<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/git/stable/linux.git/fs/xfs/kmem.c, branch master</title>
<subtitle>Linux kernel stable tree</subtitle>
<id>https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/atom?h=master</id>
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<updated>2024-02-13T12:37:34+00:00</updated>
<entry>
<title>xfs: convert kmem_alloc() to kmalloc()</title>
<updated>2024-02-13T12:37:34+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2024-01-15T22:59:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f078d4ea827607867d42fb3b2ef907caf86ce49d'/>
<id>urn:sha1:f078d4ea827607867d42fb3b2ef907caf86ce49d</id>
<content type='text'>
kmem_alloc() is just a thin wrapper around kmalloc() these days.
Convert everything to use kmalloc() so we can get rid of the
wrapper.

Note: the transaction region allocation in xlog_add_to_transaction()
can be a high order allocation. Converting it to use
kmalloc(__GFP_NOFAIL) results in warnings in the page allocation
code being triggered because the mm subsystem does not want us to
use __GFP_NOFAIL with high order allocations like we've been doing
with the kmem_alloc() wrapper for a couple of decades. Hence this
specific case gets converted to xlog_kvmalloc() rather than
kmalloc() to avoid this issue.

Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: "Darrick J. Wong" &lt;djwong@kernel.org&gt;
Signed-off-by: Chandan Babu R &lt;chandanbabu@kernel.org&gt;
</content>
</entry>
<entry>
<title>mm: introduce memalloc_retry_wait()</title>
<updated>2022-01-15T14:30:29+00:00</updated>
<author>
<name>NeilBrown</name>
<email>neilb@suse.de</email>
</author>
<published>2022-01-14T22:07:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4034247a0d6ab281ba3293798ce67af494d86129'/>
<id>urn:sha1:4034247a0d6ab281ba3293798ce67af494d86129</id>
<content type='text'>
Various places in the kernel - largely in filesystems - respond to a
memory allocation failure by looping around and re-trying.  Some of
these cannot conveniently use __GFP_NOFAIL, for reasons such as:

 - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on
 - a need to check for the process being signalled between failures
 - the possibility that other recovery actions could be performed
 - the allocation is quite deep in support code, and passing down an
   extra flag to say if __GFP_NOFAIL is wanted would be clumsy.

Many of these currently use congestion_wait() which (in almost all
cases) simply waits the given timeout - congestion isn't tracked for
most devices.

It isn't clear what the best delay is for loops, but it is clear that
the various filesystems shouldn't be responsible for choosing a timeout.

This patch introduces memalloc_retry_wait() with takes on that
responsibility.  Code that wants to retry a memory allocation can call
this function passing the GFP flags that were used.  It will wait
however is appropriate.

For now, it only considers __GFP_NORETRY and whatever
gfpflags_allow_blocking() tests.  If blocking is allowed without
__GFP_NORETRY, then alloc_page either made some reclaim progress, or
waited for a while, before failing.  So there is no need for much
further waiting.  memalloc_retry_wait() will wait until the current
jiffie ends.  If this condition is not met, then alloc_page() won't have
waited much if at all.  In that case memalloc_retry_wait() waits about
200ms.  This is the delay that most current loops uses.

linux/sched/mm.h needs to be included in some files now,
but linux/backing-dev.h does not.

Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name
Signed-off-by: NeilBrown &lt;neilb@suse.de&gt;
Cc: Dave Chinner &lt;david@fromorbit.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
Cc: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
Cc: Chao Yu &lt;chao@kernel.org&gt;
Cc: Darrick J. Wong &lt;djwong@kernel.org&gt;
Cc: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>xfs: replace kmem_alloc_large() with kvmalloc()</title>
<updated>2021-08-09T22:57:43+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2021-08-09T17:10:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d634525db63e9e946c3229fb93c8d9b763afbaf3'/>
<id>urn:sha1:d634525db63e9e946c3229fb93c8d9b763afbaf3</id>
<content type='text'>
There is no reason for this wrapper existing anymore. All the places
that use KM_NOFS allocation are within transaction contexts and
hence covered by memalloc_nofs_save/restore contexts. Hence we don't
need any special handling of vmalloc for large IOs anymore and
so special casing this code isn't necessary.

Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Signed-off-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
</content>
</entry>
<entry>
<title>xfs: remove kmem_alloc_io()</title>
<updated>2021-08-09T22:57:43+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2021-08-09T17:10:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=98fe2c3cef21b784e2efd1d9d891430d95b4f073'/>
<id>urn:sha1:98fe2c3cef21b784e2efd1d9d891430d95b4f073</id>
<content type='text'>
Since commit 59bb47985c1d ("mm, sl[aou]b: guarantee natural alignment
for kmalloc(power-of-two)"), the core slab code now guarantees slab
alignment in all situations sufficient for IO purposes (i.e. minimum
of 512 byte alignment of &gt;= 512 byte sized heap allocations) we no
longer need the workaround in the XFS code to provide this
guarantee.

Replace the use of kmem_alloc_io() with kmem_alloc() or
kmem_alloc_large() appropriately, and remove the kmem_alloc_io()
interface altogether.

Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
Signed-off-by: Darrick J. Wong &lt;djwong@kernel.org&gt;
</content>
</entry>
<entry>
<title>xfs: remove kmem_realloc()</title>
<updated>2020-09-07T01:05:51+00:00</updated>
<author>
<name>Carlos Maiolino</name>
<email>cmaiolino@redhat.com</email>
</author>
<published>2020-08-26T21:05:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=771915c4f68889b8c41092a928c604c9cd279927'/>
<id>urn:sha1:771915c4f68889b8c41092a928c604c9cd279927</id>
<content type='text'>
Remove kmem_realloc() function and convert its users to use MM API
directly (krealloc())

Signed-off-by: Carlos Maiolino &lt;cmaiolino@redhat.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
</content>
</entry>
<entry>
<title>xfs: remove xfs_zone_{alloc,zalloc} helpers</title>
<updated>2020-07-29T03:24:14+00:00</updated>
<author>
<name>Carlos Maiolino</name>
<email>cmaiolino@redhat.com</email>
</author>
<published>2020-07-22T16:23:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=bae633a4a283afc8ceff5672c1f4f096d0558d70'/>
<id>urn:sha1:bae633a4a283afc8ceff5672c1f4f096d0558d70</id>
<content type='text'>
All their users have been converted to use MM API directly, no need to
keep them around anymore.

Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Carlos Maiolino &lt;cmaiolino@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
</content>
</entry>
<entry>
<title>mm: remove the pgprot argument to __vmalloc</title>
<updated>2020-06-02T17:59:11+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2020-06-02T04:51:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=88dca4ca5a93d2c09e5bbc6a62fbfc3af83c4fca'/>
<id>urn:sha1:88dca4ca5a93d2c09e5bbc6a62fbfc3af83c4fca</id>
<content type='text'>
The pgprot argument to __vmalloc is always PAGE_KERNEL now, so remove it.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Reviewed-by: Michael Kelley &lt;mikelley@microsoft.com&gt; [hyperv]
Acked-by: Gao Xiang &lt;xiang@kernel.org&gt; [erofs]
Acked-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Cc: Christian Borntraeger &lt;borntraeger@de.ibm.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@c-s.fr&gt;
Cc: Daniel Vetter &lt;daniel.vetter@ffwll.ch&gt;
Cc: David Airlie &lt;airlied@linux.ie&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: Haiyang Zhang &lt;haiyangz@microsoft.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: "K. Y. Srinivasan" &lt;kys@microsoft.com&gt;
Cc: Laura Abbott &lt;labbott@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Nitin Gupta &lt;ngupta@vflare.org&gt;
Cc: Robin Murphy &lt;robin.murphy@arm.com&gt;
Cc: Sakari Ailus &lt;sakari.ailus@linux.intel.com&gt;
Cc: Stephen Hemminger &lt;sthemmin@microsoft.com&gt;
Cc: Sumit Semwal &lt;sumit.semwal@linaro.org&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Catalin Marinas &lt;catalin.marinas@arm.com&gt;
Cc: Heiko Carstens &lt;heiko.carstens@de.ibm.com&gt;
Cc: Paul Mackerras &lt;paulus@ozlabs.org&gt;
Cc: Vasily Gorbik &lt;gor@linux.ibm.com&gt;
Cc: Will Deacon &lt;will@kernel.org&gt;
Link: http://lkml.kernel.org/r/20200414131348.444715-22-hch@lst.de
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
</entry>
<entry>
<title>xfs: Correct comment tyops -&gt; typos</title>
<updated>2019-11-10T18:21:57+00:00</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2019-11-07T21:24:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cf085a1b5d221448c0c7425f3b9b9a9e2134e53e'/>
<id>urn:sha1:cf085a1b5d221448c0c7425f3b9b9a9e2134e53e</id>
<content type='text'>
Just fix the typos checkpatch notices...

Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Reviewed-by: Bill O'Donnell &lt;billodo@redhat.com&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
</content>
</entry>
<entry>
<title>xfs: add kmem_alloc_io()</title>
<updated>2019-08-27T00:43:15+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2019-08-26T19:08:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f8f9ee479439c1be9e33c4404912a2a112c46200'/>
<id>urn:sha1:f8f9ee479439c1be9e33c4404912a2a112c46200</id>
<content type='text'>
Memory we use to submit for IO needs strict alignment to the
underlying driver contraints. Worst case, this is 512 bytes. Given
that all allocations for IO are always a power of 2 multiple of 512
bytes, the kernel heap provides natural alignment for objects of
these sizes and that suffices.

Until, of course, memory debugging of some kind is turned on (e.g.
red zones, poisoning, KASAN) and then the alignment of the heap
objects is thrown out the window. Then we get weird IO errors and
data corruption problems because drivers don't validate alignment
and do the wrong thing when passed unaligned memory buffers in bios.

TO fix this, introduce kmem_alloc_io(), which will guaranteeat least
512 byte alignment of buffers for IO, even if memory debugging
options are turned on. It is assumed that the minimum allocation
size will be 512 bytes, and that sizes will be power of 2 mulitples
of 512 bytes.

Use this everywhere we allocate buffers for IO.

This no longer fails with log recovery errors when KASAN is enabled
due to the brd driver not handling unaligned memory buffers:

# mkfs.xfs -f /dev/ram0 ; mount /dev/ram0 /mnt/test

Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
</content>
</entry>
<entry>
<title>xfs: add kmem allocation trace points</title>
<updated>2019-08-27T00:43:14+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>dchinner@redhat.com</email>
</author>
<published>2019-08-26T19:08:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.rulkc.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=0ad95687c3adb91e762d0f6ea50a6b1137300e19'/>
<id>urn:sha1:0ad95687c3adb91e762d0f6ea50a6b1137300e19</id>
<content type='text'>
When trying to correlate XFS kernel allocations to memory reclaim
behaviour, it is useful to know what allocations XFS is actually
attempting. This information is not directly available from
tracepoints in the generic memory allocation and reclaim
tracepoints, so these new trace points provide a high level
indication of what the XFS memory demand actually is.

There is no per-filesystem context in this code, so we just trace
the type of allocation, the size and the allocation constraints.
The kmem code also doesn't include much of the common XFS headers,
so there are a few definitions that need to be added to the trace
headers and a couple of types that need to be made common to avoid
needing to include the whole world in the kmem code.

Signed-off-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Reviewed-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
Signed-off-by: Darrick J. Wong &lt;darrick.wong@oracle.com&gt;
</content>
</entry>
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