PHY/Thunderbolt driver patches for 5.10-rc1 2020-10-15 09:51:18 -07:00
sound ASoC: Updates for v5.10 2020-10-12 16:08:57 +02:00
target
trace sound updates for 5.10 2020-10-15 11:07:44 -07:00
uapi \n 2020-10-15 14:56:15 -07:00
vdso
video
xen arm/arm64: xen: Fix to convert percpu address to gfn correctly 2020-10-07 07:08:43 +02:00