Make swsusp use memory bitmaps to store its internal information during the
resume phase of the suspend-resume cycle.
If the pfns of saveable pages are saved during the suspend phase instead of
the kernel virtual addresses of these pages, we can use them during the resume
phase directly to set the corresponding bits in a memory bitmap. Then, this
bitmap is used to mark the page frames corresponding to the pages that were
saveable before the suspend (aka "unsafe" page frames).
Next, we allocate as many page frames as needed to store the entire suspend
image and make sure that there will be some extra free "safe" page frames for
the list of PBEs constructed later. Subsequently, the image is loaded and, if
possible, the data loaded from it are written into their "original" page
frames (ie. the ones they had occupied before the suspend).
The image data that cannot be written into their "original" page frames are
loaded into "safe" page frames and their "original" kernel virtual addresses,
as well as the addresses of the "safe" pages containing their copies, are
stored in a list of PBEs. Finally, the list of PBEs is used to copy the
remaining image data into their "original" page frames (this is done
atomically, by the architecture-dependent parts of swsusp).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce the memory bitmap data structure and make swsusp use in the suspend
phase.
The current swsusp's internal data structure is not very efficient from the
memory usage point of view, so it seems reasonable to replace it with a data
structure that will require less memory, such as a pair of bitmaps.
The idea is to use bitmaps that may be allocated as sets of individual pages,
so that we can avoid making allocations of order greater than 0. For this
reason the memory bitmap structure consists of several linked lists of objects
that contain pointers to memory pages with the actual bitmap data. Still, for
a typical system all of these lists fit in a single page, so it's reasonable
to introduce an additional mechanism allowing us to allocate all of them
efficiently without sacrificing the generality of the design. This is done
with the help of the chain_allocator structure and associated functions.
We need to use two memory bitmaps during the suspend phase of the
suspend-resume cycle. One of them is necessary for marking the saveable
pages, and the second is used to mark the pages in which to store the copies
of them (aka image pages).
First, the bitmaps are created and we allocate as many image pages as needed
(the corresponding bits in the second bitmap are set as soon as the pages are
allocated). Second, the bits corresponding to the saveable pages are set in
the first bitmap and the saveable pages are copied to the image pages.
Finally, the first bitmap is used to save the kernel virtual addresses of the
saveable pages and the second one is used to save the contents of the image
pages.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The name of the pagedir_nosave variable does not make sense any more, so it
seems reasonable to change it to something more meaningful.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add comments describing struct snapshot_handle and its members, change the
confusing name of its member 'page' to 'cur'.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement async reads for swsusp resuming.
Crufty old PIII testbox:
15.7 MB/s -> 20.3 MB/s
Sony Vaio:
14.6 MB/s -> 33.3 MB/s
I didn't implement the post-resume bio_set_pages_dirty(). I don't really
understand why resume needs to run set_page_dirty() against these pages.
It might be a worry that this code modifies PG_Uptodate, PG_Error and
PG_Locked against the image pages. Can this possibly affect the resumed-into
kernel? Hopefully not, if we're atomically restoring its mem_map?
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Jens Axboe <axboe@suse.de>
Cc: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This reverts commits
3e3318dee0 [PATCH] swsusp: x86_64 mark special saveable/unsaveable pages
b6370d96e0 [PATCH] swsusp: i386 mark special saveable/unsaveable pages
ce4ab0012b [PATCH] swsusp: add architecture special saveable pages support
because not only do they apparently cause page faults on x86, the
infrastructure doesn't compile on powerpc.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make swsusp allocate only as much memory as needed to store the image data
and metadata during resume.
Without this patch swsusp additionally allocates many page frames that will
conflict with the "original" locations of the image data and are considered
as "unsafe", treating them as "eaten" pages (ie. allocated but unusable).
The patch makes swsusp allocate as many pages as it'll need to store the
data read from the image in one shot, creating a list of allocated "safe"
pages, and use the observation that all pages allocated by it are marked
with the PG_nosave and PG_nosave_free flags set. Namely, when it's about
to load an image page, swsusp can check whether the page frame
corresponding to the "original" location of this page has been allocated
(ie. if the page frame has the PG_nosave and PG_nosave_free flags set) and
if so, it can load the page directly into this page frame. Otherwise it
uses an allocated "safe" page from the list to store the data that will be
copied to their "original" location later on.
This allows us to save many page copyings and page allocations during
resume and in the future it may allow us to load images greater than 50% of
the normal zone.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: "Pavel Machek" <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1. Add architecture specific pages save/restore support. Next two patches
will use this to save/restore 'ACPI NVS' pages.
2. Allow reserved pages 'nosave'. This could avoid save/restore BIOS
reserved pages.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Nigel Cunningham <nigel@suspend2.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add the SNAPSHOT_S2RAM ioctl to the snapshot device.
This ioctl allows a userland application to make the system (previously frozen
with the SNAPSHOT_FREE ioctl) enter the S3 state without freezing processes
and disabling nonboot CPUs for the second time.
