All existing callers guarantee that the page does not have a
pre-existing dequeue pending. Thus, if the page is dequeued before
pqbatch_submit() acquires the page queue lock, we do not need to do
anything since vm_page_dequeue_complete() takes care of clearing all
page queue state flags for us.
With this change, vm_page_pqbatch_submit() has the nice property that it
does not directly modify any fields in the page structure.
Reviewed by: alc, kib
Tested by: pho (part of a larger change)
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21372
It will become useful for the page daemon to be able to directly create
a batch queue entry for a page, and without modifying the page
structure. Rename vm_pqbatch_submit_page() to vm_page_pqbatch_submit()
to keep the namespace consistent. No functional change intended.
Reviewed by: alc, kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21369
- Add a vm_pagequeue_remove() function to physically remove a page
from its queue and update the queue length.
- Remove vm_page_pagequeue_lockptr() and let vm_page_pagequeue()
return NULL for dequeued pages.
- Avoid unnecessarily reloading the queue index if vm_page_dequeue()
loses a race with a concurrent queue operation.
- Correct an always-true assertion: vm_page_dequeue() may be called
from the page allocator with the page unlocked. The assertion
m->order == VM_NFREEORDER simply tests whether the page has been
removed from the vm_phys free lists; instead, check whether the
page belongs to an object.
Reviewed by: kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21341
It is useful for testing purposes to be able to drain UMA caches, so
do not limit the sysctl to DIAGNOSTIC kernels.
MFC after: 1 week
Sponsored by: Netflix
As of r332974 the page daemon does not requeue pages during a scan
of the active queue, so there is not much value in doing so here
either.
Reviewed by: alc, dougm, kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21343
VM_OBJECT_DROP/VM_OBJECT_PICKUP to handle functions that are called with
uncertain lock state.
Reviewed by: kib, markj
Tested by: pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21310
NUMA domain that the pages describe. Patch original from gallatin.
Reviewed by: kib
Tested by: pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21252
Require the vnode to be locked for the VOP_UNSET_TEXT() call. This
will be used by the following bug fix for a tmpfs issue.
Tested by: sbruno, pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
NUMA aware boot time memory allocator that will be used to allocate early
domain correct structures. Code partially submitted by gallatin.
Reviewed by: gallatin, kib
Tested by: pho
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21251
In addition to pagedaemon initiating OOM, also do it from the
vm_fault() internals. Namely, if the thread waits for a free page to
satisfy page fault some preconfigured amount of time, trigger OOM.
These triggers are rate-limited, due to a usual case of several
threads of the same multi-threaded process to enter fault handler
simultaneously. The faults from pagedaemon threads participate in the
calculation of OOM rate, but are not under the limit.
Reviewed by: markj (previous version)
Tested by: pho
Discussed with: alc
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D13671
doing so adds more flexibility with less redundant code.
Reviewed by: jhb, markj, kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21250
expression howmany(BBSIZE, PAGE_SIZE), where BBSIZE is the size of the
boot block area. That can be less than 2 if PAGE_SIZE is big.
swapon(8) has an option to trim (delete) all the blocks of a device at
startup. However, if the first of those blocks is a bsd label, then
trimming those blocks is destructive. Change swapon to leave the
first BBSIZE bytes untrimmed.
Update manual pages to reflect changes in how swapon and how it may be
used, espeically in association with savecore.
Reviewed by: alc
Approved by: markj (mentor)
MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D21191
During early stages of kern_exec(), including strings copyout,
p_textvp for init is NULL. This prevented stack grow from working for
init execution.
Without stack gap enabled, initial stack segment size is enough for
strings passed by kernel to init. With the gap enabled, the used
address might fall out of the initial segment, which kills init.
Exclude initproc from the check for contexts which should not cause
stack grow in the target map.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
- UMA_XDOMAIN enables an additional per-cpu bucket for freed memory that
was freed on a different domain from where it was allocated. This is
only used for UMA_ZONE_NUMA (first-touch) zones.
- UMA_FIRSTTOUCH sets the default UMA policy to be first-touch for all
zones. This tries to maintain locality for kernel memory.
