A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES().

o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return,

A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES().

o With new KPI consumers can request contiguous ranges of pages, and
unlike before, all pages will be kept busied on return, like it was
done before with the 'reqpage' only. Now the reqpage goes away. With
new interface it is easier to implement code protected from race
conditions.

Such arrayed requests for now should be preceeded by a call to
vm_pager_haspage() to make sure that request is possible. This
could be improved later, making vm_pager_haspage() obsolete.

Strenghtening the promises on the business of the array of pages
allows us to remove such hacks as swp_pager_free_nrpage() and
vm_pager_free_nonreq().

o New KPI accepts two integer pointers that may optionally point at
values for read ahead and read behind, that a pager may do, if it
can. These pages are completely owned by pager, and not controlled
by the caller.

This shifts the UFS-specific readahead logic from vm_fault.c, which
should be file system agnostic, into vnode_pager.c. It also removes
one VOP_BMAP() request per hard fault.

Discussed with: kib, alc, jeff, scottl
Sponsored by: Nginx, Inc.
Sponsored by: Netflix

show more ...

Finish merging from head, messed up in previous attempt

Merge from head

Catch up with head, primarily for the 1.14.4.0 firmware.

Merge ^/head r285924 through r286421.

- Make 'struct buf *buf' private to vfs_bio.c. Having a global variable
'buf' is inconvenient and has lead me to some irritating to discover
bugs over the years. It also makes it more challen

- Make 'struct buf *buf' private to vfs_bio.c. Having a global variable
'buf' is inconvenient and has lead me to some irritating to discover
bugs over the years. It also makes it more challenging to refactor
the buf allocation system.
- Move swbuf and declare it as an extern in vfs_bio.c. This is still
not perfect but better than it was before.
- Eliminate the unused ffs function that relied on knowledge of the buf
array.
- Move the shutdown code that iterates over the buf array into vfs_bio.c.

Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division

show more ...

Merge ^/head r285793 through r285923.

Refactor unmapped buffer address handling.
- Use pointer assignment rather than a combination of pointers and
flags to switch buffers between unmapped and mapped. This eliminates
multiple fla

Refactor unmapped buffer address handling.
- Use pointer assignment rather than a combination of pointers and
flags to switch buffers between unmapped and mapped. This eliminates
multiple flags and generally simplifies the logic.
- Eliminate b_saveaddr since it is only used with pager bufs which have
their b_data re-initialized on each allocation.
- Gather up some convenience routines in the buffer cache for
manipulating buf space and buf malloc space.
- Add an inline, buf_mapped(), to standardize checks around unmapped
buffers.

In collaboration with: mlaier
Reviewed by: kib
Tested by: pho (many small revisions ago)
Sponsored by: EMC / Isilon Storage Division

show more ...

Catch up with HEAD (r280229-r284686).

Merge ^/head r284188 through r284643.

Merge from head @274131

o Un-inline vm_pager_get_pages(), vm_pager_get_pages_async().
o Provide an extensive set of assertions for input array of pages.
o Remove now duplicate assertions from different pagers.

Sponsored by

o Un-inline vm_pager_get_pages(), vm_pager_get_pages_async().
o Provide an extensive set of assertions for input array of pages.
o Remove now duplicate assertions from different pagers.

Sponsored by: Nginx, Inc.
Sponsored by: Netflix

show more ...

Merge sync of head

Merge from HEAD

MFH: r278968-r280640

Sponsored by: The FreeBSD Foundation

Merge r278538 through r280226.

o Enhance vm_pager_free_nonreq() function:
- Allow to call the function with vm object lock held.
- Allow to specify reqpage that doesn't match any page in the region,
meaning freeing all pag

o Enhance vm_pager_free_nonreq() function:
- Allow to call the function with vm object lock held.
- Allow to specify reqpage that doesn't match any page in the region,
meaning freeing all pages.
o Utilize the new function in couple more places in vnode pager.

Reviewed by: alc, kib
Sponsored by: Netflix
Sponsored by: Nginx, Inc.

show more ...

Merge from head

Merging ^/head r279596 through r279758.

Merge r278538 through r279716.

- In vnode_pager_generic_getpages() use different free counters for
synchronous and asynchronous requests. The latter can saturate the
I/O and we do not want them to affect regular paging.
- All

- In vnode_pager_generic_getpages() use different free counters for
synchronous and asynchronous requests. The latter can saturate the
I/O and we do not want them to affect regular paging.
- Allocate the pbuf at the very beginning of the function, so that
if we are low on certain kind of pbufs don't even proceed to BMAP,
but sleep.

Reviewed by: kib
Sponsored by: Nginx, Inc.
Sponsored by: Netflix

show more ...

Merge from head@274682

Sync to HEAD@r272516.

IFC @r271694

Avoid an exclusive acquisition of the object lock on the expected execution
path through the NFS clients' getpages functions.

Introduce vm_pager_free_nonreq(). This function can be used to eliminat

Avoid an exclusive acquisition of the object lock on the expected execution
path through the NFS clients' getpages functions.

Introduce vm_pager_free_nonreq(). This function can be used to eliminate
code that is duplicated in many getpages functions. Also, in contrast to
the code that currently appears in those getpages functions,
vm_pager_free_nonreq() avoids acquiring an exclusive object lock in one
case.

Reviewed by: kib
MFC after: 6 weeks
Sponsored by: EMC / Isilon Storage Division

show more ...