This will allow us to implement the suspend-to-disk-and-RAM (STDR)
functionality in the userland suspend tools.
Signed-off-by: Luca Tettamanti <kronos.it@gmail.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch introduces a user space interface for swsusp.
The interface is based on a special character device, called the snapshot
device, that allows user space processes to perform suspend and resume-related
operations with the help of some ioctls and the read()/write() functions.
Additionally it allows these processes to allocate free swap pages from a
selected swap partition, called the resume partition, so that they know which
sectors of the resume partition are available to them.
The interface uses the same low-level system memory snapshot-handling
functions that are used by the built-it swap-writing/reading code of swsusp.
The interface documentation is included in the patch.
The patch assumes that the major and minor numbers of the snapshot device will
be 10 (ie. misc device) and 231, the registration of which has already been
requested.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move externs from C source files to header files.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move the swap-writing/reading code of swsusp to a separate file.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce the low level interface that can be used for handling the
snapshot of the system memory by the in-kernel swap-writing/reading code of
swsusp and the userland interface code (to be introduced shortly).
Also change the way in which swsusp records the allocated swap pages and,
consequently, simplifies the in-kernel swap-writing/reading code (this is
necessary for the userland interface too). To this end, it introduces two
helper functions in mm/swapfile.c, so that the swsusp code does not refer
directly to the swap internals.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix compilation problem in PM headers.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Prevent the kernel from setting the log level to 10 unconditionally during
suspend/resume which was needed in the past for debugging, but generally is
undesirable.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make swsusp use bytes as the image size units, which is needed for future
compatibility.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This makes the swsusp_info structure become the header of the image in the
literal sense (ie. it is saved to the swap and read before any other image
data with the help of the swsusp's swap map structure, so generally it is
treated in the same way as the rest of the image).
The main thing it does is to make swsusp_header contain the offset of the swap
map used to track the image data pages rather than the offset of swsusp_info.
Simultaneously, swsusp_info becomes the first image page written to the swap.
The other changes are generally consequences of the above with a few
exceptions (there's some consolidation in the image reading part as a few
functions turn into trivial wrappers around something else).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make the suspend image size limit tunable via /sys/power/image_size.
It is necessary for systems on which there is a limited amount of swap
available for suspend. It can also be useful for optimizing performance of
swsusp on systems with 1 GB of RAM or more.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Limit the size of the suspend image to approx. 500 MB, which should
improve the overall performance of swsusp on systems with more than 1 GB of
RAM.
It introduces the constant IMAGE_SIZE that can be set to the preferred size
of the image (in MB) and modifies the memory-shrinking part of swsusp to
take this constant into account (500 is the default value of IMAGE_SIZE).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
These two prototypes are already present in sched.h, remove duplicate
version.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch makes swsusp free only as much memory as needed to complete the
suspend and not as much as possible. In the most of cases this should speed
up the suspend and make the system much more responsive after resume,
especially if a GUI (eg. X Windows) is used.
If needed, the old behavior (ie to free as much memory as possible during
suspend) can be restored by unsetting FAST_FREE in power.h
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch introduces the swap map structure that can be used by swsusp for
keeping tracks of data pages written to the swap. The structure itself is
described in a comment within the patch.
The overall idea is to reduce the amount of metadata written to the swap and
to write and read the image pages sequentially, in a file-alike way. This
makes the swap-handling part of swsusp fairly independent of its
snapshot-handling part and will hopefully allow us to completely separate
these two parts in the future.
This patch is needed to remove the suspend image size limit imposed by the
limited size of the swsusp_info structure, which is essential for x86-64
systems with more than 512 MB of RAM.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch makes only the functions in swsusp.c call functions in snapshot.c
and not both ways. It also moves the check for available swap out of
swsusp_suspend() which is necessary for separating the swap-handling functions
in swsusp from the core code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch simplifies the relocation of the page backup list (aka pagedir)
during resume.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The changes made by this patch are necessary for the pagedir relocation
simplification in the next patch. Additionally, these changes allow us to
drop check_pagedir() and make get_safe_page() be a one-line wrapper around
alloc_image_page() (get_safe_page() goes to snapshot.c, because
alloc_image_page() is static and it does not make sense to export it).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch makes swsusp use the PG_nosave and PG_nosave_free flags to
mark pages that should be freed in case of an error during resume.
This allows us to simplify the code and to use swsusp_free() in all of the
swsusp's resume error paths, which makes them actually work.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch moves the functionality of swsusp related to creating and
handling the snapshot of memory to a separate file, snapshot.c
This should enable us to untangle the code in the future and eventually to
implement some parts of swsusp.c in the user space.
The patch does not change the code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following patch makes swsusp avoid problems during resume if there are
too many pages to save on suspend. It adds a constant that allows us to
verify if we are going to save too many pages and implements the check
(this is done as early as we can tell that the check will trigger, which is
in swsusp_alloc()).
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Rafael J. Wysocki