Reviewed by: gallatin, alc, kib
Tested by: pho, gallatin
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20929
Both of these functions atomically unwire a page, optionally attempt
to free the page, and enqueue or requeue the page. Add functions
vm_page_release() and vm_page_release_locked() to perform the same task.
The latter must be called with the page's object lock held.
As a side effect of this refactoring, the buffer cache will no longer
attempt to free mapped pages when completing direct I/O. This is
consistent with the handling of pages by sendfile(SF_NOCACHE).
Reviewed by: alc, kib
MFC after: 2 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20986
counter, and the final freeing of freed swap blocks, outside the
region where an object lock is held. Correct some style(9) and
spelling errors. Change a panic() to a KASSERT(). Change a boolean_t
to a bool.
Suggested by: alc
Reviewed by: alc
Approved by: kib, markj (mentors)
Differential Revision: https://reviews.freebsd.org/D21093
I would like to use the name vm_page_release() for a different purpose,
and vm_page_{import,release}() are local to vm_page.c.
Reviewed by: kib
MFC after: 1 week
entry, combining code currently in vm_map_unwire and
vm_map_wire_locked into a single function, called by each of them for
entries in transition.
Discussed with: kib, markj
Reviewed by: alc
Approved by: kib, markj (mentors, implicit)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D20833
The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics. The remaining essential
differences are that holds are not counted as a reference with respect
to LRU, and holds have an implicit free-on-last unhold semantic whereas
vm_page_unwire() callers must explicitly determine whether to free the
page once the last reference to the page is released.
This change removes the KPIs which directly manipulate hold_count.
Functions such as vm_fault_quick_hold_pages() now return wired pages
instead. Since r328977 the overhead of maintaining LRU for wired pages
is lower, and in many cases vm_fault_quick_hold_pages() callers would
swap holds for wirings on the returned pages anyway, so with this change
we remove a number of page lock acquisitions.
No functional change is intended. __FreeBSD_version is bumped.
Reviewed by: alc, kib
Discussed with: jeff
Discussed with: jhb, np (cxgbe)
Tested by: pho (previous version)
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D19247
Pages with PG_PCPU_CACHE set cannot have been allocated from a
reservation, so as an optimization, skip the call to
vm_reserv_free_page() in this case. Otherwise, the access of
the corresponding reservation structure often results in a cache
miss.
Reviewed by: alc, kib
Discussed with: jeff
MFC after: 2 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20859
Some workloads benefit from having a per-CPU cache for
VM_FREEPOOL_DIRECT pages.
Reviewed by: dougm, kib
Discussed with: alc, jeff
MFC after: 2 weeks
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20858
comment. Rewrite that comment to improve its clarity.
Reported by: cem
Reviewed by: alc, cem
Approved by: kib, markj (mentors, implicit)
Differential Revision: https://reviews.freebsd.org/D20871
after the one where the possible block allocation begins, and allocate
a larger number of blocks than the current limit. This does not affect
the limit on minimum allocation size, which still cannot exceed
BLIST_MAX_ALLOC.
Use this change to modify swp_pager_getswapspace and its callers, so
that they can allocate more than BLIST_MAX_ALLOC blocks if they are
available.
Tested by: pho
Approved by: markj (mentor)
Differential Revision: https://reviews.freebsd.org/D20579
swap_pager_swapoff_object and swp_pager_force_pagein so that they can
page in multiple pages at a time to a swap device, rather than doing
one I/O operation for each page.
Tested by: pho
Submitted by: ota_j.email.ne.jp (Yoshihiro Ota)
Reviewed by: alc, markj, kib
Approved by: kib, markj (mentors)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20635
pmap_ts_referenced returns a count, not a boolean, and is supposed to
have int as the return type not boolean_t.
This worked previously because boolean_t is an int typedef.
Discussed with: kib
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
When QUEUE_MACRO_DEBUG_TRASH is configured, removing a queue element
invalidates its queue linkage pointers. vm_pageout_collect_batch()
was relying on these pointers remaining valid after a removal, so
modify it to fetch the next queued page before dequeuing the current
page.
