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4034247a0d
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 <neilb@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Chao Yu <chao@kernel.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| auth_gss | ||
| xprtrdma | ||
| addr.c | ||
| auth_null.c | ||
| auth_unix.c | ||
| auth.c | ||
| backchannel_rqst.c | ||
| cache.c | ||
| clnt.c | ||
| debugfs.c | ||
| fail.h | ||
| Kconfig | ||
| Makefile | ||
| netns.h | ||
| rpc_pipe.c | ||
| rpcb_clnt.c | ||
| sched.c | ||
| socklib.c | ||
| socklib.h | ||
| stats.c | ||
| sunrpc_syms.c | ||
| sunrpc.h | ||
| svc_xprt.c | ||
| svc.c | ||
| svcauth_unix.c | ||
| svcauth.c | ||
| svcsock.c | ||
| sysctl.c | ||
| sysfs.c | ||
| sysfs.h | ||
| timer.c | ||
| xdr.c | ||
| xprt.c | ||
| xprtmultipath.c | ||
| xprtsock.c | ||