Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapped files

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To: <a.p.zijlstra@...>
Cc: <miklos@...>, <salikhmetov@...>, <linux-mm@...>, <jakob@...>, <linux-kernel@...>, <valdis.kletnieks@...>, <riel@...>, <ksm@...>, <staubach@...>, <jesper.juhl@...>, <torvalds@...>, <akpm@...>, <protasnb@...>, <r.e.wolff@...>, <hidave.darkstar@...>, <hch@...>
Date: Friday, January 18, 2008 - 7:36 am

> Possibly, I didn't see a quick way to break that iteration.

Maybe i_mmap_lock isn't needed at all, since msync holds mmap_sem,
which protects the prio tree as well, no?


Yes :)

There could also be nasty performance corner cases, like having a huge
file mapped thousands of times, and having only a couple of pages
dirtied between MS_ASYNC invocations.  Then most of that page table
walking would be just unnecessary overhead.

There's something to be said for walking only the dirty pages, and
doing page_mkclean on them, even if in some cases that would be
slower.

But I have a strong feeling of deja vu, and last time it ended with
Andrew not liking the whole thing...

Miklos
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Messages in current thread:
[PATCH -v6 0/2] Fixing the issue with memory-mapped file times, Anton Salikhmetov, (Thu Jan 17, 6:31 pm)
Re: [PATCH -v6 0/2] Fixing the issue with memory-mapped file..., Anton Salikhmetov, (Fri Jan 18, 3:48 pm)
Re: [PATCH -v6 0/2] Fixing the issue with memory-mapped file..., Anton Salikhmetov, (Fri Jan 18, 6:31 am)
[PATCH -v6 2/2] Updating ctime and mtime for memory-mapped f..., Anton Salikhmetov, (Thu Jan 17, 6:31 pm)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Miklos Szeredi, (Fri Jan 18, 7:36 am)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Mon Jan 21, 10:36 am)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Fri Jan 18, 3:58 pm)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Fri Jan 18, 5:03 pm)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Fri Jan 18, 6:04 pm)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Fri Jan 18, 6:35 pm)
Re: [PATCH -v6 2/2] Updating ctime and mtime for memory-mapp..., Anton Salikhmetov, (Fri Jan 18, 6:39 am)
[PATCH -v6 1/2] Massive code cleanup of sys_msync(), Anton Salikhmetov, (Thu Jan 17, 6:31 pm)
Re: [PATCH -v6 1/2] Massive code cleanup of sys_msync(), Miklos Szeredi, (Fri Jan 18, 5:33 am)
Re: [PATCH -v6 1/2] Massive code cleanup of sys_msync(), Anton Salikhmetov, (Fri Jan 18, 6:30 am)