Submitted by: Don Morris <dgmorris@earthlink.net>
Reviewed by: cem, vangyzen
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D20842
Only free pages to the cache when they were allocated from that cache.
This mitigates rapid fragmentation of physical memory seen during
poudriere's dependency calculation phase. In particular, pages
belonging to broken reservations are no longer freed to the per-CPU
cache, so they get a chance to coalesce with freed pages during the
break. Otherwise, the optimized CoW handler may create object
chains in which multiple objects contain pages from the same
reservation, and the order in which we do object termination means
that the reservation is broken before all of those pages are freed,
so some of them end up in the per-CPU cache and thus permanently
fragment physical memory.
The flag may also be useful for eliding calls to vm_reserv_free_page(),
thus avoiding memory accesses for data that is likely not present
in the CPU caches.
Reviewed by: alc
Discussed with: jeff
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D20763
feature bit.
In particular, allocate the bit to opt-out the image from implicit
PROTMAX enablement. Provide procctl(2) verbs to set and query
implicit PROTMAX handling. The knobs mimic the same per-image flag
and per-process controls for ASLR.
Reviewed by: emaste, markj (previous version)
Discussed with: brooks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D20795
Use it to indicate whether the page may be safely freed following
its removal from the object. Also change vm_page_remove() to assume
that the page's object pointer is non-NULL, and have callers perform
this check instead.
This is a step towards an implementation of an atomic reference counter
for each physical page structure.
Reviewed by: alc, dougm, kib
MFC after: 1 week
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D20758
Since the only caller to vm_map_splay is vm_map_lookup_entry, move the
implementation of vm_map_splay into vm_map_lookup_helper, called by
vm_map_lookup_entry.
vm_map_lookup_entry returns the greatest entry less than or equal to a
given address, but in many cases the caller wants the least entry
greater than or equal to the address and uses the next pointer to get
to it. Provide an alternative interface to lookup,
vm_map_lookup_entry_ge, to provide the latter behavior, and let
callers use one or the other rather than having them use the next
pointer after a lookup miss to get what they really want.
In vm_map_growstack, the caller wants an entry that includes a given
address, and either the preceding or next entry depending on the value
of eflags in the first entry. Incorporate that behavior into
vm_map_lookup_helper, the function that implements all of these
lookups.
Eliminate some temporary variables used with vm_map_lookup_entry, but
inessential.
Reviewed by: markj (earlier version)
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D20664
error response after clipping the first map entry in the region to be
reserved. This creates a pair of matching entries that should have
been "simplified" back into one, or never created. This change defers
the clipping of that entry until those two vm_map_protect failure
cases have been ruled out.
Reviewed by: alc
Approved by: markj (mentor)
Differential Revision: https://reviews.freebsd.org/D20711
A new macro PROT_MAX() alters a protection value so it can be OR'd with
a regular protection value to specify the maximum permissions. If
present, these flags specify the maximum permissions.
While these flags are non-portable, they can be used in portable code
with simple ifdefs to expand PROT_MAX() to 0.
This change allows (e.g.) a region that must be writable during run-time
linking or JIT code generation to be made permanently read+execute after
writes are complete. This complements W^X protections allowing more
precise control by the programmer.
This change alters mprotect argument checking and returns an error when
unhandled protection flags are set. This differs from POSIX (in that
POSIX only specifies an error), but is the documented behavior on Linux
and more closely matches historical mmap behavior.
In addition to explicit setting of the maximum permissions, an
experimental sysctl vm.imply_prot_max causes mmap to assume that the
initial permissions requested should be the maximum when the sysctl is
set to 1. PROT_NONE mappings are excluded from this for compatibility
with rtld and other consumers that use such mappings to reserve
address space before mapping contents into part of the reservation. A
final version this is expected to provide per-binary and per-process
opt-in/out options and this sysctl will go away in its current form.
As such it is undocumented.
Reviewed by: emaste, kib (prior version), markj
Additional suggestions from: alc
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D18880
